Illinois Loftslag and Average Veður
Loftslag of Illinois: average temperatures, rainfall and seasons month by month.
Loftslag in Illinois month by month
Average high, average low and total rainfall, based on three years of reanalysis data.
| Mánuður | Avg high | Avg low | Rigningfall | Rating |
|---|---|---|---|---|
| janúar | 1° | -7° | 62 mm | ★★☆☆☆ |
| febrúar | 8° | -3° | 20 mm | ★★★☆☆ |
| mars | 15° | 4° | 90 mm | ★★★☆☆ |
| apríl | 19° | 9° | 135 mm | ★★★☆☆ |
| maí | 24° | 13° | 100 mm | ★★★★☆ |
| júní | 28° | 19° | 117 mm | ★★★★☆ |
| júlí | 29° | 21° | 129 mm | ★★★★☆ |
| ágúst | 29° | 19° | 75 mm | ★★★★☆ |
| september | 28° | 17° | 33 mm | ★★★★★ |
| október | 20° | 10° | 37 mm | ★★★★☆ |
| nóvember | 12° | 4° | 79 mm | ★★★☆☆ |
| desember | 6° | -2° | 62 mm | ★★☆☆☆ |
Loftslag type: Heimsálfaal. Heimild: Open-Meteo archive (ERA5).
Recent extremes in Illinois
Háttest and lowest readings observed in the last 3 years of reanalysis data - not all-time records.
How Illinois compares með 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 |
Loftslag by city in Illinois
1 cities mapped in this atlas
Loftslag by state park in Illinois
1 state and provincial parks mapped in this atlas
Loftslag by county in Illinois
1 counties mapped in this atlas
Loftslag by lake in Illinois
1 lakes mapped in this atlas
Best time til visit Illinois
Go in ágúst, september and október. These months score highest on comfortable temperatures, low rainfall and useful daylight.
Hardest months: janúar, febrúar and desember - expect the least comfortable mix of heat, cold or rain.
What this means for Illinois
Today is warmer than average for október. The forecast high of 25°C is 5.1°C above the 20°C typical for this month.
Rigning 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 júní til ágúst.
The gap between the warmest and coldest month averages 29°C.
What til pack, what til skip
- sun.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 janúar, febrúar and desember - historically the least comfortable months here.
Samantekt
Illinois is a state in Bandaríkin. Illinois is a US state með höfuðborg í Springfield. Íbúafjöldinn er um 12.6 million. Höfuðborgin er Springfield.
Núna er hitinn 14°C (57°F) in Illinois með að mestu heiðskýrt. Hitinn finnst vera 13°C. Í dag er hitinn frá 7°C til 25°C. Líkur á úrkomu eru 0%. Sightseeing conditions score 9.6/10 - frábært — farðu núna.
Besti tíminn til að heimsækja Illinois is ágúst, september and október. Loftslagið er continental. janúar, febrúar and desember tend til be the least comfortable months. júlí is the warmest month með average highs near 29°C, while janúar is the coldest með 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.
Í einföldu máli. Today is warmer than average for október. The forecast high of 25°C is 5.1°C above the 20°C typical for this month. The best window til be outside is roughly 11 AM til 2 PM, when temperature, rain chance and wind line up best. hiking is the strongest bet in Illinois today at 9.8/10. 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
| Tegund | State |
|---|---|
| Land | Bandaríkin |
| Heimsálfa | Norður-Ameríka |
| Hnit | 39°46′54.1″N 89°39′0.4″W (39.7817, -89.6501) |
| Capital | Springfield |
| Mannfjöldi | 12.600.000 |
| Area | 149.995 km² |
| Abbreviation | IL |
| Tímabelti | America/Chicago |
| Staðartími | 3:58 PM (UTC-05:00) |
| Best months | ágúst, september and október |
| Loftslag | Heimsálfaal |
Veður map for Illinois
Animated model layers. Pick a layer til load it.
Animated layers by Vindury. 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.
Loftslag for related places
Frequently asked questions
Where is Illinois?
Illinois is a state in Bandaríkin. Its coordinates are 39.7817, -89.6501. It lies in Norður-Ameríka.
What is the weather like in Illinois núna?
It is currently 14°C (57°F) með að mestu heiðskýrt. Raki is 71% and wind is 7 km/h.
When is the best time til visit Illinois?
ágúst, september and október offer the most comfortable conditions in Illinois, which has a continental climate. janúar, febrúar and desember 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 3:58 PM.
How many people live in Illinois?
Illinois has a population of approximately 12.6 million.
What is the nearest airport til 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 til 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. |
|---|---|
| Spá and observations | Open-Meteo (ECMWF and national models). |
| Loftgæði and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| Loftslag averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National Veður 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 október 26, 2026 at 3:58 PM local time. Live blocks refresh every 15 minutes; climate averages monthly.
