O'Fallon
Missouri, USA
Long-term weather forecast
Long-term weather forecast

Monthly weather forecast and climate
O'Fallon, MO

January, like December, in O'Fallon, Missouri, is another cold winter month, with average temperature fluctuating between 23.7°F (-4.6°C) and 37.4°F (3°C). January is the coldest month, with an average high-temperature of 37.4°F (3°C) and an average low-temperature of 23.7°F (-4.6°C). Weather in January »

February, the last month of the winter, in O'Fallon, is another cold month, with temperature in the range of an average low of 27°F (-2.8°C) and an average high of 41.9°F (5.5°C). In O'Fallon, the average high-temperature in February is relatively the same as in January - a still cold 41.9°F (5.5°C). Weather in February »

March, the first month of the spring, in O'Fallon, is a fresh month, with average temperature varying between 54.1°F (12.3°C) and 37.9°F (3.3°C). In O'Fallon, Missouri, the average high-temperature in March increases, from a wintry 41.9°F (5.5°C) in February, to a cool 54.1°F (12.3°C). Weather in March »

April in O'Fallon, Missouri, is an enjoyable spring month, with temperature in the range of an average low of 47.3°F (8.5°C) and an average high of 65.3°F (18.5°C). In O'Fallon, the average high-temperature rises, from a cool 54.1°F (12.3°C) in March, to a comfortable 65.3°F (18.5°C). Weather in April »

May, the last month of the spring, in O'Fallon, is a moderately hot month, with average temperature fluctuating between 74.5°F (23.6°C) and 57°F (13.9°C). In May, the average high-temperature increases, from a comfortable 65.3°F (18.5°C) in April, to a moderately hot 74.5°F (23.6°C). Weather in May »

The first month of the summer, June, is also a moderately hot month in O'Fallon, Missouri, with temperature in the range of an average high of 83.8°F (28.8°C) and an average low of 66.2°F (19°C). In June, the average high-temperature increases, from 74.5°F (23.6°C) in May, to a still warm 83.8°F (28.8°C). Weather in June »

July in O'Fallon, Missouri, is a hot summer month, with average temperature varying between 87.1°F (30.6°C) and 68.5°F (20.3°C). With an average high-temperature of 87.1°F (30.6°C) and an average low-temperature of 68.5°F (20.3°C), July is the warmest month. The average heat index in July is evaluated at a torrid 101.5°F (38.6°C). Weather in July »

August, the last month of the summer, in O'Fallon, is another warm month, with temperature in the range of an average high of 85.5°F (29.7°C) and an average low of 66.6°F (19.2°C). In August, the average high-temperature is relatively the same as in July - a warm 85.5°F (29.7°C). Weather in August »

The first month of the autumn, September, is also a moderately hot month in O'Fallon, Missouri, with average temperature fluctuating between 60.1°F (15.6°C) and 79.5°F (26.4°C). In O'Fallon, the average high-temperature marginally drops, from 85.5°F (29.7°C) in August, to a still warm 79.5°F (26.4°C). Weather in September »

October, the same as September, is another comfortable autumn month in O'Fallon, Missouri, with average temperature ranging between max 66.2°F (19°C) and min 48.7°F (9.3°C). In October, the average high-temperature drops, from a warm 79.5°F (26.4°C) in September, to an enjoyable 66.2°F (19°C). Weather in October »

November, the last month of the autumn, in O'Fallon, is also a fresh month, with average temperature ranging between min 37.6°F (3.1°C) and max 53.2°F (11.8°C). In November, the average high-temperature drops, from an enjoyable 66.2°F (19°C) in October, to a cool 53.2°F (11.8°C). Weather in November »

The first month of the winter, December, is also a wintry month in O'Fallon, Missouri, with average temperature varying between 30.4°F (-0.9°C) and 41.9°F (5.5°C). In O'Fallon, the average high-temperature drops, from a fresh 53.2°F (11.8°C) in November, to a cold 41.9°F (5.5°C). Weather in December »

What is the coldest month in O'Fallon?

January is the coldest month, with an average high-temperature of 37.4°F (3°C) and an average low-temperature of 23.7°F (-4.6°C).

How much does it rain in O'Fallon?

Throughout the year, there are 132.3 rainfall days, and 21.06" (535mm) of precipitation is accumulated.

When does it snow in O'Fallon?

Months with snowfall are January through March, November and December.

How many days does it snow in O'Fallon?

Throughout the year, there are 19 snowfall days, and 4.13" (105mm) of snow is accumulated.

What is the month with the least sunshine in O'Fallon?

Months with the least sunshine are January and February, with an average of 4.7h of sunshine.

What is the month with the lowest UV index in O'Fallon?

Months with the lowest UV index in O'Fallon, Missouri, are January, February, November and December, with an average maximum UV index of 2.

When does it snow the most in O'Fallon?

February is the month with the most snowfall. Snow falls for 5.8 days and accumulates 1.61" (41mm) of snow.

When it does not snow in O'Fallon?

In O'Fallon, Missouri, snow does not fall in April through October.

What is the most humid month in O'Fallon?

May is the most humid month in O'Fallon, Missouri, with an average relative humidity of 79%.

What is the wettest month in O'Fallon?

May is the month with the most rainfall in O'Fallon, Missouri. Rain falls for 15.7 days and accumulates 2.76" (70mm) of precipitation.

What are the months with the highest UV index in O'Fallon?

Months with the highest UV index are May through August, with an average maximum UV index of 6.

When are the longest days in O'Fallon?

With an average of 14.9h of daylight, June has the longest days of the year in O'Fallon.

What month has the most sunshine in O'Fallon?

June has the most sunshine of the year in O'Fallon, with an average of 10.5h of sunshine.

What is the warmest month in O'Fallon?

With an average high-temperature of 87.1°F (30.6°C) and an average low-temperature of 68.5°F (20.3°C), July is the warmest month in O'Fallon, Missouri.

What is the least humid month in O'Fallon?

October is the least humid month in O'Fallon, Missouri, with an average relative humidity of 70%.

What is the driest month in O'Fallon?

The month with the least rainfall in O'Fallon, Missouri, is December when the rain falls for 7 days and typically collects 0.91" (23mm) of precipitation.

What is the month with the shortest days in O'Fallon?

With an average of 9.5h of daylight, December has the shortest days of the year in O'Fallon, Missouri.
Average temperature - O
Average rainfall - O

The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the lowest rainfall) is December (0.91").

Average rainfall days - O

The month with the highest number of rainy days is May (15.7 days).
The month with the lowest number of rainy days is February (6.8 days).

Average snowfall - O

The month with the highest snowfall is February (1.61").
Months with the lowest snowfall are April, May, June, July, August, September and October (0").

Average snowfall days - O

Months with the highest number of snowfall days are January and February (5.8 days).
Months with the lowest number of snowfall days are May, June, July, August, September and October (0 days).

Average daylight / Average sunshine - O

The month with the longest days is June (Average daylight: 14.9h).
The month with shortest days is December (Average daylight: 9.5h).

The month with most sunshine is June (Average sunshine: 10.5h).
Months with least sunshine are January and February (Average sunshine: 4.7).

Average UV index - O