May weather forecast
Roy, MT

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Weather in May

May, the last month of the spring in Roy, is a mild month, with an average temperature ranging between max 58.5°F (14.7°C) and min 40.1°F (4.5°C).

Temperature

May's arrival coincides with a rise in the average high-temperature, moving from April's frosty 47.8°F (8.8°C) to a refreshing 58.5°F (14.7°C). An average low-temperature of 40.1°F (4.5°C) is recorded during the nights in May in Roy, Montana.

Humidity

In Roy, the average relative humidity in May is 65%.

Rainfall

The month with the most rainfall is May, when the rain falls for 19.3 days and typically aggregates up to 3.39" (86mm) of precipitation.

Snowfall

January through June, September through December are months with snowfall in Roy. In Roy, in May, snow falls for 2.4 days, with typically accumulated 2.48" (63mm) of snow. Throughout the year, there are 83.4 snowfall days, and 45.51" (1156mm) of snow is accumulated.

Daylight

In May, the average length of the day in Roy is 15h and 8min.
On the first day of May in Roy, sunrise is at 5:57 am and sunset at 8:27 pm. On the last day of the month, sunrise is at 5:23 am and sunset at 9:04 pm MDT.

Sunshine

In Roy, the average sunshine in May is 10h.

UV index

In Roy, the average daily maximum UV index in May is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: In May, a daily maximum UV index of 4 leads to the following instructions:
Act with care - Obligation to protect against skin and eye damage is highlighted. It's recommended to limit sun exposure when its radiation is at its peak during midday. During bright days, sunglasses that offer UVA and UVB defense are recommended. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average May temperature in Roy?

In May, in Roy, the average high-temperature is 58.5°F (14.7°C), and the average low-temperature is 40.1°F (4.5°C).

What is the average humidity in May in Roy?

In May, the average relative humidity in Roy, Montana, is 65%.

What is the rainiest month in Roy?

May is the month with the most rainfall in Roy. Rain falls for 19.3 days and accumulates 3.39" (86mm) of precipitation.

How many days does it rain in May in Roy?

In Roy, Montana, during May, the rain falls for 19.3 days and regularly aggregates up to 3.39" (86mm) of precipitation.

How many days does it snow in May in Roy?

In Roy, Montana, during May, snow falls for 2.4 days and regularly aggregates up to 2.48" (63mm) of snow.

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

The average day length in May is 15h and 8min.

What time are sunrise and sunset in May in Roy?

In May, on the first day of the month, sunrise is at 5:57 am and sunset at 8:27 pm. On the last day of the month, sunrise is at 5:23 am and sunset at 9:04 pm MDT.

How many hours of sunshine does Roy have in May?

In May, the average sunshine duration in Roy, Montana, is 10h.

How high is the UV index in May in Roy?

The average daily maximum UV index in May is 4. A UV Index value of 3 to 5 symbolizes a moderate health threat from unprotected exposure to UV radiation.
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
Roy, MT

Average temperature in May - Roy, MT
  • Average high temperature in May: 58.5°F

The warmest month (with the highest average high temperature) is July (78.8°F).
The months with the lowest average high temperature are February and December (29.1°F).

  • Average low temperature in May: 40.1°F

The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is February (15.3°F).

Average pressure in May
Roy, MT

Average pressure in May - Roy, MT
  • Average pressure in May: 29.92"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
Roy, MT

Average wind speed in May - Roy, MT
  • Average wind speed in May: 8.8mph

The windiest months (with the highest average wind speed) are January, April and October (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.4mph).

Average humidity in May
Roy, MT

Average humidity in May - Roy, MT
  • Average humidity in May: 65%

The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is August (47%).

Average rainfall in May
Roy, MT

Average rainfall in May - Roy, MT
  • Average rainfall in May: 3.39"

The wettest month (with the highest rainfall) is May (3.39").
The driest month (with the least rainfall) is December (0.71").

Average rainfall days in May
Roy, MT

Average rainfall days in May - Roy, MT
  • Average rainfall days in May: 19.3 days

The month with the highest number of rainy days is May (19.3 days).
The month with the least rainy days is January (5.4 days).

Average snowfall in May
Roy, MT

Average snowfall in May - Roy, MT
  • Average snowfall in May: 2.48"

The month with the highest snowfall is April (9.13").
The months with the least snowfall are July and August (0").

Average snowfall days in May
Roy, MT

Average snowfall days in May - Roy, MT
  • Average snowfall days in May: 2.4 days

The month with the highest number of snowfall days is February (15.2 days).
The months with the least snowfall days are July and August (0 days).

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

Average daylight in May / Average sunshine in May - Roy, MT
  • Average daylight in May: 15h and 1min

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in May: 10h and 0min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 30min).

Average sunshine days in May
Roy, MT

Average sunshine days in May - Roy, MT
  • Average sunshine days in May: 8.9 days

The month with the most sunshine days is September (19.3 days).
The month with the least sunshine days is April (8.3 days).

Average UV index in May
Roy, MT

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

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

Average cloud cover in May
Roy, MT

Average cloud cover in May - Roy, MT
  • Average cloud cover in May: 36

The month with the most cloud cover is February (Cloud cover 45).
The month with the least cloud cover is July (Cloud cover 16).

Average visibility in May
Roy, MT

Average visibility in May - Roy, 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).

Roy, Montana, USA

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