June weather forecast
St. Louis, MO

St. Louis experiences the official advent of summer in June. Temperatures continue their upward incline, creating warm, typically summery conditions. Average daytime temperatures climb to a pleasant 66.8°F (19.3°C), perfect for enjoying an outdoor picnic or a leisurely day boating on the Mississippi. The sunny days of June yield high UV indexes, encouraging residents to take necessary sun precautions. Intermittent spells of rainfall serve as a refreshing break from the summer heat.

Temperature

The shift into June in St. Louis is marked by a modest rise in the average high-temperature, moving from May's 76.3°F (24.6°C) to a still moderately hot 85.1°F (29.5°C). St. Louis's nighttime temperature in June falls to an average of 66.7°F (19.3°C).

Heat index

For June, the heat index is estimated at a hot 91.4°F (33°C). Ensure extra safety measures, heat exhaustion and heat cramps are likely. Continuous activity might result in heatstroke.
It is crucial to understand that heat index figures are for shade and gentle wind conditions. The direct sunshine could escalate the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Young ones generally face higher dangers than adults since they sweat less. Along with their large skin surface area compared totheir small bodies and increased heat production from their activities, the risks are heightened.

Humidity

In St. Louis, the average relative humidity in June is 67.1%.

Rainfall

In St. Louis, during June, the rain falls for 10 days and regularly aggregates up to 4.29" (109mm) of precipitation. Throughout the year, in St. Louis, there are 112.6 rainfall days, and 40.94" (1040mm) of precipitation is accumulated.

Snowfall

In St. Louis, snow does not fall in May through October.

Daylight

With an average of 14h and 48min of daylight, June has the longest days of the year in St. Louis.
On the first day of June in St. Louis, sunrise is at 5:37 am and sunset at 8:19 pm. On the last day of the month, sunrise is at 5:39 am and sunset at 8:29 pm CDT.

Sunshine

The average sunshine in June in St. Louis is 9.7h.

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 estimate of 8 to 10 represents a very high health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The UV index of 9 during June leads to these advisories:
Ensure you're protected; unprotected eyes and skin can get hurt in moments. 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. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. Despite the cloudy weather, sunscreen with a sun protection factor of at least 30 should be liberally applied and reapplied, including after a swim or outdoor activity.