Blue · Level IV
General. The lowest of the four rungs — a hazard is possible but at its least severe. Worth noting, rarely a reason to change plans.
When the weather closes the trip
China's weather warning colours: what blue, yellow, orange and red shut down
In short
I keep seeing a coloured weather alert in China — what does it mean?
China uses one national warning-signal ladder: blue, yellow, orange and red stand for Level IV (general), Level III (relatively severe), Level II (severe) and Level I (especially severe). Each hazard sets its colours on its own published numbers — rainstorm on 50 mm in 12, 6 or 3 hours and 100 mm in 3; typhoon on Force 6, 8, 10 and 12 winds; fog on visibility under 500 m, 200 m and 50 m; heat on 35°C, 37°C and 40°C. Orange is where a visitor's day starts closing: classes and business suspend at typhoon orange, and at rainstorm orange for anyone in a danger zone. Three red signals — fog, snowstorm, sandstorm — are the only ones whose defence guides name aircraft, trains or expressways at all.
See all recovery guidesApplies to
Any foreign visitor who sees a colour flashed on a weather app, a station or scenic-area board, or the news while travelling in China — coastal or inland, any season.
Check before you rely on it
Naming a suspension is not making it automatic: fog red and snowstorm red both hedge theirs (适时 / 必要时 — as appropriate, when necessary), and only sandstorm red states it flat. Whether your specific train or flight runs is still the railway's or carrier's call on the day, so check 12306 and your airline. Eight hazards carry their thresholds here; cold wave, lightning, hail, drought, frost and haze were not opened this pass and their numbers are not stated.
Information checked:
A colour on a screen is the one part of a Chinese weather warning a visitor can read without the Chinese text. This guide maps the four colours to what they mean, then gives the published number behind every colour of eight hazards and, next to it, exactly what that hazard’s own defence guide says stops at that rung — hedges included.
The one ladder
Blue, yellow, orange, red — lowest to highest
Four levels, ranked by how severe the hazard is. The same colours mean the same thing whatever the hazard.
Yellow · Level III
Relatively severe. Conditions are stepping up. Check the forecast and the operator of anything outdoor or coastal you have booked.
Orange · Level II
Severe. This is where real closures begin — for a typhoon signal, classes and business (bar special industries) are officially told to suspend from orange upward.
Red · Level I
Especially severe — the top rung. Expect the widest closures and assume outdoor and coastal plans are off. Treat travel that day as disrupted.
Source: China Meteorological Administration (中国气象局) Order No. 16, published on www.cma.gov.cn — 气象灾害预警信号发布与传播管理办法 (Measures for the Issuance and Dissemination of Meteorological Disaster Warning Signals), Articles 2–3 (source dated 2007-06-12 (issued as CMA Order No. 16; effective on issuance); read July 25, 2026)
One scheme, every hazard
The colours cover all of these
High temperature and cold wave are rungs of the same ladder — there is only one colour system to learn.
TyphoonRainstormSnowstormCold waveGaleSandstormHigh temperatureDroughtLightningHailFrostHeavy fogHazeRoad icing
Source: China Meteorological Administration (中国气象局) Order No. 16, published on www.cma.gov.cn — 气象灾害预警信号发布与传播管理办法 (Measures for the Issuance and Dissemination of Meteorological Disaster Warning Signals), Articles 2–3 (source dated 2007-06-12 (issued as CMA Order No. 16; effective on issuance); read July 25, 2026)
Worked example
A typhoon signal, colour by colour
As the wind forecast climbs from Force 6 to Force 12, the colour climbs and the closures widen. This is the CMA typhoon-signal standard.
Typhoon blue
Within 24h, average wind reaching Force 6+, or gusts Force 8+, and likely to persist.
Defence guide: stop open-air group activities and dangerous outdoor work at height. Coastal and water activity is the first thing to go.
Typhoon yellow
Within 24h, wind reaching Force 8+, or gusts Force 10+.
Defence guide: stop large indoor and outdoor gatherings and dangerous outdoor work at height.
Typhoon orange
Within 12h, wind reaching Force 10+, or gusts Force 12+.
