May weather forecastAlton, MO
May
Weather in May
May, the last month of the spring in Alton, is a warm month, with an average temperature fluctuating between 57.6°F (14.2°C) and 77.2°F (25.1°C).Temperature
With the onset of May, Alton's average high-temperature experiences a rise, moving from April's refreshing 67.8°F (19.9°C) to a moderately hot 77.2°F (25.1°C). An average low-temperature of 57.6°F (14.2°C) is recorded during the nights in May.Humidity
March and May, with an average relative humidity of 79%, are the most humid months in Alton.Rainfall
May is the month with the most rainfall. Rain falls for 16.5 days and accumulates 4.25" (108mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In May, the average length of the day is 14h and 8min.On the first day of May, sunrise is at 6:10 am and sunset at 7:54 pm. On the last day of the month, sunrise is at 5:48 am and sunset at 8:18 pm CDT.
Sunshine
In May, the average sunshine is 8.7h.UV index
In Alton, the average daily maximum UV index in May is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for average individuals.Note: In May, a regular UV index of 6 translates into these guidelines:
Guard oneself from overexposure. Defence against sun injury is vital. Avoid direct Sun exposure and seek shade between 10 a.m. and 4 p.m., when UV radiation is at its peak, but keep in mind that not all shade structures provide complete protection. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Alton, MO
- Average high temperature in May: 77.2°F
The warmest month (with the highest average high temperature) is July (89.4°F).
The month with the lowest average high temperature is January (43.3°F).
- Average low temperature in May: 57.6°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (28.4°F).
Average pressure in May
Alton, MO
- Average pressure in May: 29.96"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in May
Alton, MO
- Average wind speed in May: 6.9mph
The windiest months (with the highest average wind speed) are January, February, March and April (8.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.3mph).
Average humidity in May
Alton, MO
- Average humidity in May: 79%
The months with the highest relative humidity are March and May (79%).
The month with the lowest relative humidity is October (72%).
Average rainfall in May
Alton, MO
- Average rainfall in May: 4.25"
The wettest month (with the highest rainfall) is May (4.25").
The driest month (with the least rainfall) is September (1.57").
Average rainfall days in May
Alton, MO
- Average rainfall days in May: 16.5 days
The month with the highest number of rainy days is May (16.5 days).
The month with the least rainy days is January (8.6 days).
Average snowfall in May
Alton, MO
- Average snowfall in May: 0"
The month with the highest snowfall is February (1.26").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in May
Alton, MO
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is February (2.8 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
Alton, MO
- Average daylight in May: 14h and 6min
The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in May: 8h and 42min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in May
Alton, MO
- Average sunshine days in May: 12.3 days
The month with the most sunshine days is December (19.6 days).
The month with the least sunshine days is May (12.3 days).
Average UV index in May
Alton, MO
- Average UV index in May: 6
The month with the highest UV index is June (UV index 7).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in May
Alton, MO
- Average cloud cover in May: 41
The month with the most cloud cover is March (Cloud cover 49).
The month with the least cloud cover is June (Cloud cover 29).
Average visibility in May
Alton, MO
- Average visibility in May: 5mi
The months with the highest visibility are January, February, March, April, June, August, September, October, November and December (6mi).
The months with the lowest visibility are May and July (5mi).
