Climate and monthly weather forecastNorthbrook, IL
Climate and monthly weather forecast
Weather in January
January, the same as December, in Northbrook, Illinois, is a freezing cold winter month, with an average temperature fluctuating between 28.8°F (-1.8°C) and 18.9°F (-7.3°C). January is Northbrook's coldest month, registering average high temperatures of 28.8°F (-1.8°C) and lows of 18.9°F (-7.3°C). Weather in January »Weather in February
February, the last month of the winter in Northbrook, is also a subzero cold month, with an average temperature varying between 21.6°F (-5.8°C) and 31.8°F (-0.1°C). An average high-temperature of a still subzero cold 31.8°F (-0.1°C) marks February, exhibiting a close resemblance to the conditions in January. Weather in February »Weather in March
March, the first month of the spring in Northbrook, is an icy month, with an average temperature fluctuating between 42.3°F (5.7°C) and 31.5°F (-0.3°C). March's onset witnesses a shift in the average high-temperature, moving from a freezing cold 31.8°F (-0.1°C) in February to a wintry 42.3°F (5.7°C). Weather in March »Weather in April
April in Northbrook, Illinois, is a fresh spring month, with an average temperature ranging between min 39.7°F (4.3°C) and max 52°F (11.1°C). In Northbrook, the onset of April comes with an increased average high-temperature, moving from March's wintry 42.3°F (5.7°C) to a cool 52°F (11.1°C). Weather in April »Weather in May
The last month of the spring, May, is a comfortable month in Northbrook, Illinois, with an average temperature varying between 62.8°F (17.1°C) and 50.4°F (10.2°C). The onset of May marks an increase in the average high-temperature, moving from a fresh 52°F (11.1°C) in April to a comfortable 62.8°F (17.1°C). Weather in May »Weather in June
June, the first month of the summer in Northbrook, is an agreeable month, with an average temperature varying between 60.1°F (15.6°C) and 72.5°F (22.5°C). As Northbrook welcomes June, the average high-temperature sees a rise, transitioning from a comfortable 62.8°F (17.1°C) in May to a pleasant 72.5°F (22.5°C). Weather in June »Weather in July
July in Northbrook, Illinois, is a moderately hot summer month, with temperature in the range of an average high of 79.2°F (26.2°C) and an average low of 67.1°F (19.5°C). The warmest month is July, with an average high-temperature of 79.2°F (26.2°C) and an average low-temperature of 67.1°F (19.5°C). Weather in July »Weather in August
The last month of the summer, August, is also a moderately hot month in Northbrook, Illinois, with an average temperature fluctuating between 66.9°F (19.4°C) and 78.1°F (25.6°C). Northbrook transitions into August recording an average high-temperature of a still moderately hot 78.1°F (25.6°C), closely aligning with the preceding month's temperature. Weather in August »Weather in September
The first month of the autumn, September, is also an agreeable month in Northbrook, Illinois, with an average temperature fluctuating between 60.3°F (15.7°C) and 71.6°F (22°C). September brings a minor shift in the average high-temperature, adjusting from a warm 78.1°F (25.6°C) in August to an agreeable 71.6°F (22°C). Weather in September »Weather in October
October, the same as September, in Northbrook, Illinois, is another mild autumn month, with an average temperature ranging between max 59.5°F (15.3°C) and min 47.7°F (8.7°C). Northbrook's transition into October involves a shift in temperature, receding from a pleasant 71.6°F (22°C) in September to a moderate 59.5°F (15.3°C). Weather in October »Weather in November
The last month of the autumn, November, is also a frosty month in Northbrook, Illinois, with an average temperature fluctuating between 45.5°F (7.5°C) and 35.1°F (1.7°C). With the beginning of November, the average high-temperature shows a decrease, transitioning from a moderate 59.5°F (15.3°C) in October to a frosty 45.5°F (7.5°C). Weather in November »Weather in December
December, the first month of the winter in Northbrook, is also a wintry month, with an average temperature varying between 26.1°F (-3.3°C) and 34.9°F (1.6°C). The shift to December brings a decrease in the average high-temperature, falling from a chilly 45.5°F (7.5°C) in November to a cold 34.9°F (1.6°C). Weather in December »Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature
Northbrook, IL
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (28.8°F).
