, the first month of the summer, in St. Louis
, is still a warm month, with average temperature fluctuating between 66.7°F (19.3°C) and 85.1°F (29.5°C).
In St. Louis, Missouri
, the average high-temperature in June slightly increases, from 76.3°F (24.6°C) in May
, to a still moderately hot 85.1°F (29.5°C). In June, in St. Louis, the average low-temperature is 66.7°F (19.3°C).
The average heat index is evaluated at a hot 91.8°F (33.2°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', 'feels like', 'apparent temperature', or 'felt air temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (pregnancy, metabolic differences, wind). 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 especially crucial for babies and toddlers. 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.
In June, the average relative humidity in St. Louis is 67.1%.
In St. Louis, in June, during 10 rainfall days, 4.28" (108.7mm) of precipitation is typically accumulated. In St. Louis, during the entire year, the rain falls for 112.6 days and collects up to 40.96" (1040.3mm) of precipitation.
May through October
are months without snowfall in St. Louis.
June has the longest days of the year in St. Louis, with an average of 14.8h of daylight.
The average sunshine in St. Louis is 9.7h.
June through August
, with an average maximum UV index of 9, are months with the highest UV index in St. Louis. A UV Index value of 8 to 10 symbolizes a very high threat to health from the exposure to the Sun's UV radiation for the ordinary person.Note
: The daily maximum UV index of 9 interpret into the following advice:
Take special precautions, as unprotected skin can be damaged and can burn 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.