MOUNT VERNON, ILLINOIS

This climate is characterized by relatively high temperatures and evenly distributed precipitation throughout the year. This climate type is found on the eastern sides of the continents between 20° and 35° N and S latitude. In summer, these regions are largely under the influence of moist, maritime airflow from the western side of the subtropical anticyclonic cells over low-latitude ocean waters. Temperatures are high and can lead to warm, oppressive nights. Summers are usually somewhat wetter than winters, with much of the rainfall coming from convectional thunderstorm activity; tropical cyclones also enhance warm-season rainfall in some regions. The coldest month is usually quite mild, although frosts are not uncommon, and winter precipitation is derived primarily from frontal cyclones along the polar front.

The Köppen Climate Classification subtype for this climate is "Cfa". (Humid Subtropical Climate).

The average temperature for the year in Mount Vernon is 56.0°F (13.3°C). The warmest month, on average, is July with an average temperature of 78.0°F (25.6°C). The coolest month on average is January, with an average temperature of 32.0°F (0°C).

The highest recorded temperature in Mount Vernon is 114.0°F (45.6°C), which was recorded in July. The lowest recorded temperature in Mount Vernon is -22.0°F (-30°C), which was recorded in February.

The average amount of precipitation for the year in Mount Vernon is 41.6" (1056.6 mm). The month with the most precipitation on average is May with 4.2" (106.7 mm) of precipitation. The month with the least precipitation on average is February with an average of 2.5" (63.5 mm). In terms of liquid precipitation, there are an average of 73.8 days of rain, with the most rain occurring in June with 7.0 days of rain, and the least rain occurring in October with 5.1 days of rain.

In Mount Vernon, there's an average of 13.8" of snow (0 cm). The month with the most snow is February, with 4.0" of snow (10.2 cm).