Illinois Weather Forecast
Illinois weather: 59°F, clear. Hourly forecast, 14-day outlook, UV, air quality and the best time to visit.
Risk assessment for Illinois
Derived from the current forecast window - not an official warning.
Peak gusts of 37 mph and 0 thunderstorm days in the next 16 days.
Wettest single day forecast at 0,6 in, 2,1 in across the window. Flash flooding risk rises sharply above 50 mm in a day.
Active alerts for Illinois
Derived from the forecast. No official alert feed is wired for this country yet.
16-day forecast for Illinois
Daily highs and lows, precipitation and UV.
| Day | Conditions | High / Low | Precip | Wind | UV |
|---|---|---|---|---|---|
| Tue, Aug 25 | ☁️ Overcast | 84° / 57° | 2% | 6 mph | 7 |
| Wed, Aug 26 | ☁️ Overcast | 90° / 67° | 39% | 10 mph | 7 |
| Thu, Aug 27 | ☀️ Clear sky | 85° / 63° | 7% | 13 mph | 7 |
| Fri, Aug 28 | ☁️ Overcast | 83° / 61° | 1% | 9 mph | 7 |
| Sat, Aug 29 | ☁️ Overcast | 79° / 61° | 1% | 11 mph | 4 |
| Sun, Aug 30 | ☁️ Overcast | 95° / 68° | 8% | 15 mph | 7 |
| Mon, Aug 31 | 🌧️ Heavy drizzle | 85° / 68° | 14% · 0,2 in | 10 mph | 3 |
| Tue, Sep 1 | 🌦️ Light showers | 88° / 68° | 14% · 0,6 in | 10 mph | 6 |
| Wed, Sep 2 | 🌦️ Drizzle | 95° / 70° | 15% · 0,2 in | 10 mph | 7 |
| Thu, Sep 3 | 🌦️ Drizzle | 95° / 72° | 17% · 0,1 in | 14 mph | 7 |
| Fri, Sep 4 | 🌦️ Light drizzle | 95° / 76° | 17% · 0,0 in | 16 mph | 6 |
| Sat, Sep 5 | 🌦️ Light drizzle | 87° / 67° | 24% · 0,1 in | 15 mph | 4 |
| Sun, Sep 6 | 🌦️ Light showers | 66° / 55° | 30% · 0,5 in | 14 mph | 1 |
| Mon, Sep 7 | ☁️ Overcast | 71° / 54° | 34% | 10 mph | 4 |
| Tue, Sep 8 | 🌦️ Light rain | 62° / 56° | 19% · 0,4 in | 10 mph | 1 |
| Wed, Sep 9 | ☀️ Clear sky | -- / -- | 29% | -- | — |
What this means for Illinois
Today is about average for August. The forecast high of 84°F is in line with the 83°F typical for this month.
Rain is very unlikely today - plans do not need a backup.
No weather-related travel disruption is expected today. Roads and airports should run normally.
Northern Hemisphere, so peak summer falls in June to August.
The gap between the warmest and coldest month averages 83°F.
See the Illinois forecast by time range
Illinois weather - more answers
Explore Illinois
Every topic we hold for this place, and the same topic for the places around it.
Weather for related places
Frequently asked questions
Where is Illinois?
Illinois is a state in United States. Its coordinates are 39.7817, -89.6501. It lies in North America.
What is the weather like in Illinois right now?
It is currently 59°F (15°C) with clear. Humidity is 90% and wind is 3 mph.
When is the best time to visit Illinois?
August, September and October offer the most comfortable conditions in Illinois, which has a continental climate. January, February and December 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 7:31 AM.
How many people live in Illinois?
Illinois has a population of approximately 12.6 million.
What is the nearest airport to Illinois?
The closest airports are O'Hare International Airport (ORD), 177 mi away and Nashville International Airport (BNA), 300 mi away.
What are the top things to 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. |
|---|---|
| Forecast and observations | Open-Meteo (ECMWF and national models). |
| Air quality and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| Climate averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National Weather 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 August 25, 2026 at 7:31 AM local time. Live blocks refresh every 15 minutes; climate averages monthly.
