August weather forecast
St. Louis, MO

The weather in August carries forward the warmth and high humidity of July. Despite a slight dip in temperatures, the average remains notably high at 69.4°F. St. Louis continues to bask in long daylight hours, frequently punctuated by sudden bursts of summer rainstorms. The residency starts planning for the transition towards the autumn season. The prolonged summer augments the enjoyment of the city's many outdoor parks and amenities.

Temperature

August's advent in St. Louis notes a subtle adjustment in average high-temperature to a still tropical 88°F from July. St. Louis witnesses an average low-temperature of 69.4°F throughout the month of August.

Heat index

August's heat index is appraised at a sweltering 100.4°F. Incorporate extra safety measures to avoid heat exhaustion and heat cramps. Continuous activity could provoke heatstroke.
When considering the heat index, it's pivotal to note it is for shade and mild wind conditions. Direct sunlight can cause a surge in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'real feel', blends air temperature and moisture content to represent the felt temperature to humans. Factors such as metabolic variations, being pregnant, and physical activity can impact an individual's weather perception. Should you be directly under the sun, anticipate a possible increase in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for babies and toddlers. Children often miss understanding the importance of rest and rehydration. Thirst usually appears late during dehydration - therefore, maintaining hydration, particularly during long physical activities, is essential.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. When air moisture content is high, the cooling process through evaporation is not as efficient, leading to an ineffective body cooling process and a feeling of overheating. Excessive heat gain, when not shed effectively by the body, can result in increasing body temperatures and related hazards.

Humidity

In St. Louis, the average relative humidity in August is 70%.

Rainfall

In St. Louis, Missouri, in August, during 8.2 rainfall days, 2.99" of precipitation is typically accumulated. In St. Louis, during the entire year, the rain falls for 112.6 days and collects up to 40.94" of precipitation.

Snowfall

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

Daylight

In August, the average length of the day in St. Louis is 13h and 37min.
On the first day of the month, sunrise is at 6:02 am and sunset at 8:11 pm. On the last day of August, in St. Louis, Missouri, sunrise is at 6:29 am and sunset at 7:33 pm CDT.

Sunshine

The average sunshine in August in St. Louis is 8.7h.

UV index

June through August, with an average maximum UV index of 9, are months with the highest UV index in St. Louis, Missouri. A UV Index estimate of 8 to 10 represents a very high health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: The daily high UV index of 9 in August translates into this advice:
Swift harm can befall unprotected skin and eyes. Prioritize safety. UV radiation from the sun is at its strongest between 10 a.m. and 4 p.m. Try to limit direct exposure during these hours. Boost your sun resistance with garments that are densely woven yet spacious. Applying and reapplying a broad-spectrum sunscreen with a minimum SPF 30 after every two hours, outdoor workout, or swim is recommended.