Contents
- Weather in May
- Frequently asked questions
- Average temperature in May
- Average pressure in May
- Average wind speed in May
- Average humidity in May
- Average rainfall in May
- Average rainfall days in May
- Average snowfall in May
- Average snowfall days in May
- Average daylight in May
- Average sunshine in May
- Average sunshine days in May
- Average UV index in May
- Average cloud cover in May
- Average visibility in May
Weather in May
Temperature
With the onset of May, Helena's weather sees a temperature rise, transitioning from a chilly 47.8°F (8.8°C) in April to a moderate 59.4°F (15.2°C). Helena experiences a consistent, yet significant, drop from daily highs to a low-temperature of 36.9°F (2.7°C) throughout May.Humidity
In Helena, Montana, the average relative humidity in May is 62%.Rainfall
In Helena, in May, it is raining for 15.8 days, with typically 1.5" (38mm) of accumulated precipitation. In Helena, during the entire year, the rain falls for 123.7 days and collects up to 12.4" (315mm) of precipitation.Snowfall
January through May, September through December are months with snowfall in Helena, Montana. May is the last month it regularly snows in Helena. During 1.3 snowfall days, in May, Helena aggregates 0.67" (17mm) of snow. In Helena, during the entire year, snow falls for 80.4 days and aggregates up to 34.88" (886mm) of snow.Daylight
The average length of the day in May is 15h and 2min.On the first day of the month, sunrise is at 6:11 am and sunset at 8:38 pm. On the last day of May, in Helena, sunrise is at 5:38 am and sunset at 9:13 pm MDT.
Sunshine
In May, the average sunshine is 10.3h.UV index
In May, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for average individuals.Note: An average UV index of 4 in May transforms into this advice:
Take necessary precautions - Protection from skin and eye injury is mandatory. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation. Be aware! The intensity of the Sun's UV radiation can be amplified nearly twice due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Helena in May?
What is the average humidity in May in Helena?
How much does it rain in Helena in May?
What is the last month it snows in Helena?
How many hours of daylight does Helena have in May?
When is the sunrise / sunset in May in Helena?
How many hours of sunshine does Helena have in May?
What is the UV index reading in May in Helena?
Average temperature in May
Helena, MT
- Average high temperature in May: 59.4°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is December (27.7°F).
- Average low temperature in May: 36.9°F
The month with the highest average low temperature is July (50.4°F).
The coldest month (with the lowest average low temperature) is December (14.2°F).
Average pressure in May
Helena, MT
- Average pressure in May: 29.95"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in May
Helena, MT
- Average wind speed in May: 5.8mph
The windiest month (with the highest average wind speed) is November (7.1mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity in May
Helena, MT
- Average humidity in May: 62%
The month with the highest relative humidity is January (85%).
The months with the lowest relative humidity are July and August (46%).
Average rainfall in May
Helena, MT
- Average rainfall in May: 1.5"
The wettest month (with the highest rainfall) is June (2.01").
The driest months (with the least rainfall) are January and December (0.63").
Average rainfall days in May
Helena, MT
- Average rainfall days in May: 15.8 days
The month with the highest number of rainy days is May (15.8 days).
The month with the least rainy days is November (7 days).
Average snowfall in May
Helena, MT
- Average snowfall in May: 0.67"
The month with the highest snowfall is February (6.18").
The months with the least snowfall are June, July and August (0").
Average snowfall days in May
Helena, MT
- Average snowfall days in May: 1.3 days
The month with the highest number of snowfall days is February (16.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in May /
Average sunshine in May
Helena, MT
- Average daylight in May: 15h and 0min
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 2min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is January (Average sunshine: 5h and 36min).
Average sunshine days in May
Helena, MT
- Average sunshine days in May: 12.2 days
The month with the most sunshine days is July (20.5 days).
The month with the least sunshine days is April (9.8 days).
Average UV index in May
Helena, MT
- Average UV index in May: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in May
Helena, MT
- Average cloud cover in May: 33
The month with the most cloud cover is February (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in May
Helena, MT
- Average visibility in May: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).
Helena, Montana, USA
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