China's Blue, Yellow, Orange and Red Weather Warnings Explained

Direct answer: mainland China warns in four colours: blue, yellow, orange and red, with red the most serious. Each colour also carries a level written in Roman numerals, and the numbers run the opposite way to what most readers expect: Level I is the highest, not the lowest. Hong Kong does not use this ladder for rain at all; it has its own amber, red and black rainstorm signals.

The four colours, and why “Level I” is the top

China’s government describes its weather warning system as four tiers, with red the most severe, followed by orange, yellow and blue. The warnings this site receives from Chinese meteorological observatories print the level beside the colour, and on the days this was written they read consistently:

• Red — Level I. “Xinyi Meteorological Station issued rainstorm red warning [Level I/especially serious]”.
• Orange — Level II. “Taishan Meteorological Station issued an orange rainstorm warning [Level II/severe]”.
• Yellow — Level III. Dozens a day, for rain, fog, lightning and wind.
• Blue — Level IV, the lowest of the four.

The trap is the numbering. In most rankings people meet, “level one” is the entry level and higher numbers are worse. Here it is the reverse. A headline that says a city has raised its warning to Level I is describing the most serious warning the system has, and a warning “lowered to Level IV” has been reduced to the mildest.

Warning level and emergency response level are two different things

China runs two four-tier scales that both count down to Level I, and news reports mention them in the same paragraph:

• A weather warning is the forecast: this colour of rain, fog or wind is expected here.
• An emergency response level is the level of preparation government bodies have switched on in reply.

They move separately. The China Meteorological Administration has, for example, lowered its emergency response for rainstorm-related disasters from Level III to Level IV on a day when blue and yellow alerts were still being issued for other regions. Reading a response level as a warning, or the other way round, is an easy way to misread a Chinese weather story.

Who issues them: often a single county

Warnings are not only national. Most of the Chinese warnings in this site’s feed come from district and county observatories — Shunde District, Xinhui District, Longling County — each covering a small area. Two practical consequences follow:

• A red warning in one district says nothing about the district next to it, which may hold yellow or nothing.
• Many warnings are later lifted. A notice that an observatory “lifts the yellow warning” means the warning has ended, not that a new one has begun.

The same colour covers very different hazards

One ladder is used across hazards. On a single day the feed carried red warnings for rainstorms and for heavy fog, orange warnings for forest and grassland fire risk, and yellow warnings for lightning, thunderstorms with strong winds and geological hazard risk — landslides and debris flows. The colour tells you how serious the observatory judges the situation; only the hazard word tells you what to do about it. A red fog warning is about roads and visibility, not water.

The severity words after the numeral are translations and vary: the same Level III appears as “heavy” in one warning and “severe” in the next. Trust the colour and the numeral, not the English adjective.

Hong Kong is different

Hong Kong’s Observatory runs its own rainstorm warning system with three signals, defined by how much rain has fallen or is expected across the territory in an hour:

• Amber — more than 30 mm in an hour. An alert that conditions may develop into red or black; flooding in some low-lying and poorly drained places.
• Red — more than 50 mm in an hour. Serious road flooding and traffic congestion are likely.
• Black — more than 70 mm in an hour. Stay indoors or take shelter in a safe place until the heavy rain has passed.

Two things to carry from this. First, Hong Kong’s red is not the top of its scale — black is — so “red” means something different on either side of the boundary. Second, the Observatory says the rainstorm signals are independent of its tropical cyclone and landslip warnings, which are issued separately. A rainstorm signal and a tropical cyclone warning are separate messages, and each needs reading on its own terms.

How to read one in ten seconds

1. Where was it issued? Mainland observatory or Hong Kong Observatory — they use different ladders.
2. Colour and numeral. On the mainland, red and Level I are the top. In Hong Kong, black is the top.
3. Issued, updated or lifted? The verb matters as much as the colour.
4. Which hazard? Rain, fog, fire risk and lightning share colours and need different actions.
5. Which area? Often one district, not a province.

How this site shows them

We carry these warnings as the observatories issued them, through the WMO Alert Hub, with the original colour and level left in the title. On our own severity scale a red warning is shown as extreme, orange as severe and yellow as moderate. The observatory’s wording is the authority; for instructions, follow the China Meteorological Administration, the local observatory named in the warning, or in Hong Kong the Hong Kong Observatory.

Related reading: what alert colours mean in other countries, why an extreme warning is not always about something already happening, and why a weather app is not an official warning.

Frequently asked questions

What is the highest weather warning in China?

Red, which carries Level I. China uses four warning colours - blue, yellow, orange and red - and red is the most severe. The levels are written in Roman numerals and count down, so Level I is the top and Level IV the lowest.

Is Level I the lowest or the highest level?

The highest. In Chinese weather warnings red is Level I, orange Level II and yellow Level III. The same counting-down applies to China's emergency response levels, where Level I is the most serious response.

Is a warning level the same as an emergency response level?

No. A warning is the forecast of a hazard in an area; an emergency response level is what government agencies have activated in reply. Both have four tiers with Level I at the top, and they change independently of each other.

How is Hong Kong's rainstorm warning different?

Hong Kong uses three signals of its own - amber for more than 30 mm of rain an hour, red for more than 50 mm and black for more than 70 mm. Black is the top, so Hong Kong's red is not its most serious signal. Under a black signal the Observatory tells people to stay indoors or take shelter.

Sources

• The State Council of the People's Republic of China (Xinhua) - China renews alerts for rainstorms, mountain torrents, geological disasters
• Hong Kong Observatory - Rainstorm Warning System

Found an error? See our corrections policy.