July weather forecast and climate
St. Louis, MO

A beautiful twilight view of the Gateway Arch in St. Louis, Missouri, with a distant view of the city buildings mirrored in the waterfront
A beautiful twilight view of the Gateway Arch in St. Louis, Missouri, with a distant view of the city buildings mirrored in the waterfront
July in St. Louis is a tropical summer month, with temperature in the range of an average low of 71.1°F (21.7°C) and an average high of 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 evaluated at a torrid 102°F (38.9°C). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. With the 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 'feels like', 'real feel', 'felt air temperature', or 'apparent temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (wind, clothing, pregnancy). Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. 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. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

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

Rainfall

In July, in St. Louis, the rain falls for 8.9 days. Throughout July, 4.11" (104.4mm) of precipitation is accumulated. Throughout the year, in St. Louis, there are 112.6 rainfall days, and 40.96" (1040.3mm) of precipitation is accumulated.

Snowfall

In St. Louis snow does not fall in May through October.

Daylight

In St. Louis, the average length of the day is 14.5h.

Sunshine

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

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 of 8 to 10 symbolizes a very high threat to health from the exposure to the Sun's UV radiation for average individuals.
Note: The daily maximum UV index of 9 interpret into the following advice:
Take special precautions, as unprotected eyes and skin can be burned and damaged quickly. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. 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. A broad-spectrum sunscreen of SPF 30+ should be liberally applied and re-applied every two hours, and immediately after an outdoor workout or a swim.

What is the warmest month in St. Louis?

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

What is the temperature in July in St. Louis?

In St. Louis, in July, the average high-temperature is 89.1°F (31.7°C), and the average low-temperature is 71.1°F (21.7°C). In July, the average heat index (a.k.a. 'feels like', 'real feel'), that combines air temperature and relative humidity, is estimated at 102°F (38.9°C).

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

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

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

In July, in St. Louis, Missouri, the rain falls for 8.9 days. Throughout July, 4.11" (104.4mm) of precipitation is accumulated.

When it does not snow in St. Louis?

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

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

In July, the average length of the day in St. Louis, Missouri, is 14.5h.

What month has the most sunshine in St. Louis?

The month with the most sunshine in St. Louis, Missouri, is July, with an average of 10h of sunshine.

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

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

When is 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.

What is the UV index reading 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 vulnerability from unsafe exposure to the Sun's UV rays.
Average temperature in July - St. Louis, MO
  • Average high temperature in July: 31.7°C

The warmest month (with the highest average high temperature) is July (31.7°C).
The month with the lowest average high temperature is January (4.4°C).

  • Average low temperature in July: 21.7°C

The month with the highest average low temperature is July (21.7°C).
The coldest month (with the lowest average low temperature) is January (-4.6°C).

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%).

Average rainfall in July - St. Louis, MO
  • Average rainfall in July: 104.4mm

The wettest month (with the highest rainfall) is May (119.9mm).
The driest month (with the least rainfall) is February (56.9mm).

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).

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

The month with the highest snowfall is January (142.2mm).
Months with the least snowfall are May, June, July, August, September and October (0mm).

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).
Months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in July / Average sunshine in July - St. Louis, MO
  • Average daylight in July: 14.5h

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in July: 10h

The month with the most sunshine is July (Average sunshine: 10h).
The month with the least sunshine is December (Average sunshine: 4.2h).

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

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