July weather forecast
St. Louis, MO

A beautiful twilight over the Gateway Arch in St. Louis, Missouri
A beautiful twilight over the Gateway Arch in St. Louis, Missouri

Weather in July

July is a hot summer month in St. Louis, Missouri, with an average temperature fluctuating between 71.1°F (21.7°C) and 89.1°F (31.7°C).

Temperature

The warmest month in St. Louis is July, with an average high-temperature of 89.1°F (31.7°C) and an average low-temperature of 71.1°F (21.7°C).

Heat index

In July, the average heat index is estimated at a very hot 102.2°F (39°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Note that heat index values are valued for light wind and location in the shade. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'feels like', 'felt air temperature', or 'real feel', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. Additional factors like metabolic differences, wind, pregnancy, and activity influence one's weather impression. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body normally cools itself by perspiration. Excessive warmth is eliminated from the body by evaporation of sweat. A higher relative humidity affects normal body cooling by reducing the evaporation rate, subsequently lowering the rate at which the body cools and increasing the perception of heat. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

In July, the average relative humidity in St. Louis is 68%.

Rainfall

In St. Louis, in July, during 8.9 rainfall days, 4.09" (104mm) of precipitation is typically accumulated. Throughout the year, in St. Louis, there are 112.6 rainfall days, and 40.94" (1040mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall in St. Louis.

Daylight

In St. Louis, Missouri, the average length of the day in July is 14h and 33min.
On the first day of July in St. Louis, sunrise is at 5:40 am and sunset at 8:29 pm. On the last day of the month, sunrise is at 6:01 am and sunset at 8:12 pm CDT.

Sunshine

July has the most sunshine of the year in St. Louis, Missouri, with an average of 10h of sunshine.

UV index

June through August, with an average maximum UV index of 9, are months with the highest UV index in St. Louis. A UV Index estimate of 8 to 10 represents a very high health vulnerability from exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 9 in July transform into the following instructions:
Take extra precautions. Protection against sun damage is required. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise.
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FAQ

What is the warmest month in St. Louis?

The warmest month in St. Louis, Missouri, is July, with an average high-temperature of 89.1°F (31.7°C) and an average low-temperature of 71.1°F (21.7°C).

What is the temperature in July in St. Louis?

The average high-temperature, in July, in St. Louis, is 89.1°F (31.7°C), while the average low-temperature is 71.1°F (21.7°C). The average heat index (a.k.a. 'felt air temperature', 'real feel'), which factors the actual air temperature with the relative humidity, in July is estimated at 102.2°F (39°C).

What is the average humidity in July in St. Louis?

The average relative humidity in July in St. Louis, Missouri, is 68%.

How much does it rain in St. Louis in July?

In July, in St. Louis, the rain falls for 8.9 days. Throughout July, 4.09" (104mm) of precipitation is accumulated.

When it does not snow in St. Louis?

May through October are months without snowfall in St. Louis, Missouri.

How many hours of daylight does St. Louis have in July?

The average day length in July in St. Louis is 14h and 33min.

What time are sunrise and sunset in July in St. Louis?

In July, on the first day of the month, sunrise is at 5:40 am and sunset at 8:29 pm. On the last day of the month, in St. Louis, sunrise is at 6:01 am and sunset at 8:12 pm CDT.

What month has the most sunshine in St. Louis?

With an average of 10h of sunshine, July has the most sunshine of the year in St. Louis.

How long on average sun shines in July in St. Louis?

In July, the average sunshine duration in St. Louis, Missouri, is 10h.

What are the months with the highest UV index in St. Louis?

June through August, with an average maximum UV index of 9, are months with the highest UV index.

How high is the UV index in July in St. Louis?

In July, the average daily maximum UV index in St. Louis is 9. A UV Index of 8 to 10 symbolizes a very high health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average UV index

Average temperature in July
St. Louis, MO

Average temperature in July - St. Louis, MO
  • Average high temperature in July: 89.1°F

The warmest month (with the highest average high temperature) is July (89.1°F).
The month with the lowest average high temperature is January (39.9°F).

  • Average low temperature in July: 71°F

The month with the highest average low temperature is July (71°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).

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Average humidity in July
St. Louis, MO

Average humidity in July - St. Louis, MO
  • Average humidity in July: 68%

The month with the highest relative humidity is December (75.8%).
The month with the lowest relative humidity is April (63.5%).

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Average rainfall in July
St. Louis, MO

Average rainfall in July - St. Louis, MO
  • Average rainfall in July: 4.1"

The wettest month (with the highest rainfall) is May (4.7").
The driest month (with the least rainfall) is February (2.2").

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Average rainfall days in July
St. Louis, MO

Average rainfall days in July - St. Louis, MO
  • Average rainfall days in July: 8.9 days

The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is September (7.4 days).

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Average snowfall in July
St. Louis, MO

Average snowfall in July - St. Louis, MO
  • Average snowfall in July: 0"

The month with the highest snowfall is January (5.6").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in July
St. Louis, MO

Average snowfall days in July - St. Louis, MO
  • Average snowfall days in July: 0 days

The month with the highest number of snowfall days is January (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in July /
Average sunshine in July
St. Louis, MO

Average daylight in July / Average sunshine in July - St. Louis, MO
  • Average daylight in July: 14h and 4min

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 30min).

  • Average sunshine in July: 10h and 0min

The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).

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Average UV index in July
St. Louis, MO

Average UV index in July - St. Louis, MO
  • Average UV index in July: 9

The months with the highest UV index are June, July and August (UV index 9).
The months with the lowest UV index are January and December (UV index 2).

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