Defence guide item 2: stop large indoor and outdoor gatherings, suspend classes, suspend business (except special industries); vessels return to port or take shelter.
Typhoon red
Within 6h, wind reaching Force 12+, or gusts Force 14+.
Defence guide item 2: stop gatherings, suspend classes, suspend business (except special industries); sheltering vessels arrange for crews to stay put or move to safety.
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 台风预警信号 (Typhoon warning signals) — colour standards and defence guides (read July 25, 2026)
Every colour, every number
The threshold behind each colour, and what it closes
Eight hazards, transcribed colour by colour from each signal's own CMA standard and defence guide. Where the guide names no closure at a rung, this table says so rather than filling the gap. Threshold pages read 2026-08-22.
Rainstorm · 暴雨
The colour is set by rainfall in a fixed window, so the ladder climbs by the clock as well as by the millimetre: the same 50 mm moves from blue to orange purely because it is forecast to fall in three hours instead of twelve.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Blue | 50 mm or more of rain within 12 hours, or 50 mm already fallen and rain likely to continue. | No closure named. Schools and kindergartens are told to take appropriate measures to keep pupils safe; drivers are warned about standing water and congestion. |
| Yellow | 50 mm or more within 6 hours, or 50 mm already fallen and rain likely to continue. | No general closure. Traffic authorities are to impose traffic control on heavy-rain stretches and direct traffic where water is standing; open-air work in exposed places is suspended. |
| Orange | 50 mm or more within 3 hours, or 50 mm already fallen and rain likely to continue. | Units in danger zones are to suspend classes and business (处于危险地带的单位应当停课、停业) — a location-scoped suspension, not a citywide one. Outdoor work stops. |
| Red | 100 mm or more within 3 hours, or 100 mm already fallen and rain likely to continue. | Gatherings, classes and business stop, special industries excepted (停止集会、停课、停业（除特殊行业外）). |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 暴雨预警信号 (Rainstorm warning signals) — the four colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
Typhoon · 台风
The rung a coastal city reaches decides whether your day is merely windy or officially shut. Note the lead time shortens as the colour climbs — red is a 6-hour horizon, blue a 24-hour one.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Blue | Tropical cyclone impact possible or already happening within 24 hours, with average wind Force 6+ or gusts Force 8+ on the coast or inland, likely to persist. | Open-air group activities and high-altitude or other dangerous outdoor work stop. Vessels take shelter or reroute. |
| Yellow | Same 24-hour horizon, with average wind Force 8+ or gusts Force 10+, likely to persist. | Large indoor and outdoor gatherings stop, as does dangerous outdoor work. |
| Orange | Impact within 12 hours, with average wind Force 10+ or gusts Force 12+, likely to persist. | Large gatherings, classes and business stop, special industries excepted (停止室内外大型集会、停课、停业（除特殊行业外）). Vessels must return to port. |
| Red | Impact within 6 hours, with average wind Force 12+ or gusts Force 14+, likely to persist. | Gatherings, classes and business stop, special industries excepted. The guide also warns that the wind drops or goes still while the eye passes, then returns suddenly — stay put. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 台风预警信号 (Typhoon warning signals) — colour standards and defence guides (read July 25, 2026)
Dense fog · 大雾
This is the hazard that most often reaches an airport. Fog red is one of only three places in the whole national scheme where the official defence guide names aircraft, expressways and ferries.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Yellow | Visibility below 500 m possible within 12 hours, or fog already down to between 200 m and 500 m and set to persist. | No suspension. Airports, expressways and ferry terminals are told to tighten traffic management; drivers to take care. |
| Orange | Visibility below 200 m possible within 6 hours, or fog already between 50 m and 200 m and set to persist. | No suspension named. Airports, expressways and ferry terminals tighten dispatch; vehicles and vessels must strictly control speed. |
| Red | Visibility below 50 m possible within 2 hours, or already below 50 m and set to persist. | Relevant units take traffic-safety control measures as appropriate under their industry rules — the guide's own examples are aircraft takeoffs and landings suspended, expressways temporarily closed and ferries temporarily halted (适时采取交通安全管制措施，如机场暂停飞机起降，高速公路暂时封闭，轮渡暂时停航等). Read the hedge: the measures are named, but they are the operator's call. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 大雾预警信号 (Dense-fog warning signals) — the three colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
