May weather forecast and climate
Grantsdale, MT

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

Temperature

In Grantsdale, the average high-temperature rises, from a chilly 43.5°F (6.4°C) in April, to a mild 56.7°F (13.7°C). In May, in Grantsdale, the average low-temperature is 33.4°F (0.8°C).

Humidity

In May, the average relative humidity is 71%.

Rainfall

In Grantsdale, 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, in Grantsdale, there are 101.1 snowfall days, and 59.17" (1503mm) of snow is accumulated.

Daylight

In May, the average length of the day in Grantsdale is 15h.

Sunshine

The average sunshine is 10.4h.

UV index

In May, the average daily maximum UV index in Grantsdale is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.

What is the temperature in May in Grantsdale?

The average high-temperature, in May, 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 in Grantsdale?

In Grantsdale, the average relative humidity in May is 71%.

How many days does it rain in May in Grantsdale?

In Grantsdale, Montana, in May, it is raining for 19.5 days, with typically 1.97" (50mm) of accumulated precipitation.

What is the last month it snows in Grantsdale?

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

What is the average length of the day in May in Grantsdale?

In Grantsdale, Montana, the average length of the day in May is 15h.

How long on average sun shines in May in Grantsdale?

In Grantsdale, the average sunshine in May is 10.4h.

How high is the UV index in May in Grantsdale?

In May, the average daily maximum UV index in Grantsdale is 4. A UV Index estimate of 3 to 5 represents a medium health risk from the exposure to the Sun's UV radiation.
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: 29.96"

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

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: 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: 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: 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: 0.67"

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

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).
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: 15h

The month with the longest days is June (Average daylight: 15.7h).
The month with the shortest days is December (Average daylight: 8.7h).

  • Average sunshine in May: 10.4h

Months with the most sunshine are July and August (Average sunshine: 11.7h).
Months with the least sunshine are January and December (Average sunshine: 5.4).

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: 4

The month with the highest UV index is July (UV index 5).
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: 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: 6mi

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