Great Falls
Montana, USA
Long-term weather forecast
Long-term weather forecast

May weather forecast and climate
Great Falls, MT

A far view from on top of the vast Missouri River of the City of Lights, Great Falls, Montana, a dusk sky, mirror images in the water
A far view from on top of the vast Missouri River of the City of Lights, Great Falls, Montana, a dusk sky, mirror images in the water
May, the last month of the spring, in Great Falls, is a comfortable month, with temperature in the range of an average low of 38.7°F (3.7°C) and an average high of 64.8°F (18.2°C).

Temperature

In May, the average high-temperature rises, from a mild 55.6°F (13.1°C) in April, to a comfortable 64.8°F (18.2°C). In Great Falls, the average low-temperature is 38.7°F (3.7°C).

Rainfall

In Great Falls, it is raining for 11.7 days, with typically 2.4" (61.5mm) of accumulated precipitation. In Great Falls, during the entire year, the rain falls for 99.9 days and collects up to 14.8" (374.8mm) of precipitation.

Snowfall

Months with snowfall in Great Falls are January through June, August through December.

Daylight

In May, the average length of the day in Great Falls, Montana, is 15.1h.

Sunshine

In May, the average sunshine in Great Falls, Montana, is 9.2h.

UV index

In Great Falls, the average daily maximum UV index is 6. A UV Index reading of 6 to 7 represents a high health risk from the exposure to the Sun's UV rays for the average person.
In May, the average maximum UV index of 6 translate into the following recommendations:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. 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 Great Falls?

In Great Falls, Montana, in May, the average high-temperature is 64.8°F (18.2°C), and the average low-temperature is 38.7°F (3.7°C).

How many days does it rain in May in Great Falls?

In May, in Great Falls, the rain falls for 11.7 days. Throughout May, 2.4" (61.5mm) of precipitation is accumulated.

How much does it snow in Great Falls in May?

In May, in Great Falls, it is snowing for 1.6 days. Throughout May, 2.7" (68.6mm) of snow is accumulated.

What is the average length of the day in May in Great Falls?

In May, the average length of the day in Great Falls is 15.1h.

How long on average sun shines in May in Great Falls?

The average sunshine in May in Great Falls, Montana, is 9.2h.

What is the UV index intensity in May in Great Falls?

In Great Falls, Montana, the average daily maximum UV index in May is 6. A UV Index estimate of 6 to 7 represents a high health threat from unprotected exposure to the UV radiation.
Average temperature in May - Great Falls, MT
  • Average high temperature in May: 64.8°F

The warmest month (with the highest average high temperature) is July (83.4°F).
The month with the lowest average high temperature is December (34.6°F).

  • Average low temperature in May: 38.6°F

The month with the highest average low temperature is July (51.4°F).
Coldest months (with the lowest average low temperature) are January and December (14.9°F).

Average rainfall in May - Great Falls, MT
  • Average rainfall in May: 2.4"

The wettest month (with the highest rainfall) is June (2.5").
Driest months (with the lowest rainfall) are January and February (0.5").

Average rainfall days in May - Great Falls, MT
  • Average rainfall days in May: 11.7 days

Months with the highest number of rainy days are May and June (11.7 days).
The month with the lowest number of rainy days is October (6.6 days).

Average snowfall in May - Great Falls, MT
  • Average snowfall in May: 2.7"

The month with the highest snowfall is March (11.9").
The month with the lowest snowfall is July (0").

Average snowfall days in May - Great Falls, MT
  • Average snowfall days in May: 1.6 days

The month with the highest number of snowfall days is March (7.8 days).
The month with the lowest number of snowfall days is July (0 days).

Average daylight in May / Average sunshine in May - Great Falls, MT
  • Average daylight in May: 15.1h

The month with the longest days is June (Average daylight: 15.9h).
The month with shortest days is December (Average daylight: 8.5h).

  • Average sunshine in May: 9.2h

The month with most sunshine is July (Average sunshine: 12.2h).
The month with least sunshine is December (Average sunshine: 3.4h).

Average UV index in May - Great Falls, MT
  • Average UV index in May: 6

Months with the highest UV index are June and July (UV index 8).
Months with the lowest UV index are January, November and December (UV index 1).