Snowstorm · 暴雪
The winter counterpart of the rainstorm ladder, and the only hazard whose red-level guide names trains as well as planes and expressways.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Blue | 4 mm or more of snow within 12 hours, or already 4 mm and continuing, with possible impact on transport or farming. | No closure named at this level. |
| Yellow | 6 mm or more within 12 hours, or already 6 mm and continuing, with possible impact on transport or farming. | No closure named at this level. |
| Orange | 10 mm or more within 6 hours, or already 10 mm and continuing, with major impact possible or already happening. | No closure named at this level. |
| Red | 15 mm or more within 6 hours, or already 15 mm and continuing, with major impact possible or already happening. | Classes and business stop when necessary, special industries excepted; and when necessary aircraft stop taking off and landing, trains stop running and expressways temporarily close (必要时飞机暂停起降，火车暂停运行，高速公路暂时封闭). Both measures carry 必要时 — when necessary — so neither is automatic at red. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 暴雪预警信号 (Snowstorm warning signals) — the four colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
Sandstorm · 沙尘暴
A northern-China spring hazard graded purely by visibility. Its red level is the one place in the scheme where the transport suspension is stated flat, with no 必要时 or 适时 attached.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Yellow | Sandstorm possible within 12 hours (visibility below 1000 m), or already blowing and likely to persist. | No closure named at this level. |
| Orange | Severe sandstorm possible within 6 hours (visibility below 500 m), or already blowing and likely to persist. | Open-air activity and high-altitude or over-water dangerous outdoor work stop. |
| Red | Extremely severe sandstorm possible within 6 hours (visibility below 50 m), or already blowing and likely to persist. | Aircraft stop taking off and landing, trains stop running, expressways temporarily close (飞机暂停起降，火车暂停运行，高速公路暂时封闭) — stated without a hedge, unlike the fog and snowstorm guides. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 沙尘暴预警信号 (Sandstorm warning signals) — the three colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
High temperature · 高温
Three rungs only, and the trigger is a plain thermometer reading — the easiest signal for a visitor to sanity-check against their own weather app.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Yellow | Daily maximum temperature above 35°C for three days running. | No closure. Outdoor activity to be reduced in the afternoon. |
| Orange | Maximum temperature to rise above 37°C within 24 hours. | No closure. Outdoor activity avoided in the hottest hours; continuous working time shortened for people working in the heat. |
| Red | Maximum temperature to rise above 40°C within 24 hours. | Open-air outdoor work stops, special industries excepted (停止户外露天作业（除特殊行业外）). Nothing else is told to close. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 高温预警信号 (High-temperature warning signals) — the three colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
Gale (non-typhoon wind) · 大风
Inland cities never reach a typhoon signal but do reach this one. Its orange rung is unusually specific about who closes: schools and units whose buildings resist wind poorly.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Blue | Within 24 hours, average wind may reach Force 6+ or gusts Force 7+; or wind is already Force 6–7 average, gusts 7–8, and likely to persist. | No closure named at this level. |
| Yellow | Within 12 hours, average wind may reach Force 8+ or gusts Force 9+; or already Force 8–9 average, gusts 9–10, and likely to persist. | Open-air activity and high-altitude dangerous outdoor work stop. |
| Orange | Within 6 hours, average wind may reach Force 10+ or gusts Force 11+; or already Force 10–11 average, gusts 11–12, and likely to persist. | Primary and secondary schools and units whose buildings resist wind poorly are to suspend classes and business (房屋抗风能力较弱的中小学校和单位应当停课、停业) — again scoped by the building, not the city. |
| Red | Within 6 hours, average wind may reach Force 12+ or gusts Force 13+; or already Force 12+ average, gusts Force 13+, and likely to persist. | People are to stay in a wind-safe place and not go out. The guide names no class or business suspension at this level. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 大风预警信号 (Gale warning signals) — the four colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
Road icing · 道路结冰
The only common signal with no quantity in its standard at all — it is graded by lead time and by how badly traffic is expected to be hit, which is why a red here can look mild on a weather app and still shut a road.
