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Contents
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average snowfall
- Average snowfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
Weather in January
January, the same as December, is an icy winter month in Janesville, Illinois, with temperature in the range of an average high of 34°F (1.1°C) and an average low of 21.9°F (-5.6°C). January, with an average high of 34°F (1.1°C) and a low of 21.9°F (-5.6°C), signifies the coldest month of the year. Weather in January »
Weather in February
The last month of the winter, February, is another cold month in Janesville, Illinois, with an average temperature ranging between min 26.1°F (-3.3°C) and max 39°F (3.9°C). The average high-temperature during February registers at a still cold 39°F (3.9°C), maintaining a close resemblance to the previous month. Weather in February »
Weather in March
March, the first month of the spring in Janesville, is a cool month, with an average temperature ranging between min 36.1°F (2.3°C) and max 51.1°F (10.6°C). The transition from February to March brings a temperature rise, with average high-temperatures increasing from an icy 39°F (3.9°C) to a fresh 51.1°F (10.6°C). Weather in March »
Weather in April
April is an enjoyable spring month in Janesville, Illinois, with temperature in the range of an average high of 62.2°F (16.8°C) and an average low of 46.2°F (7.9°C). With the onset of April, Janesville's average high-temperature sees a rise, moving from March's cool 51.1°F (10.6°C) to a refreshing 62.2°F (16.8°C). Weather in April »
Weather in May
May, the last month of the spring in Janesville, is an agreeable month, with an average temperature ranging between max 73°F (22.8°C) and min 56.7°F (13.7°C). May's onset brings a temperature rise, moving from a comfortable 62.2°F (16.8°C) in April to a pleasant 73°F (22.8°C). Weather in May »
Weather in June
The first month of the summer, June, is a moderately hot month in Janesville, Illinois, with an average temperature ranging between min 64.2°F (17.9°C) and max 81.1°F (27.3°C). The onset of June brings a minor temperature shift, with the average high-temperature moving from an agreeable 73°F (22.8°C) in May to a warm 81.1°F (27.3°C). Weather in June »
Weather in July
July, like June, in Janesville, Illinois, is another warm summer month, with temperature in the range of an average low of 65.8°F (18.8°C) and an average high of 82°F (27.8°C). July registers as the month with the highest average temperatures, reaching 82°F (27.8°C) at its peak and 65.8°F (18.8°C) at the lowest. For July, the heat index is evaluated at a hot 89.6°F (32°C). Weather in July »
Weather in August
August, the last month of the summer in Janesville, is also a moderately hot month, with an average temperature ranging between min 64°F (17.8°C) and max 81.1°F (27.3°C). August's presence marks an average high-temperature of a still warm 81.1°F (27.3°C), subtly varied from July's 82°F (27.8°C). Weather in August »
Weather in September
The first month of the autumn, September, is still a warm month in Janesville, Illinois, with an average temperature varying between 58.5°F (14.7°C) and 77.2°F (25.1°C). September ushers in an average high-temperature of a still warm 77.2°F (25.1°C), aligning closely with the preceding month. Weather in September »
Weather in October
October, like September, in Janesville, Illinois, is another enjoyable autumn month, with an average temperature varying between 48.2°F (9°C) and 63.9°F (17.7°C). Janesville experiences a temperature shift at the start of October, with average high-temperatures adjusting from a warm 77.2°F (25.1°C) in September to a comfortable 63.9°F (17.7°C). Weather in October »
Weather in November
The last month of the autumn, November, is another chilly month in Janesville, Illinois, with temperature in the range of an average low of 36.1°F (2.3°C) and an average high of 49.8°F (9.9°C). The onset of November coincides with a reduction in the average high-temperature, falling from an enjoyable 63.9°F (17.7°C) in October to a chilly 49.8°F (9.9°C). Weather in November »
Weather in December
The first month of the winter, December, is also an icy month in Janesville, Illinois, with an average temperature fluctuating between 28.8°F (-1.8°C) and 39°F (3.9°C). Onset of December comes with a temperature decline, the average high falling from a frosty 49.8°F (9.9°C) in November to an icy 39°F (3.9°C). Weather in December »
Updated: Jul 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
What is the coldest time of year?
January is the coldest month, with an average high-temperature of 34°F (1.1°C) and an average low-temperature of 21.9°F (-5.6°C).
How many days does it rain?
Throughout the year, there are 148 rainfall days, and 25.63" (651mm) of precipitation is accumulated.
When does it snow?
January through April, October through December are months with snowfall.
How many days does it snow in Janesville?
Throughout the year, there are 26.6 snowfall days, and 7.01" (178mm) of snow is accumulated.
What is the month with the least sunshine?
January has the least sunshine of the year, with an average of 4h of sunshine.
What is the driest month?
February is the month with the least rainfall. Rain falls for 7.8 days and accumulates 1.3" (33mm) of precipitation.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, 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.
What is the rainiest month?
The month with the most rainfall is April, when the rain falls for 14.9 days and typically aggregates up to 3.31" (84mm) of precipitation.
When it does not snow?
