Climate and monthly weather forecastMount Vernon, IL
Climate and monthly weather forecast
Weather in January
January, like December, in Mount Vernon, Illinois, is another cold winter month, with an average temperature varying between 37.9°F (3.3°C) and 24.8°F (-4°C). With average high and low temperatures of 37.9°F (3.3°C) and 24.8°F (-4°C) respectively, January is Mount Vernon's coldest month. Weather in January »Weather in February
February, the last month of the winter in Mount Vernon, is also an icy month, with an average temperature ranging between min 28.8°F (-1.8°C) and max 42.4°F (5.8°C). The onset of February brings an average high-temperature of a still wintry 42.4°F (5.8°C), nearly matching the January temperature. Weather in February »Weather in March
The first month of the spring, March, is a cool month in Mount Vernon, Illinois, with an average temperature ranging between min 38.3°F (3.5°C) and max 54.3°F (12.4°C). As March arrives, Mount Vernon's weather shows an increase in high-temperatures, moving from February's icy 42.4°F (5.8°C) to a fresh 54.3°F (12.4°C). Weather in March »Weather in April
April is a refreshing spring month in Mount Vernon, Illinois, with an average temperature varying between 47.8°F (8.8°C) and 65.1°F (18.4°C). The onset of April brings a temperature shift, with the average high-temperature moving from a cool 54.3°F (12.4°C) in March to an enjoyable 65.1°F (18.4°C). Weather in April »Weather in May
May, the last month of the spring in Mount Vernon, is a warm month, with an average temperature fluctuating between 57.9°F (14.4°C) and 74.8°F (23.8°C). As April transitions into May, Mount Vernon sees a rise in the average high-temperature, moving from a refreshing 65.1°F (18.4°C) to a moderately hot 74.8°F (23.8°C). Weather in May »Weather in June
The first month of the summer, June, is also a moderately hot month in Mount Vernon, Illinois, with an average temperature fluctuating between 66.6°F (19.2°C) and 83.5°F (28.6°C). As Mount Vernon enters June, the average high-temperature marginally increases from the a warm 74.8°F (23.8°C) of May to a still moderately hot 83.5°F (28.6°C). Weather in June »Weather in July
July, like June, in Mount Vernon, Illinois, is a moderately hot summer month, with an average temperature ranging between max 85.6°F (29.8°C) and min 67.8°F (19.9°C). July, characterized by an average high temperature of 85.6°F (29.8°C) and a low temperature of 67.8°F (19.9°C), is generally the warmest month. July's heat index is evaluated at a fiery hot 98.6°F (37°C). Weather in July »Weather in August
August, the last month of the summer in Mount Vernon, is also a moderately hot month, with an average temperature fluctuating between 65.8°F (18.8°C) and 84°F (28.9°C). The commencement of August brings an average high-temperature of a still warm 84°F (28.9°C), marking an inconsequential divergence from July. Weather in August »Weather in September
September, the first month of the autumn in Mount Vernon, is still a warm month, with an average temperature fluctuating between 79°F (26.1°C) and 60.1°F (15.6°C). As Mount Vernon transitions into September, the average high-temperature stands at a still warm 79°F (26.1°C), offering little variation from the preceding month. Weather in September »Weather in October
October, the same as September, is another enjoyable autumn month in Mount Vernon, Illinois, with an average temperature ranging between max 66.4°F (19.1°C) and min 49.1°F (9.5°C). Start of October brings a shift in the average high-temperature, falling from September's warm 79°F (26.1°C) to a refreshing 66.4°F (19.1°C). Weather in October »Weather in November
The last month of the autumn, November, is also a fresh month in Mount Vernon, Illinois, with an average temperature fluctuating between 52.7°F (11.5°C) and 37.9°F (3.3°C). A shift in the average high-temperature occurs in November, reducing from an enjoyable 66.4°F (19.1°C) in October to a cool 52.7°F (11.5°C). Weather in November »Weather in December
December, the first month of the winter in Mount Vernon, is still a chilly month, with temperature in the range of an average high of 43.2°F (6.2°C) and an average low of 30.9°F (-0.6°C). The transition into December indicates a reduction in the average high-temperature, down to a chilly 43.2°F (6.2°C) from November's fresh 52.7°F (11.5°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
January, on average, is the coldest month in Mount Vernon, registering a high temperature of 37.9°F (3.3°C) and a low of 24.8°F (-4°C).
In Mount Vernon, during the entire year, the rain falls for 145.8 days and collects up to 29.13" (740mm) of precipitation.
Months with snowfall in Mount Vernon are January through April, November and December.
In Mount Vernon, during the entire year, snow falls for 15.4 days and aggregates up to 5.87" (149mm) of snow.
With an average of 4.5h of sunshine, January has the least sunshine of the year in Mount Vernon.
January, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Mount Vernon, Illinois.
The month with the most snowfall is February, when snow falls for 4.5 days and typically aggregates up to 1.73" (44mm) of snow.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Mount Vernon, 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 month with the most rainfall is April, when the rain falls for 14.7 days and typically aggregates up to 3.78" (96mm) of precipitation.
With an average relative humidity of 80%, May is the most humid month in Mount Vernon, Illinois.
In Mount Vernon, Illinois, snow does not fall in May through October.
