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 (20.8°C). 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

In St. Louis, August's average high-temperature stands at a still hot 88°F (31.1°C), closely related to the preceding month. St. Louis's average low-temperature during August nights is observed to be an agreeable 69.4°F (20.8°C).

Heat index

Throughout August, the heat index is evaluated at a sweltering 100.4°F (38°C). Ensure extra safety measures, heat exhaustion and heat cramps are likely. Continuous activity might result in heatstroke.
It is worth noting that heat index values are gauged for conditions in the shade and light breezes. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is a metric representing the sensation of warmth when air temperature and moisture come together. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. 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 extremely significant for children. Kids are usually more vulnerable than adults, given their lesser sweating ability. Along with their larger skin surface relative to their small stature and the excess heat due to their activity, their risk is amplified.
One way the human body deals with excessive warmth is by perspiring and allowing sweat to evaporate. Elevated relative humidity disrupts typical body cooling by reducing the evaporation rate, consequently decreasing the body's cooling rate and enhancing the feeling of heat. When heat surpasses the body's release mechanisms, dehydration and overheating risks become pronounced.

Humidity

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

Rainfall

In St. Louis, in August, it is raining for 8.2 days, with typically 2.99" (76mm) of accumulated precipitation. In St. Louis, Missouri, 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 St. Louis, the average length of the day in August is 13h and 37min.
On the first day of August in St. Louis, sunrise is at 6:03 am and sunset at 8:11 pm. On the last day of the month, sunrise is at 6:29 am and sunset at 7:31 pm CDT.

Sunshine

In August, the average sunshine 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. A UV Index of 8 to 10 symbolizes a very high health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: A typical high UV index of 9 in August suggests the following recommendations:
Refrain from exposing skin and eyes. Without protection, they can get damaged rapidly. Make an effort to avoid direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation, and note that objects like parasols or canopies might not offer full sun protection. Tightly woven clothing, when worn loosely, shields effectively against the Sun. After a swim or outdoor exercise, one should liberally reapply broad-spectrum sunscreen with a sun protection factor of 30 or higher.