| Colour | Official threshold | What the defence guide stops |
|---|---|---|
| Yellow | Road-surface temperature below 0°C with precipitation, and icing that affects traffic possible within 12 hours. | No closure named at this level. |
| Orange | Road-surface temperature below 0°C with precipitation, and icing with a major effect on traffic possible within 6 hours. | No closure named at this level. |
| Red | Road-surface temperature below 0°C with precipitation, and icing with a very large effect on traffic possible or already present within 2 hours. | Transport and police authorities direct traffic and, when necessary, close the iced road to traffic (必要时关闭结冰道路交通). No class or business suspension is named at any rung of this signal. |
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 道路结冰预警信号 (Road-icing warning signals) — the three colour standards and their defence guides (source dated 2022-04-02 (CMA portal page, sourced to 气象灾害预警信号发布与传播办法); read August 22, 2026)
The published facts
What the official warning-signal rules actually say
Each fact links the official source and the day we read it. Sources read 2026-07-25.
Four colours, one national ladder
China's meteorological warning signals are divided into four levels by how severe, urgent and fast-developing the hazard is — Level IV (general), Level III (relatively severe), Level II (severe) and Level I (especially severe) — shown in order by blue, yellow, orange and red, and marked in both Chinese and English. So blue is the lowest rung and red the highest.
Article 3
Source: China Meteorological Administration (中国气象局) Order No. 16, published on www.cma.gov.cn — 气象灾害预警信号发布与传播管理办法 (Measures for the Issuance and Dissemination of Meteorological Disaster Warning Signals), Articles 2–3 (source dated 2007-06-12 (issued as CMA Order No. 16; effective on issuance); read July 25, 2026)
The same colours cover every hazard
A warning signal is made up of a name, an icon, a standard and a defence guide, and the same colour scheme spans the lot: typhoon, rainstorm, snowstorm, cold wave, gale, sandstorm, high temperature, drought, lightning, hail, frost, heavy fog, haze and road icing. A visitor only has to learn one ladder — high temperature and cold-wave alerts are rungs of it, not a separate system.
Article 2
Source: China Meteorological Administration (中国气象局) Order No. 16, published on www.cma.gov.cn — 气象灾害预警信号发布与传播管理办法 (Measures for the Issuance and Dissemination of Meteorological Disaster Warning Signals), Articles 2–3 (source dated 2007-06-12 (issued as CMA Order No. 16; effective on issuance); read July 25, 2026)
Typhoon orange and red suspend classes and business
On the CMA typhoon-signal standard, the defence guide for both typhoon orange and typhoon red says to stop gatherings, suspend classes and suspend business (except special industries). That is the closure a visitor actually walks into — scenic-area group activity, schools and much day-to-day business stopping — appearing officially from the orange level up.
Typhoon orange & red defence guides
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 台风预警信号 (Typhoon warning signals) — colour standards and defence guides (read July 25, 2026)
Outdoor and coastal activity stops from blue
You do not have to wait for red. Even at typhoon blue — Force 6+ wind within 24 hours — the defence guide is to stop open-air group activities and dangerous outdoor work at height, and by yellow it adds large indoor and outdoor gatherings. If your plan is a boat trip, a coastal walk or an open-air attraction, a blue or yellow typhoon signal is already your cue.
Typhoon blue & yellow defence guides
Source: China Meteorological Administration (中国气象局), www.cma.gov.cn — 台风预警信号 (Typhoon warning signals) — colour standards and defence guides (read July 25, 2026)
In short
Warning-signal questions travellers ask
What the colours mean, when things close, and the train-and-flight question everyone gets wrong.
What do the blue, yellow, orange and red weather warnings in China mean?
They are the four levels of one national warning-signal ladder: blue is Level IV (general), yellow Level III (relatively severe), orange Level II (severe) and red Level I (especially severe). Blue is the lowest and red the highest, per the China Meteorological Administration's issuance rule.
