Climate and monthly weather forecastLake Forest, IL
Climate and monthly weather forecast
Weather in January
January, the same as December, in Lake Forest, Illinois, is another subzero cold winter month, with temperature in the range of an average low of 18.9°F (-7.3°C) and an average high of 28.6°F (-1.9°C). With average high temperatures of 28.6°F (-1.9°C) and lows of 18.9°F (-7.3°C), January is the coldest month. Weather in January »Weather in February
The last month of the winter, February, is also a subzero cold month in Lake Forest, Illinois, with an average temperature fluctuating between 31.3°F (-0.4°C) and 21.6°F (-5.8°C). The average high-temperature during February registers at a still freezing cold 31.3°F (-0.4°C), maintaining a close resemblance to the previous month. Weather in February »Weather in March
March, the first month of the spring in Lake Forest, is a cold month, with an average temperature varying between 31.5°F (-0.3°C) and 41.5°F (5.3°C). With the onset of March, Lake Forest experiences a temperature shift, with the average high-temperature moving from a freezing cold 31.3°F (-0.4°C) in February to an icy 41.5°F (5.3°C). Weather in March »Weather in April
April is a cool spring month in Lake Forest, Illinois, with an average temperature varying between 50.9°F (10.5°C) and 39.7°F (4.3°C). As Lake Forest transitions into April, the average high-temperature shows a change, moving from an icy 41.5°F (5.3°C) in March to a fresh 50.9°F (10.5°C). Weather in April »Weather in May
The last month of the spring, May, is a comfortable month in Lake Forest, Illinois, with an average temperature varying between 49.6°F (9.8°C) and 61.2°F (16.2°C). May sees a rise in the average high-temperature, climbing from a cool 50.9°F (10.5°C) in April to a comfortable 61.2°F (16.2°C). Weather in May »Weather in June
June, the first month of the summer in Lake Forest, is an agreeable month, with an average temperature fluctuating between 59.4°F (15.2°C) and 71.1°F (21.7°C). June's onset witnesses a shift in the average high-temperature, moving from a refreshing 61.2°F (16.2°C) in May to a pleasant 71.1°F (21.7°C). Weather in June »Weather in July
July in Lake Forest, Illinois, is a moderately hot summer month, with an average temperature fluctuating between 66.7°F (19.3°C) and 77.7°F (25.4°C). Lake Forest, Illinois, experiences its highest average temperatures in July, reaching a peak of 77.7°F (25.4°C) and a minimum of 66.7°F (19.3°C). Weather in July »Weather in August
August, the last month of the summer in Lake Forest, is also a moderately hot month, with an average temperature ranging between max 77.5°F (25.3°C) and min 66.7°F (19.3°C). The arrival of August is marked by an average high-temperature of a still warm 77.5°F (25.3°C), bearing a close resemblance to July. Weather in August »Weather in September
September, the first month of the autumn in Lake Forest, is also an agreeable month, with temperature in the range of an average high of 71.2°F (21.8°C) and an average low of 60.1°F (15.6°C). With the onset of September, Lake Forest's climate undergoes a slight change as the average high-temperature moves from a warm 77.5°F (25.3°C) in August to an agreeable 71.2°F (21.8°C). Weather in September »Weather in October
October, like September, is a moderate autumn month in Lake Forest, Illinois, with an average temperature fluctuating between 47.7°F (8.7°C) and 58.6°F (14.8°C). The shift from September to October corresponds with a decrease in the average high-temperature, down to a mild 58.6°F (14.8°C) from an agreeable 71.2°F (21.8°C). Weather in October »Weather in November
November, the last month of the autumn in Lake Forest, is another chilly month, with temperature in the range of an average high of 45.5°F (7.5°C) and an average low of 35.1°F (1.7°C). Lake Forest experiences a temperature shift at the start of November, with average high-temperatures adjusting from a refreshing 58.6°F (14.8°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 Lake Forest, is still a cold month, with an average temperature varying between 26.2°F (-3.2°C) and 34.5°F (1.4°C). Lake Forest in December experiences a subtle temperature decline, with average high-temperatures reducing from a chilly 45.5°F (7.5°C) in November to a cold 34.5°F (1.4°C). Weather in December »Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Lake Forest's January weather, with an average high temperature of 28.6°F (-1.9°C) and an average low temperature of 18.9°F (-7.3°C), tends to be the coldest of the year.
January and February, with an average relative humidity of 82%, are most humid months.
In Lake Forest, during the entire year, the rain falls for 154.1 days and collects up to 30.24" (768mm) of precipitation.
January through April, October through December are months with snowfall in Lake Forest, Illinois.
January is the month with the most snowfall in Lake Forest, Illinois. Snow falls for 11.9 days and accumulates 4.13" (105mm) of snow.
