Illinois, United States Weather

  1. Illinois, United States Weather
  2. Current conditions
  3. Weather forecast
  4. Averages and extremes
  5. Yesterday's Data
  6. Temperature and possibility of rain in Illinois over the next 12 hours
  7. Temperature and possibility of rain in Illinois in the coming days
  8. Rainfall in Illinois in the coming days
  9. Illinois Weather Summary
  10. Weather averages by month
  11. Illinois's weather
  12. Frequently asked questions
  13. Comments
Illinois, Weather
(Photo by Anthony Fomin on Unsplash)

Current conditions

Updated:
18°C
64.4°F
°C °F

Condition: Overcast

Pressure: 980 hPa

Feel like: 15 °C

Temperature: 18°C

Cloud: 100%

Humidity: 85%

Wind: S - 32 km/h

Visibility: 15.4 km

Weather forecast

Wed
04 Nov
11°C / 16°C
Drizzle Dense Intensity
Thu
05 Nov
8°C / 16°C
Overcast
Fri
06 Nov
4°C / 11°C
Overcast
Sat
07 Nov
2°C / 10°C
Overcast
Sun
08 Nov
3°C / 14°C
Overcast
Hourly forecast today:
17:00 PM
15° / 18°
15° / 18°
Overcast
85% 63 km/h
18:00 PM
16° / 19°
16° / 19°
Overcast
79% 62 km/h
19:00 PM
16° / 19°
16° / 19°
Overcast
80% 65 km/h
20:00 PM
15° / 19°
15° / 19°
Overcast
79% 68 km/h
21:00 PM
16° / 20°
16° / 20°
Overcast
76% 73 km/h
22:00 PM
15° / 20°
15° / 20°
Overcast
74% 71 km/h
23:00 PM
15° / 20°
15° / 20°
Overcast
74% 66 km/h
00:00 AM
15° / 20°
15° / 20°
Overcast
75% 74 km/h
01:00 AM
17° / 18°
17° / 18°
Drizzle Dense Intensity
94% 72 km/h
02:00 AM
17° / 18°
17° / 18°
Overcast
92% 59 km/h
03:00 AM
17° / 18°
17° / 18°
Overcast
92% 74 km/h

30 Day Averages and Extremes

  • Average high 18.43°C
  • Average low 7.97°C
  • Hottest day 25°C (28 October 2026)
  • Coldest day 2°C (07 November 2026)
  • Average humidity 66.47%
  • Days with precipitation 17 days
  • Highest precipitation 26 mm (03 November 2026)

Yesterday's Data

  • Max: 17°C
  • Min: 12°C
  • Total Precipitation: 0 mm

Temperature and possibility of rain in Illinois over the next 12 hours

Temperature and possibility of rain in Illinois in the coming days

Rainfall in Illinois in the coming days

Illinois Climate Summary

Illinois features a Humid continental, no dry season, hot summer (Köppen classification: Dfa), with an average annual temperature of 12.07ºC (53.73ºF), which is about -0.57% lower than the national average for United States. Annually, the city experiences approximately 38.16 millimeters (1.5 inches) of rainfall, spread across 87.73 rainy days, accounting for 24.04% of the year.

Longitude 40.6331249
Latitude -89.3985283
Yearly high temperature 15.14ºC (59.25ºF)
Yearly low temperature 6.9ºC (44.42ºF)
Hottest month July 27.72ºC (81.9ºF)
Coldest month January -7.09ºC (19.24ºF)
Yearly precip 38.16mm (1.5in)
Days with rainfall 87.73 days (24.04%)
Driest month December (78.37%)
Wettest month May (77.38%)

Weather averages by month

Month High / Low (°C) Rain
January -1.0° / -7.09° 3.82 days
February 1.4° / -5.63° 4.73 days
March 9.03° / 1.17° 6.45 days
April 15.53° / 6.66° 9.0 days
May 22.0° / 13.0° 12.64 days
June 26.49° / 17.26° 10.55 days
July 27.72° / 18.69° 10.91 days
August 27.14° / 17.47° 7.73 days
September 24.45° / 14.28° 7.09 days
October 17.23° / 8.28° 6.36 days
November 8.89° / 1.57° 4.45 days
December 2.76° / -2.82° 4.0 days

Illinois's weather

Frequently asked questions

1. What is the hottest month in Illinois?

July has the highest average monthly temperature (daily mean of 27.72ºC) and January are the coolest (daily mean of -7.09ºC).

2. What should I wear in Illinois today?

For today's warm weather in Illinois, with temperatures between 17ºC to 20ºC (62.6ºF to 68.0ºF), you might consider wearing:
- Light, breathable socks
- Cotton or linen fabrics
- T-shirt or short-sleeve blouse
- Sun hat or cap

Temperature

Early
16°C / 16°C
Morning
13°C / 15°C
Afternoon
15°C / 18°C
Evening
16°C / 20°C

Air quality

Good

Satisfactory air quality, minimal pollution, low risk

  • CO2 453
  • CO 142
  • NH3 0
  • NO2 1
  • O3 75
  • PM10 9
  • PM25 6
  • SO2 0
  • CH4 1,387

Sunrise / Sunset

12:30
22:51