Mount Vernon (IL) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Mount Vernon.
Climate overview of Mount Vernon
The climate in Mount Vernon, Illinois, United States of America, is marked by large temperature swings across the seasons, ranging from 31°C (88°F) in July to 4°C (39°F) in January.
The city has a wet climate, receiving around 1215 mm (48 in) of rain/snowfall per year. Despite the high annual total, it has very warm summers and cold winters. April is the wettest month.
Mount Vernon Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Mount Vernon - and find the best time to visit.
Monthly Temperature in Mount Vernon
In Mount Vernon, temperatures differ significantly between summer and winter months. On average, daytime temperatures range from a very warm 31°C (88°F) in July to a chilly 4°C (39°F) in January.
Nighttime temperatures range from 20°C (68°F) in July to -6°C (21°F) in January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Mount Vernon
Mount Vernon experiences significant rain/snowfall throughout the year, averaging 1215 mm (48 in) of precipitation annually. The seasons in Mount Vernon bring significant changes in precipitation. The wettest month, April, receives high rainfall, with an average of 134 mm (5.3 in) of precipitation. This rainfall is distributed across 11 rainy days.
In contrast, the driest month, January, experiences much less snow/rainfall, totaling 59 mm (2.3 in) over 8 snowy/rainy days. These distinct seasonal differences provide diverse experiences throughout the year. For more details, please visit our Mount Vernon Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Best Time to Visit Mount Vernon
Each month is rated for comfortable sightseeing weather — mild temperatures and low rainfall. Tap a month for its full averages; your ideal time may differ for a beach or winter trip (see below).
- Best overall: September and October
- Warmest weather: June, July and August
- Climate seasons: very warm summers and cold winters
- Best for winter weather: January, with freezing nights around -6°C (21°F).
Frequently asked questions about the climate in Mount Vernon
What is the best time to visit Mount Vernon?
September and October typically offer the most optimal weather in Mount Vernon. In contrast, January, February, March and December tend to have less optimal conditions. Mount Vernon has very warm summers and cold winters.
What temperatures can I expect in Mount Vernon?
Daytime highs range from 4°C (39°F) in January to 31°C (88°F) in July. Nighttime lows range from -6°C (21°F) to 20°C (68°F). Temperatures vary considerably through the year.
How much rain does Mount Vernon get?
Annual rainfall is around 1215 mm (48 in). April is the wettest month with 134 mm (5.3 in), while January is the driest with 59 mm (2.3 in).
Mount Vernon 3-Day Forecast
Mount Vernon (IL) 3-Day Forecast
Mount Vernon on the map
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