July weather forecast
St. Louis, MO

July is the warmest month of the year in St. Louis. High temperatures reach their zenith in this month, registering an all-year high of 71°F (21.7°C). Residents and tourists alike eagerly anticipate the quintessential southern summer, filled with sunny days and warm nights. The resurgence of humidity necessitates regular hydration. Yet, despite the humidity, July proves to be a popular month for outdoor concerts and music festivals in the city.

Temperature

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

Heat index

The heat index value during July is estimated at a very hot 102.2°F (39°C). More preventive actions are needed, risk of heat exhaustion and heat cramps is significant. Prolonged activity may trigger heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunlight may make the heat index values climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', binds temperature metrics with humidity values to give a sense of the actual warmth. The impact of temperature is individual, as people's perception of weather may change based on their body mass, height, and physical activity. Recognize that direct exposure to the sun can escalate the heat effect, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are extremely significant for babies and toddlers. Youngsters typically face more danger than adults since they sweat less. Their larger skin surface compared to their small bodies and heightened heat production from their activities augment their vulnerability.
Perspiration is the body's default response to elevated temperatures, as it promotes the evaporation of sweat to achieve cooling. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. The body faces dehydration threats when its cooling efforts are outpaced by excessive heat gain.

Humidity

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

Rainfall

In July, in St. Louis, the rain falls for 8.9 days. Throughout July, 4.09" (104mm) of precipitation is accumulated. In St. Louis, during the entire year, the rain falls for 112.6 days and collects up to 40.94" (1040mm) of precipitation.

Snowfall

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

Daylight

In July, the average length of the day in St. Louis, Missouri, is 14h and 33min.
On the first day of the month, sunrise is at 5:40 am and sunset at 8:29 pm. On the last day of July, in St. Louis, sunrise is at 6:02 am and sunset at 8:12 pm CDT.

Sunshine

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

UV index

The months with the highest UV index in St. Louis are June through August, with an average maximum UV index of 9. A UV Index of 8 to 10 symbolizes a very high health vulnerability from unsafe exposure to UV radiation for the average person.
Note: The maximum UV index of 9 during July leads to these instructions:
Always take safety measures. The skin and eyes are at risk if left exposed. 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. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. A sunscreen boasting a minimum SPF of 30 should be generously applied and reapplied even on cloudy days, post swim or outdoor exercise.