Illinois Wetter Vorhersage
Illinois weather: 17°C, klar. Stündlich forecast, 14-day outlook, UV, air quality and the best time und visit.
Illinois weather in August
One of the best months und visit Illinois.
August runs 10°C warmer than the annual average in Illinois.
Compare mit September.
Wetter map for Illinois
Animated model layers. Pick a layer und load it.
Animated layers by Windy. For pin-level detail and nearby places, see the interactive map below.
Klima in Illinois month by month
Average high, average low and total rainfall, based on three years of reanalysis data.
| Monat | Durchschnittliches Maximum | Durchschnittliches Minimum | Niederschlag | Bewertung |
|---|---|---|---|---|
| Januar | 1° | -7° | 62 mm | ★★☆☆☆ |
| Februar | 8° | -3° | 20 mm | ★★★☆☆ |
| März | 15° | 4° | 90 mm | ★★★☆☆ |
| April | 19° | 9° | 135 mm | ★★★☆☆ |
| Mai | 24° | 13° | 100 mm | ★★★★☆ |
| Juni | 28° | 19° | 117 mm | ★★★★☆ |
| Juli | 29° | 21° | 129 mm | ★★★★☆ |
| August | 29° | 19° | 75 mm | ★★★★☆ |
| September | 28° | 17° | 33 mm | ★★★★★ |
| Oktober | 20° | 10° | 37 mm | ★★★★☆ |
| November | 12° | 4° | 79 mm | ★★★☆☆ |
| Dezember | 6° | -2° | 62 mm | ★★☆☆☆ |
Klima type: Kontinental. Quelle: Open-Meteo archive (ERA5).
Beste Reisezeit Illinois
Go in August, September and Oktober. These months score highest on comfortable temperatures, low rainfall and useful daylight.
Hardest months: Januar, Februar and Dezember – expect the least comfortable mix of heat, cold or rain.
What und pack, what und skip
- Lightweight, light-coloured clothing and a refillable water bottle
- So.glasses, a brimmed hat and SPF 30+
- Layers – the daily swing is 23°C, so mornings feel nothing like afternoons
- If your dates are flexible, avoid Januar, Februar and Dezember – historically the least comfortable months here.
How Illinois compares mit 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 |
Vorhersage für Illinois nach Zeitraum ansehen
Illinois weather – more answers
Explore Illinois
Every topic we hold for this place, and the same topic for the places around it.
Wetter for related places
Frequently asked questions
Where is Illinois?
Illinois is a state in Vereinigte Staaten. Its coordinates are 39.7817, -89.6501. It lies in Nordamerika.
What is the weather like in Illinois jetzt?
It is currently 17°C (62°F) mit klar. Luftfeuchtigkeit is 45% and wind is 5 km/h.
When is the best time und visit Illinois?
August, September and Oktober offer the most comfortable conditions in Illinois, which has a continental climate. Januar, Februar and Dezember are usually the hardest months for outdoor plans.
What time zone is Illinois in?
Illinois observes America/Chicago (UTC-05:00). The Ortszeit is 10:45 PM.
How many people live in Illinois?
Illinois has a population of approximately 12.6 million.
What is the nearest airport und 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 und 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. |
|---|---|
| Vorhersage and observations | Open-Meteo (ECMWF and national models). |
| Luftqualität and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| Klima averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National Wetter 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 Oktober 5, 2026 at 10:45 PM Ortszeit. Live blocks refresh every 15 minutes; climate averages monthly.
