What a Cwa climate is like
Cwa Humid subtropical with dry winter. A monsoon-influenced subtropical climate. Most of the rain falls in the hot summer, and winters are noticeably drier.
The rules behind the code, in plain English:
- Temperate (coldest month between 0 °C and 18 °C).
- Dry winter: the driest winter month gets less than a tenth of the rain of the wettest summer month.
- Hot summer: the warmest month averages 22 °C or more.
Dataset wording: "Temperate, dry winter, hot summer". In the maps of Beck et al. (2023) the class is written: C: Not B and Thot > 10 and 0 < Tcold < 18; w: Pwdry < Pswet/10; a: Thot >= 22.
Humid subtropical climate with a dry winter has hot, wet summers and mild, dry winters, so the rain arrives in the same season as the heat. Summers are sticky and storm-filled, while winter skies are clearer and the air is drier. Rice, tea, sugar cane and other warm-season crops do well, and forests are broadleaf and evergreen. Light clothes suit most of the year, with a warmer layer for the cool, dry months.
How much of the world is Cwa?
- 3%of the world's land outside Antarctica, 1991 to 2020
- 4,089,974 km²area, 1991 to 2020
- 2,414cities of 15,000 or more people (GeoNames) have this climate now
In 1901 to 1930 it covered 3.3% of that land, so its area then was 8.21% larger than in 1991 to 2020.
How the Cwa area is projected to change by 2071 to 2099
These figures compare the area of Cwa in each future map with 1991 to 2020. They come from the Beck et al. (2023) model projections under three emissions scenarios. They show what the scenarios imply, not what will happen.
| Map | Share of land | Change in area vs 1991 to 2020 |
|---|---|---|
| 1901 to 1930 (past) | 3.3% | +8.21% |
| 1991 to 2020 (now) | 3% | - |
| 2071 to 2099, SSP1-2.6 (low emissions) | 2.5% | -18.58% |
| 2071 to 2099, SSP2-4.5 (middle of the road) | 2% | -33.17% |
| 2071 to 2099, SSP5-8.5 (high emissions) | 1.8% | -42.18% |
Shares are of land outside Antarctica. A negative change means the zone shrinks.
What happens to today's Cwa land
Of the land that is Cwa in 1991 to 2020, this is how much stays Cwa and where the rest ends up in 2071 to 2099, by scenario:
| Scenario (2071 to 2099) | Stays Cwa | Where the rest goes (biggest first) |
|---|---|---|
| SSP1-2.6, low emissions | 64% | Aw (24%), Cfa (4.8%), Am (4.4%), BSh (2.8%) |
| SSP2-4.5, middle of the road | 44% | Aw (43%), Am (5.4%), BSh (4.5%), Cfa (3.4%) |
| SSP5-8.5, high emissions | 28% | Aw (52%), Am (9%), BSh (7.9%), Cfa (2.3%) |
Looking back, 84% of today's Cwa land was also Cwa in 1901 to 1930. The rest was Cwb (5.7%), Cfa (3.8%), BSh (2.7%), Dwa (2%), BSk (0.9%).
Where Cwa is found
The countries with the most Cwa land in 1991 to 2020:
| Country | Area | Share of all Cwa | Share of the country |
|---|---|---|---|
| India | 924,744 km² | 23% | 29% |
| China | 823,238 km² | 20% | 8.8% |
| Zambia | 418,881 km² | 10% | 56% |
| Angola | 259,199 km² | 6.3% | 21% |
| Argentina | 250,595 km² | 6.1% | 9% |
| Myanmar | 247,286 km² | 6.1% | 37% |
| Vietnam | 138,470 km² | 3.4% | 42% |
| Mexico | 127,600 km² | 3.1% | 6.5% |
Places with a Cwa climate today
The biggest cities in the 1991 to 2020 map that sit in Cwa (at most two per country):
Other temperate climates (group C)
Frequently asked questions
What does Cwa mean in the Köppen climate classification?
Temperate (coldest month between 0 °C and 18 °C). Dry winter: the driest winter month gets less than a tenth of the rain of the wettest summer month. Hot summer: the warmest month averages 22 °C or more. The code is a short way of writing that: the first letter is the major group (C, temperate) and the letters after it say more about rain and temperature.
What is a humid subtropical with dry winter climate like?
Hot, wet summers and dry, mild winters. A monsoon-influenced subtropical climate. Most of the rain falls in the hot summer, and winters are noticeably drier.
How much of the world has a Cwa climate?
3% of the world's land outside Antarctica was Cwa in 1991 to 2020, about 4,089,974 km² (Beck et al. 2023, 1 km maps).
Will the Cwa climate zone grow or shrink?
Under the middle-of-the-road scenario (SSP2-4.5), the area of Cwa in 2071 to 2099 is 33.17% smaller than in 1991 to 2020. This is a model projection, not a forecast, and it differs under other scenarios (see the table on this page).
Data: Beck et al. (2023), CC BY 4.0. See data sources and licences. Köppen-Geiger classes describe long-term averages, not weather.