Is the colour system the same for a typhoon, a heatwave and a cold snap?
Yes. The CMA rule uses the same blue-to-red scheme for every hazard type it lists — typhoon, rainstorm, snowstorm, cold wave, gale, high temperature, haze, road icing and more. Learn the one ladder and it reads across all of them; a red high-temperature signal and a red typhoon signal are both the top rung.
At what point do things actually close?
For the typhoon signal, the officially published defence guides tell open-air group activity and dangerous work at height to stop from blue, add large gatherings by yellow, and suspend classes and business (except special industries) from orange and red. So the widespread closures a traveller notices start at typhoon orange.
Does a red signal automatically stop the trains and flights?
Not automatically, but three red signals do name transport. Read on 22 August 2026, the CMA defence guides say: at dense-fog red, relevant units take traffic-safety control measures as appropriate under their industry rules, the guide's own examples being aircraft suspended, expressways closed and ferries halted; at snowstorm red, aircraft, trains and expressways stop when necessary (必要时); and at sandstorm red the guide states flatly that aircraft stop taking off and landing, trains stop running and expressways temporarily close. Two of the three carry a hedge, and no other hazard or colour names rail or air at all — a red typhoon or rainstorm signal closes classes and business, not your flight. So check 12306 for your train and your carrier for your flight rather than reading the colour as a cancellation.
Which weather warning colour closes shops, offices and schools in China?
Orange is the first rung that closes anything broadly, and it is scoped differently by hazard. Typhoon orange suspends large gatherings, classes and business except special industries. Rainstorm orange suspends classes and business only for units in danger zones, and gale orange only for schools and units whose buildings resist wind poorly. Red widens it: typhoon red and rainstorm red stop gatherings, classes and business outright except special industries; snowstorm red does so when necessary. High-temperature red stops open-air outdoor work only, and road icing closes no business at any rung.
Where will I see the warning signal?
Signals are broadcast widely — weather apps, TV, station and scenic-area boards. The CMA rule requires the name, icon, standard and defence guide, marked in Chinese and English, so the colour and its level are the part you can read at a glance even without the Chinese text.
Not confirmed
What no opened source would let us say
The claims we could not source from a page we opened are printed here rather than asserted.
- Superseded on 2026-08-22, and recorded here rather than quietly deleted: this guide used to say no opened source tied any colour to a rail or air suspension. Opening the seven remaining CMA threshold pages showed three that do — fog red, snowstorm red and sandstorm red — and the table above now carries them with their hedges intact. What is still not sourced is any rule making those suspensions automatic, or any threshold at which an individual train or flight must be cancelled: that call stays with the railway and the carrier, so 12306 and your airline remain the places to check.
- The transcribed standards and defence guides are the CMA portal's own wording for each hazard. Provincial and municipal meteorological services may issue on locally-adjusted thresholds, and a city's emergency plan can close things the national defence guide does not name — the Beijing heavy-air-pollution plan cited elsewhere on this site is one such case. Nothing here was checked against a provincial standard.
- The high-temperature and cold-wave signals are named rungs of this same CMA ladder, so they are covered here as part of the one scheme. No distinct official heat-health or cold-wave traveller advisory was opened, so this guide does not add health instructions beyond what the warning-signal rule itself carries.
- Eight hazards now carry their full colour-by-colour thresholds on this page: rainstorm, typhoon, dense fog, snowstorm, sandstorm, high temperature, gale and road icing. The remaining signals in the CMA scheme — cold wave, lightning, hail, drought, frost and haze — were not opened this pass, so this guide does not state their thresholds. Read the signal's own defence guide when one of those is issued for the hazard you face.
If your flight is delayed or cancelled
The airline-side delay and cancellation flow — what you are owed and what to do at the airport.
Open the guideA heavy air-pollution red alert
What an AQI red alert actually closes — schools, outdoor sites and half the cars on the road.
Open pageAll the recovery guides
Every in-trip recovery guide in one place, from a lost passport to a shut-down trip.
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