May weather forecastDecker, MT
May
Weather in May
May, the last month of the spring in Decker, is an enjoyable month, with an average temperature ranging between min 43.5°F (6.4°C) and max 63.7°F (17.6°C).Temperature
The arrival of May brings a change in Decker's weather, with average high-temperatures moving from April's fresh 53.1°F (11.7°C) to a refreshing 63.7°F (17.6°C). An average low-temperature of 43.5°F (6.4°C) marks the nights throughout May.Humidity
In Decker, the average relative humidity in May is 61%.Rainfall
May is the month with the most rainfall. Rain falls for 18 days and accumulates 2.64" (67mm) of precipitation.Snowfall
Months with snowfall are January through May, September through December. May is the last month it regularly snows in Decker. During 1.3 snowfall days, in May, Decker aggregates 0.87" (22mm) of snow. In Decker, during the entire year, snow falls for 65.3 days and aggregates up to 28.82" (732mm) of snow.Daylight
In Decker, the average length of the day in May is 14h and 53min.On the first day of May, sunrise is at 5:55 am and sunset at 8:13 pm. On the last day of the month, sunrise is at 5:23 am and sunset at 8:46 pm MDT.
Sunshine
The average sunshine in May is 10.5h.UV index
In May, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: In May, a daily UV index of 5 turns into the following recommendations:
Act with care - Obligation to protect against skin and eye damage is highlighted. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Decker, MT
- Average high temperature in May: 63.7°F
The warmest month (with the highest average high temperature) is July (85.5°F).
The month with the lowest average high temperature is December (31.1°F).
- Average low temperature in May: 43.5°F
The month with the highest average low temperature is July (61.5°F).
The coldest months (with the lowest average low temperature) are January and February (16.2°F).
Average pressure in May
Decker, MT
- Average pressure in May: 29.91"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
Decker, MT
- Average wind speed in May: 8.6mph
The windiest month (with the highest average wind speed) is April (9.1mph).
The calmest months (with the lowest average wind speed) are July and December (6.8mph).
Average humidity in May
Decker, MT
- Average humidity in May: 61%
The months with the highest relative humidity are January and February (79%).
The month with the lowest relative humidity is August (40%).
Average rainfall in May
Decker, MT
- Average rainfall in May: 2.64"
The wettest month (with the highest rainfall) is May (2.64").
The driest month (with the least rainfall) is December (0.67").
Average rainfall days in May
Decker, MT
- Average rainfall days in May: 18 days
The month with the highest number of rainy days is May (18 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in May
Decker, MT
- Average snowfall in May: 0.87"
The month with the highest snowfall is February (5.2").
The months with the least snowfall are June, July and August (0").
Average snowfall days in May
Decker, MT
- Average snowfall days in May: 1.3 days
The month with the highest number of snowfall days is February (14.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in May /
Average sunshine in May
Decker, MT
- Average daylight in May: 14h and 54min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in May: 10h and 30min
The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 5h and 42min).
Average sunshine days in May
Decker, MT
- Average sunshine days in May: 9.6 days
The month with the most sunshine days is September (18.2 days).
The month with the least sunshine days is May (9.6 days).
Average UV index in May
Decker, MT
- Average UV index in May: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in May
Decker, MT
- Average cloud cover in May: 31
The month with the most cloud cover is February (Cloud cover 41).
The months with the least cloud cover are July and August (Cloud cover 14).
Average visibility in May
Decker, 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).





