in St. Louis
is a tropical summer month, with an average temperature fluctuating between 71.1°F (21.7°C) and 89.1°F (31.7°C).
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).
In July, the average heat index is evaluated at a sweltering 102°F (38.9°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. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.Note
: The heat index, also known as 'real feel', 'apparent temperature', 'felt air temperature', or 'feels like', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. This effect is individual, with diverse people perceiving weather differently for numerous reasons (pregnancy, clothing, wind), and activity. 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 particularly important for children. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. 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.
In St. Louis, the average relative humidity in July is 68%.
In St. Louis, Missouri, it is raining for 8.9 days, with typically 4.11" (104.4mm) of accumulated precipitation. Throughout the year, in St. Louis, Missouri, there are 112.6 rainfall days, and 40.96" (1040.3mm) of precipitation is accumulated.
In St. Louis, snow does not fall in May
In St. Louis, 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.
With an average of 10h of sunshine, July has the most sunshine of the year in St. Louis, Missouri.
The months with the highest UV index in St. Louis are June
, with an average maximum UV index of 9. A UV Index estimate of 8 to 10 represents a very high health hazard from unprotected exposure to Sun's UV rays for average individuals.Note
: The daily maximum UV index of 9 in July 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. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. 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.