May weather forecast
Grantsdale, MT

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Weather in May

The last month of the spring, May, is a refreshing month in Grantsdale, Montana, with an average temperature fluctuating between 56.7°F (13.7°C) and 33.4°F (0.8°C).

Temperature

In Grantsdale, the average high-temperature in May rises, from a frosty 43.5°F (6.4°C) in April, to a mild 56.7°F (13.7°C). Grantsdale anticipates a considerable cooling off from the daytime high to an average minimum temperature of 33.4°F (0.8°C) in May.

Humidity

The average relative humidity in May in Grantsdale is 71%.

Rainfall

In Grantsdale, in May, during 19.5 rainfall days, 1.97" (50mm) of precipitation is typically accumulated. Throughout the year, there are 163.6 rainfall days, and 20.83" (529mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall. May is the last month it regularly snows. During 2.3 snowfall days, in May, Grantsdale aggregates 0.67" (17mm) of snow. Throughout the year, there are 101.1 snowfall days, and 59.17" (1503mm) of snow is accumulated.

Daylight

The average length of the day in May in Grantsdale is 15h and 0min.
On the first day of the month, sunrise is at 6:21 am and sunset at 8:45 pm. On the last day of May, sunrise is at 5:48 am and sunset at 9:20 pm MDT.

Sunshine

In May, the average sunshine is 10.4h.

UV index

In Grantsdale, the average daily maximum UV index in May is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: An average UV index of 4 in May transforms into this advice:
Ensure safety - Sun damage prevention is strongly urged. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Updated: Aug 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are May temperatures?

The average high-temperature, in May, in Grantsdale, is 56.7°F (13.7°C), while the average low-temperature is 33.4°F (0.8°C).

What is the average humidity in May?

The average relative humidity in May is 71%.

How much does it rain in May?

In May, the rain falls for 19.5 days. Throughout May, 1.97" (50mm) of precipitation is accumulated.

What is the last month it snows?

May is the last month it regularly snows. During 2.3 snowfall days, in May, Grantsdale aggregates 0.67" (17mm) of snow.

How many hours of daylight does Grantsdale have in May?

In May, the average day length is 15h and 0min.

When are sunrise and sunset in May?

On the first day of May, sunrise is at 6:21 am and sunset at 8:45 pm. On the last day of the month, sunrise is at 5:48 am and sunset at 9:20 pm MDT.

How many hours of sunshine does Grantsdale have in May?

In May, the average sunshine duration is 10.4h.

What is the UV index reading in May?

The average daily maximum UV index in May is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Grantsdale, MT

Average temperature in May - Grantsdale, MT
  • Average high temperature in May: 56.7°F

The warmest month (with the highest average high temperature) is July (77°F).
The month with the lowest average high temperature is December (26.8°F).

  • Average low temperature in May: 33.4°F

The month with the highest average low temperature is August (46.9°F).
The coldest month (with the lowest average low temperature) is December (14°F).

Average pressure in May
Grantsdale, MT

Average pressure in May - Grantsdale, MT
  • Average pressure in May: 29.96"Hg

The month with the highest atmospheric pressure is January (30.21"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in May
Grantsdale, MT

Average wind speed in May - Grantsdale, MT
  • Average wind speed in May: 4.5mph

The windiest month (with the highest average wind speed) is January (5.3mph).
The calmest month (with the lowest average wind speed) is August (4.1mph).

Average humidity in May
Grantsdale, MT

Average humidity in May - Grantsdale, MT
  • Average humidity in May: 71%

The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is August (50%).

Average rainfall in May
Grantsdale, MT

Average rainfall in May - Grantsdale, MT
  • Average rainfall in May: 1.97"

The wettest months (with the highest rainfall) are February and April (2.36").
The driest month (with the least rainfall) is August (0.75").

Average rainfall days in May
Grantsdale, MT

Average rainfall days in May - Grantsdale, MT
  • Average rainfall days in May: 19.5 days

The month with the highest number of rainy days is May (19.5 days).
The month with the least rainy days is July (8 days).

Average snowfall in May
Grantsdale, MT

Average snowfall in May - Grantsdale, MT
  • Average snowfall in May: 0.67"

The month with the highest snowfall is February (13.03").
The months with the least snowfall are June, July and August (0").

Average snowfall days in May
Grantsdale, MT

Average snowfall days in May - Grantsdale, MT
  • Average snowfall days in May: 2.3 days

The month with the highest number of snowfall days is February (19.3 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in May /
Average sunshine in May
Grantsdale, MT

Average daylight in May / Average sunshine in May - Grantsdale, MT
  • Average daylight in May: 15h and 0min

The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).

  • Average sunshine in May: 10h and 2min

The months with the most sunshine are July and August (Average sunshine: 11h and 42min).
The months with the least sunshine are January and December (Average sunshine: 5h and 24min).

Average sunshine days in May
Grantsdale, MT

Average sunshine days in May - Grantsdale, MT
  • Average sunshine days in May: 8.5 days

The month with the most sunshine days is July (18.9 days).
The month with the least sunshine days is February (5.6 days).

Average UV index in May
Grantsdale, MT

Average UV index in May - Grantsdale, MT
  • Average UV index in May: 4

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are February and December (UV index 1).

Average cloud cover in May
Grantsdale, MT

Average cloud cover in May - Grantsdale, MT
  • Average cloud cover in May: 33

The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 13).

Average visibility in May
Grantsdale, MT

Average visibility in May - Grantsdale, MT
  • Average visibility in May: 6mi

The months with the highest visibility are May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March and December (4mi).

Grantsdale, Montana, USA

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