The months with the highest UV index in Mount Vernon are May through August, with an average maximum UV index of 6.
With an average of 14h and 48min of daylight, June has the longest days of the year in Mount Vernon, Illinois.
With an average of 10.5h of sunshine, June has the most sunshine of the year in Mount Vernon, Illinois.
Mount Vernon experiences its average highest temperatures in July, reaching a peak of 85.6°F (29.8°C) and a minimum of 67.8°F (19.9°C).
September is the month with the least rainfall. Rain falls for 11.6 days and accumulates 1.61" (41mm) of precipitation.
With an average relative humidity of 71%, October is the least humid month in Mount Vernon.
December has the shortest days of the year in Mount Vernon, Illinois, with an average of 9h and 36min of daylight.
Average temperature
Mount Vernon, IL
The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is January (37.9°F).
The month with the highest average low temperature is July (67.8°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).
Average pressure
Mount Vernon, IL
- Average pressure in January:
30.16"Hg - Average pressure in February:
30.12"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
29.95"Hg - Average pressure in May:
29.97"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:
30.04"Hg - Average pressure in November:
30.14"Hg - Average pressure in December:
30.14"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed
Mount Vernon, IL
- Average wind speed in January:
9.9mph - Average wind speed in February:
9.8mph - Average wind speed in March:
9.8mph - Average wind speed in April:
9.6mph - Average wind speed in May:
8.1mph - Average wind speed in June:
7mph
- Average wind speed in July:
5.9mph - Average wind speed in August:
5.9mph - Average wind speed in September:
6.5mph - Average wind speed in October:
8.3mph - Average wind speed in November:
8.9mph - Average wind speed in December:
9.1mph
The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.9mph).
Average humidity
Mount Vernon, IL
The month with the highest relative humidity is May (80%).
The month with the lowest relative humidity is October (71%).
Average rainfall
Mount Vernon, IL
- Average rainfall in January:
1.77" - Average rainfall in February:
1.77" - Average rainfall in March:
2.6" - Average rainfall in April:
3.78" - Average rainfall in May:
3.23" - Average rainfall in June:
3.11"
- Average rainfall in July:
2.76" - Average rainfall in August:
2.36" - Average rainfall in September:
1.61" - Average rainfall in October:
2.09" - Average rainfall in November:
2.05" - Average rainfall in December:
2.01"
The wettest month (with the highest rainfall) is April (3.78").
The driest month (with the least rainfall) is September (1.61").
Average rainfall days
Mount Vernon, IL
- Average rainfall days in January:
7.5 days - Average rainfall days in February:
8.8 days - Average rainfall days in March:
14.1 days - Average rainfall days in April:
14.7 days - Average rainfall days in May:
17 days - Average rainfall days in June:
14.9 days
- Average rainfall days in July:
15.9 days - Average rainfall days in August:
13.4 days - Average rainfall days in September:
11.6 days - Average rainfall days in October:
9.5 days - Average rainfall days in November:
9.5 days - Average rainfall days in December:
8.9 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is January (7.5 days).
Average snowfall
Mount Vernon, IL
The month with the highest snowfall is February (1.73").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days
Mount Vernon, IL
- Average snowfall days in January:
4.8 days - Average snowfall days in February:
4.5 days - Average snowfall days in March:
1.8 days - Average snowfall days in April:
0.3 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 days - Average snowfall days in November:
1.1 days - Average snowfall days in December:
2.9 days
The month with the highest number of snowfall days is January (4.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight / Average sunshine
Mount Vernon, IL
- Average daylight in January:
9h and 54min - Average daylight in February:
10h and 48min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 12min - Average daylight in May:
14h and 18min - Average daylight in June:
14h and 48min
- Average daylight in July:
14h and 30min - Average daylight in August:
13h and 36min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 12min - Average daylight in November:
10h and 6min - Average daylight in December:
9h and 36min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in January:
4h and 30min - Average sunshine in February:
4h and 42min - Average sunshine in March:
6h and 30min - Average sunshine in April:
8h and 30min - Average sunshine in May:
9h and 12min - Average sunshine in June:
10h and 30min
- Average sunshine in July:
10h and 24min - Average sunshine in August:
10h and 12min - Average sunshine in September:
9h and 18min - Average sunshine in October:
6h and 30min - Average sunshine in November:
5h and 36min - Average sunshine in December:
4h and 48min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).
Average sunshine days
Mount Vernon, IL
- Average sunshine days in January:
19.3 days - Average sunshine days in February:
15.4 days - Average sunshine days in March:
14.8 days - Average sunshine days in April:
13.7 days - Average sunshine days in May:
11.3 days - Average sunshine days in June:
12.8 days
- Average sunshine days in July:
13.3 days - Average sunshine days in August:
15.6 days - Average sunshine days in September:
16.4 days - Average sunshine days in October:
20.3 days - Average sunshine days in November:
18.7 days - Average sunshine days in December:
19.9 days
The month with the most sunshine days is October (20.3 days).
The month with the least sunshine days is May (11.3 days).
Average UV index
Mount Vernon, IL
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, November and December (UV index 2).
Average cloud cover
Mount Vernon, IL
The month with the most cloud cover is January (Cloud cover 51).
The month with the least cloud cover is June (Cloud cover 27).
Average visibility
Mount Vernon, 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).
