May weather forecast
Lewistown, MT

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Weather in May

May signifies a period of increased weather activity with the transition of seasons. With temperatures ascending to 58.5°F (14.7°C), indicating a significant departure from April, the warmth becomes noticeable. A peak rainfall volume of 3.39" (86mm) documents the heaviest downpour for the year. Longer daylight hours coupled with more sunshine manifest the imminent arrival of summer. Following April’s trend, the city witnesses a further decrease of relative humidity.

Temperature

Lewistown sees a rise in temperature during May, with average high-temperatures transitioning from a chilly 47.8°F (8.8°C) in April to a mild 58.5°F (14.7°C). Nighttime temperatures consistently average a cold 40.1°F (4.5°C) during May.

Humidity

In May, the average relative humidity 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 May, in Lewistown, it is snowing for 2.4 days. Throughout May, 2.48" (63mm) of snow is accumulated. In Lewistown, during the entire year, snow falls for 83.4 days and aggregates up to 45.51" (1156mm) of snow.

Daylight

In May, the average length of the day in Lewistown is 15h and 6min.
On the first day of the month, sunrise is at 6:00 am and sunset at 8:29 pm. On the last day of May, sunrise is at 5:26 am and sunset at 9:04 pm MDT.

Sunshine

The average sunshine in May in Lewistown is 10h.

UV index

The average daily maximum UV index in May is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: In May, a regular UV index of 4 translates into these guidelines:
Take precautions - Protection against sunburn is recommended. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Watch out! The Sun's UV radiation can be nearly magnified twofold due to snow reflection.
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Frequently asked questions

What is the usual temperature for Lewistown in May?

In May, the average high-temperature and low-temperature in Lewistown, Montana, are 58.5°F (14.7°C) and 40.1°F (4.5°C) respectively.

What is the average humidity in May in Lewistown?

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

What is the rainiest month in Lewistown?

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

How much does it rain in Lewistown in May?

In May, the rain falls for 19.3 days. Throughout May, 3.39" (86mm) of precipitation is accumulated.

How many days does it snow in May in Lewistown?

In Lewistown, Montana, in May, snow falls for 2.4 days, with typically accumulated 2.48" (63mm) of snow.

How many hours of daylight does Lewistown have in May?

In Lewistown, the average day length in May is 15h and 6min.

What time are sunrise and sunset in May in Lewistown?

On the first day of May in Lewistown, sunrise is at 6:00 am and sunset at 8:29 pm. On the last day of the month, sunrise is at 5:26 am and sunset at 9:04 pm MDT.

How many hours of sunshine does Lewistown have in May?

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

How high is the UV index in May in Lewistown?

The average daily maximum UV index in May is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unsafe 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
Lewistown, MT

Average temperature in May - Lewistown, 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).

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Average pressure in May
Lewistown, MT

Average pressure in May - Lewistown, 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).

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Average wind speed in May
Lewistown, MT

Average wind speed in May - Lewistown, 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).

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Average humidity in May
Lewistown, MT

Average humidity in May - Lewistown, 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%).

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Average rainfall in May
Lewistown, MT

Average rainfall in May - Lewistown, 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").

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Average rainfall days in May
Lewistown, MT

Average rainfall days in May - Lewistown, 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).

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Average snowfall in May
Lewistown, MT

Average snowfall in May - Lewistown, 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").

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Average snowfall days in May
Lewistown, MT

Average snowfall days in May - Lewistown, 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).

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

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

The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).

  • 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).

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Average sunshine days in May
Lewistown, MT

Average sunshine days in May - Lewistown, 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).

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Average UV index in May
Lewistown, MT

Average UV index in May - Lewistown, 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).

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Average cloud cover in May
Lewistown, MT

Average cloud cover in May - Lewistown, 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).

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Average visibility in May
Lewistown, MT

Average visibility in May - Lewistown, 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).

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Lewistown, Montana, USA

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