May weather forecastSt. Louis, MO

A beautiful twilight over the Gateway Arch in St. Louis, Missouri

May

Weather in May

May dawns with improved weather conditions and temperatures, making it ideal for outdoor activities and explorations. The high temperatures rise further, granting the city a pleasant, slightly warm ambiance. The city basks in the highest average temperatures of 57.2°F (14°C) experienced this year. The onset of summer ushers in better lit and longer days in St. Louis. However, humidity levels display an upward trend, adding moisture to the warming air.

Temperature

A minor escalation in the average high-temperature is seen in St. Louis with the onset of May, moving from a comfortable 67.5°F (19.7°C) in April to a moderately hot 76.3°F (24.6°C). During May, the nighttime temperature in St. Louis averages of 57.2°F (14°C).

Humidity

In May, the average relative humidity in St. Louis is 66.5%.

Rainfall

May is the month with the most rainfall in St. Louis. Rain falls for 11.9 days and accumulates 4.72" (120mm) of precipitation.

Snowfall

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

Daylight

In St. Louis, the average length of the day in May is 14h and 17min.
On the first day of May in St. Louis, sunrise is at 6:02 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 5:38 am and sunset at 8:19 pm CDT.

Sunshine

In St. Louis, the average sunshine in May is 8.6h.

UV index

In May, the average daily maximum UV index in St. Louis is 8. A UV Index estimate of 8 to 10 represents a very high health risk from unsafe exposure to UV radiation for ordinary individuals.
Note: The average daily UV index of 8 in May transforms into the following instructions:
It is crucial to take precautions; skin and eyes can get damaged if left unprotected. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.

Updated: Aug 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

In St. Louis, 76.3°F (24.6°C) is the average high-temperature and 57.2°F (14°C) is the average low-temperature during May.

In May, the average relative humidity is 66.5%.

The month with the most rainfall is May, when the rain falls for 11.9 days and typically aggregates up to 4.72" (120mm) of precipitation.

In St. Louis, in May, it is raining for 11.9 days, with typically 4.72" (120mm) of accumulated precipitation.

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

In May, it doesn't snow. April is the latest month when it typically snows.

In May, the average day length is 14h and 17min.

In May, on the first day of the month, sunrise is at 6:02 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 5:38 am and sunset at 8:19 pm CDT.

The average sunshine duration in May is 8.6h.

The average daily maximum UV index in May is 8. A UV Index estimate of 8 to 10 represents a very high hazard to health from unprotected exposure to UV radiation.

Today

Tomorrow

Long-term

Year J F M A May J J A S O N D

Apr

May

Jun

Average high temperature

67.4°F

76.3°F

85.1°F

Average low temperature

Average humidity

Average rainfall

Average rainfall days

11.3

11.9

Average snowfall

0.4"

Average snowfall days

Average daylight

Average sunshine

Average UV index

Average temperature in May
St. Louis, MO

Average high temperature in May: 76.3°F

The warmest month (with the highest average high temperature) is July (89.1°F).
The month with the lowest average high temperature is January (39.9°F).

Average low temperature in May: 57.2°F

The month with the highest average low temperature is July (71°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).

Average humidity in May
St. Louis, MO

Average humidity in May: 66.5%

The month with the highest relative humidity is December (75.8%).
The month with the lowest relative humidity is April (63.5%).

Average rainfall in May
St. Louis, MO

Average rainfall in May: 4.7"

The wettest month (with the highest rainfall) is May (4.7").
The driest month (with the least rainfall) is February (2.2").

Average rainfall days in May
St. Louis, MO

Average rainfall days in May: 11.9 days

The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is September (7.4 days).

Average snowfall in May
St. Louis, MO

Average snowfall in May: 0"

The month with the highest snowfall is January (5.6").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in May
St. Louis, MO

Average snowfall days in May: 0 days

The month with the highest number of snowfall days is January (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in May /
Average sunshine in May
St. Louis, MO

Average daylight in May: 14h and 18min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

Average sunshine in May: 8h and 36min

The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).

Average UV index in May
St. Louis, MO

Average UV index in May: 8

The months with the highest UV index are June, July and August (UV index 9).
The months with the lowest UV index are January and December (UV index 2).