Illinois 气候 and Average 天气
气候 of Illinois: average temperatures, rainfall and seasons month by month.
气候 in Illinois month by month
Average high, average low and total rainfall, based on three years of reanalysis data.
| 月份 | Avg high | Avg low | 雨fall | Rating |
|---|---|---|---|---|
| 一月 | 1° | -7° | 62 mm | ★★☆☆☆ |
| 二月 | 8° | -3° | 20 mm | ★★★☆☆ |
| 三月 | 15° | 4° | 90 mm | ★★★☆☆ |
| 四月 | 19° | 9° | 135 mm | ★★★☆☆ |
| 五月 | 24° | 13° | 100 mm | ★★★★☆ |
| 六月 | 28° | 19° | 117 mm | ★★★★☆ |
| 七月 | 29° | 21° | 129 mm | ★★★★☆ |
| 八月 | 28° | 19° | 47 mm | ★★★★☆ |
| 九月 | 27° | 16° | 42 mm | ★★★★☆ |
| 十月 | 20° | 10° | 37 mm | ★★★★☆ |
| 十一月 | 12° | 4° | 79 mm | ★★★☆☆ |
| 十二月 | 6° | -2° | 62 mm | ★★☆☆☆ |
气候 type: 大洲al. 来源： Open-Meteo archive (ERA5).
Recent extremes in Illinois
高est and lowest readings observed in the last 3 years of reanalysis data - not all-time records.
How Illinois compares，天气为nearby places
Annual averages, and the difference against Illinois.
| Place | Distance | Avg temp | vs here | Annual rain |
|---|---|---|---|---|
| Gateway Arch National Park | 137 km | 15°C | +1°C warmer | 1144 mm |
| St. Louis | 137 km | 15°C | +1°C warmer | 1144 mm |
| Missouri | 255 km | 14°C | +1°C warmer | 1002 mm |
| Indianapolis | 298 km | 13°C | 1°C cooler | 1094 mm |
| Indiana | 298 km | 13°C | 1°C cooler | 1094 mm |
气候 by city in Illinois
1 cities mapped in this atlas
气候 by state park in Illinois
1 state and provincial parks mapped in this atlas
气候 by county in Illinois
1 counties mapped in this atlas
气候 by lake in Illinois
1 lakes mapped in this atlas
最佳旅游时间 Illinois
Go in 八月, 九月 and 十月. These months score highest on comfortable temperatures, low rainfall and useful daylight.
Hardest months: 一月, 二月 and 十二月 - expect the least comfortable mix of heat, cold or rain.
What this means for Illinois
Today is slightly warmer than average for 八月. The forecast high of 31°C is 2.2°C above the 28°C typical for this month.
A 10% chance means most of the area stays dry; a passing shower is possible but short.
No weather-related travel disruption is expected today. Roads and airports should run normally.
Northern Hemisphere, so peak summer falls in 六月至八月.
The gap between the warmest and coldest month averages 29°C.
What至pack, what至skip
- Lightweight, light-coloured clothing and a refillable water bottle
- 周日glasses, a brimmed hat and SPF 30+
- If your dates are flexible, avoid 一月, 二月 and 十二月 - historically the least comfortable months here.
摘要
Illinois is a state in 美国. Illinois is a US state，首都是Springfield. 人口约为12.6 million. 首都是Springfield.
目前气温为17°C (63°F) in Illinois，天气为晴. 体感温度为18°C. 今天气温在16°C至31°C. 降水概率为10%. Sightseeing conditions score 9.7/10 - 极佳 — 现在适合出行.
最佳旅游时间是Illinois is 八月, 九月 and 十月. 气候为continental. 一月, 二月 and 十二月 tend至be the least comfortable months. 七月 is the warmest month，天气为average highs near 29°C, while 一月 is the coldest，天气为lows near -7°C.
The closest major airport is O'Hare International Airport (ORD), about 284 km away. Nearby highlights include Starved Rock State Park, Lake Michigan, Gateway Arch National Park and Indiana Dunes National Park.
简单来说。 Today is slightly warmer than average for 八月. The forecast high of 31°C is 2.2°C above the 28°C typical for this month. The best window至be outside is roughly 8 AM至11 AM, when temperature, rain chance and wind line up best. sightseeing is the strongest bet in Illinois today at 9.7/10. No weather-related travel disruption is expected today. Roads and airports should run normally.
Compiled from this page's own data: atlas facts plus live Open-Meteo readings.
Quick facts about Illinois
天气 map for Illinois
Animated model layers. Pick a layer至load it.
Animated layers by 风y. For pin-level detail and nearby places, see the interactive map below.
Explore Illinois
Every topic we hold for this place, and the same topic for the places around it.
气候 for related places
Frequently asked questions
Where is Illinois?
Illinois is a state in 美国. Its coordinates are 39.7817, -89.6501. It lies in 北美洲.
What is the weather like in Illinois现在?
It is currently 17°C (63°F)，天气为晴. 湿度 is 78% and wind is 3 km/h.
When is the best time至visit Illinois?
八月, 九月 and 十月 offer the most comfortable conditions in Illinois, which has a continental climate. 一月, 二月 and 十二月 are usually the hardest months for outdoor plans.
What time zone is Illinois in?
Illinois observes America/Chicago (UTC-05:00). The local time is 4:41 AM.
How many people live in Illinois?
Illinois has a population of approximately 12.6 million.
What is the nearest airport至Illinois?
The closest airports are O'Hare International Airport (ORD), 284 km away and Nashville International Airport (BNA), 483 km away.
What are the top things至do in Illinois?
Popular options include Starved Rock State Park, Lake Michigan, Gateway Arch National Park and Indiana Dunes National Park.
What places are in Illinois?
Illinois covers 4 places in this atlas, including Chicago, Starved Rock State Park, Cook County and Lake Michigan.
Related articles
Data sources and methodology
| Place data | USPOTUS Atlas dataset (us-states) - coordinates, hierarchy and facts. |
|---|---|
| 预报 and observations | Open-Meteo (ECMWF and national models). |
| 空气质量 and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| 气候 averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National 天气 Service. |
| Method | Scores, comparisons and advice on this page are computed from the inputs above. Distances are straight-line. Nothing is estimated where data is missing - the block is simply not shown. |
Last updated 八月 21, 2026 at 4:41 AM local time. Live blocks refresh every 15 minutes; climate averages monthly.