In Janesville, snow does not fall in May through September.
When are the longest days?
June has the longest days of the year, with an average of 14h and 54min of daylight.
What month has the most sunshine?
The month with the most sunshine is June, with an average of 10.3h of sunshine.
What are the months with the highest UV index?
The months with the highest UV index are June through August, with an average maximum UV index of 6.
What month is the hottest?
July is the warmest month, with the temperature often reaching an average high of 82°F (27.8°C) and an average low of 65.8°F (18.8°C).
What is the most humid month?
With an average relative humidity of 83%, July is the most humid month in Janesville.
What is the least humid month?
October is the least humid month, with an average relative humidity of 70%.
What is the snowiest month?
December is the month with the most snowfall in Janesville, Illinois. Snow falls for 6 days and accumulates 2.13" (54mm) of snow.
What is the month with the shortest days in Janesville?
With an average of 9h and 24min of daylight, December has the shortest days of the year.
When is the lowest UV index?
December is the month with the lowest UV index, with an average maximum UV index of 1.
Average temperature
Janesville, IL
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (34°F).
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (21.9°F).
Average pressure
Janesville, IL
- Average pressure in January:
30.15"Hg - Average pressure in February:
30.11"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
29.95"Hg - Average pressure in May:
29.96"Hg - Average pressure in June:
29.93"Hg
- Average pressure in July:
29.98"Hg - Average pressure in August:
29.98"Hg - Average pressure in September:
30.03"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.13"Hg - Average pressure in December:
30.13"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed
Janesville, IL
- Average wind speed in January:
10.7mph - Average wind speed in February:
10.6mph - Average wind speed in March:
10.3mph - Average wind speed in April:
10.4mph - Average wind speed in May:
8.6mph - Average wind speed in June:
7.4mph
- Average wind speed in July:
6.2mph - Average wind speed in August:
6.3mph - Average wind speed in September:
7.1mph - Average wind speed in October:
9.2mph - Average wind speed in November:
9.9mph - Average wind speed in December:
9.9mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is July (6.2mph).
Average humidity
Janesville, IL
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall
Janesville, IL
- Average rainfall in January:
1.81" - Average rainfall in February:
1.3" - Average rainfall in March:
2.09" - Average rainfall in April:
3.31" - Average rainfall in May:
2.87" - Average rainfall in June:
2.76"
- Average rainfall in July:
2.52" - Average rainfall in August:
2.28" - Average rainfall in September:
1.38" - Average rainfall in October:
2.13" - Average rainfall in November:
1.61" - Average rainfall in December:
1.57"
The wettest month (with the highest rainfall) is April (3.31").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days
Janesville, IL
- Average rainfall days in January:
8.2 days - Average rainfall days in February:
7.8 days - Average rainfall days in March:
12.5 days - Average rainfall days in April:
14.9 days - Average rainfall days in May:
16.8 days - Average rainfall days in June:
15.6 days
- Average rainfall days in July:
16.6 days - Average rainfall days in August:
14.3 days - Average rainfall days in September:
12.1 days - Average rainfall days in October:
11.1 days - Average rainfall days in November:
8.7 days - Average rainfall days in December:
9.4 days
The month with the highest number of rainy days is May (16.8 days).
The month with the least rainy days is February (7.8 days).
Average snowfall
Janesville, IL
The month with the highest snowfall is December (2.13").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days
Janesville, IL
- Average snowfall days in January:
8.1 days - Average snowfall days in February:
6.8 days - Average snowfall days in March:
3.2 days - Average snowfall days in April:
0.7 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:
0.1 days - Average snowfall days in November:
1.7 days - Average snowfall days in December:
6 days
The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight / Average sunshine
Janesville, IL
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 4min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 2min - Average daylight in May:
14h and 2min - Average daylight in June:
14h and 5min
- Average daylight in July:
14h and 4min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 0min - Average daylight in December:
9h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in January:
4h and 0min - Average sunshine in February:
4h and 1min - Average sunshine in March:
6h and 1min - Average sunshine in April:
8h and 0min - Average sunshine in May:
8h and 5min - Average sunshine in June:
10h and 2min
- Average sunshine in July:
9h and 5min - Average sunshine in August:
9h and 5min - Average sunshine in September:
8h and 5min - Average sunshine in October:
6h and 2min - Average sunshine in November:
5h and 1min - Average sunshine in December:
4h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days
Janesville, IL
- Average sunshine days in January:
15.9 days - Average sunshine days in February:
14 days - Average sunshine days in March:
15.2 days - Average sunshine days in April:
12.9 days - Average sunshine days in May:
11.2 days - Average sunshine days in June:
11.5 days
- Average sunshine days in July:
10.6 days - Average sunshine days in August:
12.7 days - Average sunshine days in September:
15.7 days - Average sunshine days in October:
18.3 days - Average sunshine days in November:
17.9 days - Average sunshine days in December:
16.9 days
The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is July (10.6 days).
Average UV index
Janesville, 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
Janesville, IL
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is June (Cloud cover 31).
Average visibility
Janesville, IL
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Janesville, Illinois, USA
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