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
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: September and October
- Warmest weather: June, July and August
- Seasonal pattern: Very warm summers and cold winters
- Coldest conditions: 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 on the map
Mount Vernon is highlighted - select any city to see its climate.
Popular this month
Where to go in August - average daytime high across popular destinations.
Kissimmee
33°C (91°F) Orlando33°C (91°F) Miami Beach32°C (90°F) Destin32°C (90°F) New York City
29°C (84°F) Big Bear Lake
27°C (81°F) Los Angeles
24°C (75°F) San Francisco22°C (72°F) 
Bucket list
Need travel inspiration? Check out our bucket list articles and be inspired.
Yosemite National Park is definitely worth a visit
Vast forests, blue lakes, towering sequoias, and majestic waterfalls hint at the beauty of Yosemite National Park—a true natural masterpiece.
The 10 most alternative cities in the United States
Discover the top 10 fun and alternative U.S. cities rich in art, culture, and adventure. From Portland's hippy charm to Sedona's stunning landscapes.
Sedona: Explore Majestic Red Rock Landscapes
A picturesque artists' town surrounded by red rocks and known for its spirituality, vortex energy, and stunning hikes like Cathedral Rock.
10 most idyllic villages to visit in the United States
Discover 10 idyllic villages in the USA, from California to Vermont. Explore their unique charm, rich history, stunning nature, and vibrant arts scenes.