May weather forecastLewistown, MT
May
Weather in May
May signifies a period of increased weather activity with the transition of seasons. With temperatures ascending to 58.5°F (14.7°C), indicating a significant departure from April, the warmth becomes noticeable. A peak rainfall volume of 3.39" (86mm) documents the heaviest downpour for the year. Longer daylight hours coupled with more sunshine manifest the imminent arrival of summer. Following April’s trend, the city witnesses a further decrease of relative humidity.Temperature
May's arrival coincides with a rise in the average high-temperature, moving from April's frosty 47.8°F (8.8°C) to a refreshing 58.5°F (14.7°C). Throughout the month of May, Lewistown witnesses an average temperature of 40.1°F (4.5°C).Humidity
In Lewistown, the average relative humidity in May is 65%.Rainfall
May is the month with the most rainfall. Rain falls for 19.3 days and accumulates 3.39" (86mm) of precipitation.Snowfall
Months with snowfall are January through June, September through December. In Lewistown, in May, snow falls for 2.4 days, with typically accumulated 2.48" (63mm) of snow. In Lewistown, during the entire year, snow falls for 83.4 days and aggregates up to 45.51" (1156mm) of snow.Daylight
In May, the average length of the day is 15h and 6min.On the first day of May, sunrise is at 6:00 am and sunset at 8:29 pm. On the last day of the month, sunrise is at 5:26 am and sunset at 9:04 pm MDT.
Sunshine
In May, the average sunshine is 10h.UV index
In Lewistown, the average daily maximum UV index in May is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: The UV index of 4 in May translates into these instructions:
Be vigilant - Preventing sunburn is recommended. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Lewistown, MT
- Average high temperature in May: 58.5°F
The warmest month (with the highest average high temperature) is July (78.8°F).
The months with the lowest average high temperature are February and December (29.1°F).
- Average low temperature in May: 40.1°F
The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is February (15.3°F).
Average pressure in May
Lewistown, MT
- Average pressure in May: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in May
Lewistown, MT
- Average wind speed in May: 8.8mph
The windiest months (with the highest average wind speed) are January, April and October (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).
Average humidity in May
Lewistown, MT
- Average humidity in May: 65%
The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is August (47%).
Average rainfall in May
Lewistown, MT
- Average rainfall in May: 3.39"
The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is December (0.71").
Average rainfall days in May
Lewistown, MT
- Average rainfall days in May: 19.3 days
The month with the highest number of rainy days is May (19.3 days).
The month with the least rainy days is January (5.4 days).
Average snowfall in May
Lewistown, MT
- Average snowfall in May: 2.48"
The month with the highest snowfall is April (9.13").
The months with the least snowfall are July and August (0").
Average snowfall days in May
Lewistown, MT
- Average snowfall days in May: 2.4 days
The month with the highest number of snowfall days is February (15.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in May /
Average sunshine in May
Lewistown, MT
- Average daylight in May: 15h and 6min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in May: 10h and 0min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 30min).
Average sunshine days in May
Lewistown, MT
- Average sunshine days in May: 8.9 days
The month with the most sunshine days is September (19.3 days).
The month with the least sunshine days is April (8.3 days).
Average UV index in May
Lewistown, MT
- Average UV index in May: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).
Average cloud cover in May
Lewistown, MT
- Average cloud cover in May: 36
The month with the most cloud cover is February (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 16).
Average visibility in May
Lewistown, MT
- Average visibility in May: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