Throughout the year, in Lake Forest, Illinois, there are 42.9 snowfall days, and 13.82" (351mm) of snow is accumulated.
January has the least sunshine of the year in Lake Forest, with an average of 3.8h of sunshine.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Lake Forest, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.
The wettest months in Lake Forest, Illinois, are May and June, with an average 3.82" (97mm) of rainfall.
May through September are months without snowfall in Lake Forest.
With an average of 15h and 12min of daylight, June has the longest days of the year in Lake Forest, Illinois.
June through August, with an average maximum UV index of 6, are months with the highest UV index in Lake Forest.
In Lake Forest, July registers the highest temperatures, averaging 77.7°F (25.4°C) at the peak and 66.7°F (19.3°C) at the lowest.
The month with the most sunshine is August, with an average of 10.7h of sunshine.
The least humid month in Lake Forest, Illinois, is October, with an average relative humidity of 73%.
December is the month with the least rainfall. Rain falls for 8.6 days and accumulates 1.3" (33mm) of precipitation.
With an average of 9h and 12min of daylight, December has the shortest days of the year.
With an average maximum UV index of 1, December is the month with the lowest UV index.
Average temperature
Lake Forest, IL
The warmest month (with the highest average high temperature) is July (77.7°F).
The month with the lowest average high temperature is January (28.6°F).
The months with the highest average low temperature are July and August (66.7°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure
Lake Forest, IL
- Average pressure in January:
30.1"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 (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed
Lake Forest, IL
- Average wind speed in January:
11.9mph - Average wind speed in February:
11.6mph - Average wind speed in March:
10.7mph - Average wind speed in April:
10.8mph - Average wind speed in May:
9.1mph - Average wind speed in June:
8.1mph
- Average wind speed in July:
7.5mph - Average wind speed in August:
7.4mph - Average wind speed in September:
8.9mph - Average wind speed in October:
10.7mph - Average wind speed in November:
11.5mph - Average wind speed in December:
11.2mph
The windiest month (with the highest average wind speed) is January (11.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).
Average humidity
Lake Forest, IL
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall
Lake Forest, IL
- Average rainfall in January:
1.54" - Average rainfall in February:
1.54" - Average rainfall in March:
1.77" - Average rainfall in April:
3.43" - Average rainfall in May:
3.82" - Average rainfall in June:
3.82"
The wettest months (with the highest rainfall) are May and June (3.82").
The driest month (with the least rainfall) is December (1.3").
Average rainfall days
Lake Forest, IL
- Average rainfall days in January:
6.2 days - Average rainfall days in February:
5.9 days - Average rainfall days in March:
11.3 days - Average rainfall days in April:
16.1 days - Average rainfall days in May:
17.7 days - Average rainfall days in June:
16.6 days
- Average rainfall days in July:
17.4 days - Average rainfall days in August:
15.8 days - Average rainfall days in September:
13.6 days - Average rainfall days in October:
14.7 days - Average rainfall days in November:
10.2 days - Average rainfall days in December:
8.6 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (5.9 days).
Average snowfall
Lake Forest, IL
The month with the highest snowfall is January (4.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days
Lake Forest, IL
- Average snowfall days in January:
11.9 days - Average snowfall days in February:
9.5 days - Average snowfall days in March:
5.8 days - Average snowfall days in April:
2.4 days - Average snowfall days in May:
0 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:
0.5 days - Average snowfall days in November:
3.7 days - Average snowfall days in December:
9.1 days
The month with the highest number of snowfall days is January (11.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Lake Forest, 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 48min - Average sunshine in February:
3h and 54min - Average sunshine in March:
6h and 12min - Average sunshine in April:
7h and 54min - Average sunshine in May:
8h and 54min - Average sunshine in June:
10h and 0min
- Average sunshine in July:
10h and 36min - Average sunshine in August:
10h and 42min - Average sunshine in September:
9h and 12min - Average sunshine in October:
5h and 42min - Average sunshine in November:
5h and 6min - Average sunshine in December:
4h and 6min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days
Lake Forest, IL
- Average sunshine days in January:
12.8 days - Average sunshine days in February:
12.3 days - Average sunshine days in March:
14 days - Average sunshine days in April:
10.8 days - Average sunshine days in May:
11.2 days - Average sunshine days in June:
11.2 days
- Average sunshine days in July:
11.5 days - Average sunshine days in August:
13.1 days - Average sunshine days in September:
13.3 days - Average sunshine days in October:
13.6 days - Average sunshine days in November:
14.7 days - Average sunshine days in December:
15.3 days
The month with the most sunshine days is December (15.3 days).
The month with the least sunshine days is April (10.8 days).
Average UV index
Lake Forest, 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
Lake Forest, 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 27).
Average visibility
Lake Forest, 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).