The month with the highest average low temperature is July (67.1°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure
Northbrook, IL
- Average pressure in January:
30.11"Hg - Average pressure in February:
30.09"Hg - Average pressure in March:
30.09"Hg - Average pressure in April:
29.95"Hg - Average pressure in May:
29.96"Hg - Average pressure in June:
29.92"Hg
- Average pressure in July:
29.97"Hg - Average pressure in August:
29.98"Hg - Average pressure in September:
30.03"Hg - Average pressure in October:
30"Hg - Average pressure in November:
30.09"Hg - Average pressure in December:
30.09"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Northbrook, IL
- Average wind speed in January:
11.5mph - Average wind speed in February:
11.1mph - Average wind speed in March:
10.4mph - Average wind speed in April:
10.6mph - Average wind speed in May:
8.9mph - Average wind speed in June:
8mph
- Average wind speed in July:
7.3mph - Average wind speed in August:
7.1mph - Average wind speed in September:
8.6mph - Average wind speed in October:
10.3mph - Average wind speed in November:
11mph - Average wind speed in December:
10.7mph
The windiest month (with the highest average wind speed) is January (11.5mph).
The calmest month (with the lowest average wind speed) is August (7.1mph).
Average humidity
Northbrook, IL
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall
Northbrook, IL
- Average rainfall in January:
1.77" - Average rainfall in February:
1.85" - Average rainfall in March:
2.01" - Average rainfall in April:
3.78" - Average rainfall in May:
4.57" - Average rainfall in June:
4.57"
The wettest months (with the highest rainfall) are May and June (4.57").
The driest month (with the least rainfall) is December (1.65").
Average rainfall days
Northbrook, IL
- Average rainfall days in January:
7.3 days - Average rainfall days in February:
6.1 days - Average rainfall days in March:
12.2 days - Average rainfall days in April:
16.5 days - Average rainfall days in May:
19.1 days - Average rainfall days in June:
18.2 days
- Average rainfall days in July:
18.4 days - Average rainfall days in August:
17.7 days - Average rainfall days in September:
14.8 days - Average rainfall days in October:
14.5 days - Average rainfall days in November:
10.8 days - Average rainfall days in December:
9.1 days
The month with the highest number of rainy days is May (19.1 days).
The month with the least rainy days is February (6.1 days).
Average snowfall
Northbrook, IL
- Average snowfall in January:
4.84" - Average snowfall in February:
4.65" - Average snowfall in March:
1.22" - Average snowfall in April:
2.44" - Average snowfall in May:
0.08" - Average snowfall in June:
0"
The month with the highest snowfall is January (4.84").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Northbrook, IL
- Average snowfall days in January:
13.1 days - Average snowfall days in February:
11.2 days - Average snowfall days in March:
6.7 days - Average snowfall days in April:
2.3 days - Average snowfall days in May:
0.1 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0.3 days - Average snowfall days in November:
3.9 days - Average snowfall days in December:
10 days
The month with the highest number of snowfall days is January (13.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Northbrook, IL
- Average daylight in January:
9h and 30min - Average daylight in February:
10h and 36min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 24min - Average daylight in May:
14h and 36min - Average daylight in June:
15h and 12min
- Average daylight in July:
14h and 54min - Average daylight in August:
13h and 48min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 6min - Average daylight in November:
9h and 48min - Average daylight in December:
9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in January:
3h and 42min - Average sunshine in February:
3h and 54min - Average sunshine in March:
6h and 6min - Average sunshine in April:
7h and 48min - Average sunshine in May:
8h and 42min - Average sunshine in June:
9h and 48min
- Average sunshine in July:
10h and 24min - Average sunshine in August:
10h and 24min - Average sunshine in September:
9h and 0min - Average sunshine in October:
5h and 42min - Average sunshine in November:
5h and 6min - Average sunshine in December:
4h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days
Northbrook, IL
- Average sunshine days in January:
11.8 days - Average sunshine days in February:
10.9 days - Average sunshine days in March:
13.3 days - Average sunshine days in April:
10.2 days - Average sunshine days in May:
10 days - Average sunshine days in June:
9.2 days
- Average sunshine days in July:
9.3 days - Average sunshine days in August:
10.5 days - Average sunshine days in September:
11.7 days - Average sunshine days in October:
13.4 days - Average sunshine days in November:
15.5 days - Average sunshine days in December:
14.3 days
The month with the most sunshine days is November (15.5 days).
The month with the least sunshine days is June (9.2 days).
Average UV index
Northbrook, IL
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover
Northbrook, IL
The month with the most cloud cover is January (Cloud cover 61).
The months with the least cloud cover are July and August (Cloud cover 28).
Average visibility
Northbrook, IL
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).





