Climate guideThirty-year normals for Normal, Illinois
Normal climate by month
Hot-summer humid continental · DfaBest Apr · Sep–Oct
Annual mean51°day and night
Seasonal swing50°warmest vs coolest
Precipitation40.6 in122 wet days a year
40.51° N, 88.99° WElevation 801 ftUTC−5 · Central Daylight Time
When to goNormal · weather score
Best timeApr · Sep–Oct
October: high / low65° / 42°
iSummary
What the weather is like
Normal has a hot-summer humid continental climate (Köppen Dfa): warm summers, cold winters and precipitation in every season.
The warmest month is July, when afternoons average 85° and nights 64°. January is the coolest month, with highs of 33° and lows of 16°. The difference between the warmest and the coolest month is about 50°, a large swing typical of continental interiors.
About 40.6 in of precipitation falls in an average year. May is the wettest month (4.7 in, 14 wet days) and January the driest (2.2 in, 8 wet days). Cloud cover ranges from 28% in August to 49% in December.
Compared with Washington, the capital, Normal is 2.2° cooler on a July afternoon and receives less precipitation over the year.
Year in figures
- Hottest afternoons
- 85° · July
- Coldest nights
- 16° · January
- Wettest month
- May
- Driest month
- January
- Clearest skies
- August · 28% cloud
- Longest day
- 15 h 03 min
- Shortest day
- 9 h 18 min
iiCharts
Twelve months at a glance
Temperature and precipitation
Daily high/low range bars, monthly precipitation columnsTemperature curve
Average high, lowDaylight
Hours between sunrise and sunset on the 15th of each monthiiiData table
Climate normals month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Average high | 33° | 38° | 50° | 63° | 73° | 82° | 85° | 84° | 78° | 65° | 50° | 37° |
| Average low | 16° | 19° | 29° | 39° | 51° | 60° | 64° | 62° | 54° | 42° | 31° | 22° |
| Precipitation | 2.2 in | 2.0 in | 2.8 in | 4.0 in | 4.7 in | 4.3 in | 4.5 in | 3.9 in | 3.1 in | 3.2 in | 3.3 in | 2.7 in |
| Wet days (≥1 mm) | 7.5 | 7.5 | 9.9 | 11 | 14.2 | 13 | 13.3 | 11.6 | 9.4 | 9.2 | 8 | 7.8 |
| Cloud cover | 47% | 47% | 44% | 42% | 40% | 35% | 30% | 28% | 30% | 37% | 44% | 49% |
| Daylight | 9h 36 | 10h 41 | 11h 54 | 13h 17 | 14h 26 | 15h 03 | 14h 47 | 13h 48 | 12h 29 | 11h 10 | 9h 57 | 9h 18 |
| Month score | 33 | 33 | 29 | 64 | 63 | 55 | 50 | 57 | 76 | 75 | 33 | 32 |
ivMonth by month
Normal in every month
January33
33° / 16°
2.2 in · 7.5 wet days
February33
38° / 19°
2.0 in · 7.5 wet days
March29
50° / 29°
2.8 in · 9.9 wet days
April64
63° / 39°
4.0 in · 11 wet days
May63
73° / 51°
4.7 in · 14.2 wet days
June55
82° / 60°
4.3 in · 13 wet days
July50
85° / 64°
4.5 in · 13.3 wet days
August57
84° / 62°
3.9 in · 11.6 wet days
September76
78° / 54°
3.1 in · 9.4 wet days
October75
65° / 42°
3.2 in · 9.2 wet days
November33
50° / 31°
3.3 in · 8 wet days
December32
37° / 22°
2.7 in · 7.8 wet days