Illinois 天氣 預報
Illinois weather: 18°C, 晴朗. 逐小時 forecast, 14-day outlook, UV, air quality and the best time至visit.
氣候 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 | 29° | 19° | 75 mm | ★★★★☆ |
| 九月 | 28° | 17° | 33 mm | ★★★★★ |
| 十月 | 20° | 10° | 37 mm | ★★★★☆ |
| 十一月 | 12° | 4° | 79 mm | ★★★☆☆ |
| 十二月 | 6° | -2° | 62 mm | ★★☆☆☆ |
氣候 type: 洲al. 來源： Open-Meteo archive (ERA5).
最佳旅遊時間 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.
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，天氣為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 | 1156 mm |
| St. Louis | 137 km | 15°C | +1°C warmer | 1156 mm |
| Missouri | 255 km | 15°C | +1°C warmer | 1006 mm |
| Indianapolis | 298 km | 13°C | 1°C cooler | 1135 mm |
| Indiana | 298 km | 13°C | 1°C cooler | 1135 mm |
What至pack, what至skip
- 週日glasses, a brimmed hat and SPF 30+
- Layers - the daily swing is 19°C, so mornings feel nothing like afternoons
- If your dates are flexible, avoid 一月, 二月 and 十二月 - historically the least comfortable months here.
查看 Illinois 的分時預報
Illinois weather - more answers
Explore Illinois
Every topic we hold for this place, and the same topic for the places around it.
天氣 for related places
Frequently asked questions
Where is Illinois?
Illinois is a state in 美國. Its coordinates are 39.7817, -89.6501. It lies in 北美洲.
What is the weather like in Illinois現在?
It is currently 18°C (64°F)，天氣為晴朗. 濕度 is 39% and wind is 8 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 8:41 PM.
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. |
|---|---|
| 預報 and observations | Open-Meteo (ECMWF and national models). |
| 空氣品質 and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| 氣候 averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National 天氣 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 十月 24, 2026 at 8:41 PM local time. Live blocks refresh every 15 minutes; climate averages monthly.
