August weather forecast
Boulder, MT

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Weather in August

The last month of the summer, August, is another warm month in Boulder, Montana, with an average temperature fluctuating between 48.6°F (9.2°C) and 77.5°F (25.3°C).

Temperature

As Boulder, Montana, steps into August, the average high-temperature holds at a still moderately hot 77.5°F (25.3°C), hinting at a minor fluctuation from the prior month. August nights in Boulder bring a significant cooling from the heat of the day, with averages of 48.6°F (9.2°C).

Humidity

The least humid month in Boulder is August, with an average relative humidity of 46%.

Rainfall

In August, the rain falls for 9.8 days. Throughout August, 0.91" (23mm) of precipitation is accumulated. In Boulder, during the entire year, the rain falls for 133.7 days and collects up to 16.38" (416mm) of precipitation.

Snowfall

July and August are months without snowfall in Boulder.

Daylight

In Boulder, the average length of the day in August is 14h and 6min.
On the first day of the month, sunrise is at 6:11 am and sunset at 8:58 pm. On the last day of August, sunrise is at 6:48 am and sunset at 8:08 pm MDT.

Sunshine

The average sunshine in August in Boulder is 11.5h.

UV index

In Boulder, the average daily maximum UV index in August is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.
Note: The maximum UV index of 4 during August leads to these instructions:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.
Updated: Feb 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Boulder in August?

Boulder in August has an average high-temperature of 77.5°F (25.3°C) and an average low-temperature of 48.6°F (9.2°C).

What is the least humid month in Boulder?

The least humid month in Boulder, Montana, is August, with an average relative humidity of 46%.

What is the average humidity in August in Boulder?

In August, the average relative humidity in Boulder, Montana, is 46%.

How much does it rain in Boulder in August?

In August, the rain falls for 9.8 days. Throughout August, 0.91" (23mm) of precipitation is accumulated.

When it does not snow in Boulder?

July and August are months without snowfall in Boulder, Montana.

Does it snow in Boulder in August?

In Boulder, Montana, in August, it doesn't snow. In September, it regularly snows.

What is the average length of the day in August in Boulder?

In August, the average day length in Boulder, Montana, is 14h and 6min.

What time are sunrise and sunset in August in Boulder?

In August, on the first day of the month, sunrise is at 6:11 am and sunset at 8:58 pm. On the last day of the month, in Boulder, Montana, sunrise is at 6:48 am and sunset at 8:08 pm MDT.

How long on average sun shines in August in Boulder?

The average sunshine duration in August in Boulder, Montana, is 11.5h.

How high is the UV index in August in Boulder?

The average daily maximum UV index in August 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
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Boulder, MT

Average temperature in August - Boulder, MT
  • Average high temperature in August: 77.5°F

The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (27°F).

  • Average low temperature in August: 48.6°F

The month with the highest average low temperature is August (48.6°F).
The coldest month (with the lowest average low temperature) is December (12.6°F).

Average pressure in August
Boulder, MT

Average pressure in August - Boulder, MT
  • Average pressure in August: 29.96"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in August
Boulder, MT

Average wind speed in August - Boulder, MT
  • Average wind speed in August: 4.7mph

The windiest months (with the highest average wind speed) are January and November (6.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).

Average humidity in August
Boulder, MT

Average humidity in August - Boulder, MT
  • Average humidity in August: 46%

The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is August (46%).

Average rainfall in August
Boulder, MT

Average rainfall in August - Boulder, MT
  • Average rainfall in August: 0.91"

The wettest month (with the highest rainfall) is June (2.68").
The driest month (with the least rainfall) is December (0.79").

Average rainfall days in August
Boulder, MT

Average rainfall days in August - Boulder, MT
  • Average rainfall days in August: 9.8 days

The month with the highest number of rainy days is May (18.2 days).
The month with the least rainy days is November (7.5 days).

Average snowfall in August
Boulder, MT

Average snowfall in August - Boulder, MT
  • Average snowfall in August: 0"

The month with the highest snowfall is February (9.72").
The months with the least snowfall are July and August (0").

Average snowfall days in August
Boulder, MT

Average snowfall days in August - Boulder, MT
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is February (18 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in August /
Average sunshine in August
Boulder, MT

Average daylight in August / Average sunshine in August - Boulder, MT
  • Average daylight in August: 14h and 1min

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 August: 11h and 3min

The month with the most sunshine is July (Average sunshine: 11h and 42min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).

Average sunshine days in August
Boulder, MT

Average sunshine days in August - Boulder, MT
  • Average sunshine days in August: 17 days

The month with the most sunshine days is September (17.9 days).
The month with the least sunshine days is February (8.5 days).

Average UV index in August
Boulder, MT

Average UV index in August - Boulder, MT
  • Average UV index in August: 4

The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).

Average cloud cover in August
Boulder, MT

Average cloud cover in August - Boulder, MT
  • Average cloud cover in August: 15

The month with the most cloud cover is February (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 15).

Average visibility in August
Boulder, MT

Average visibility in August - Boulder, MT
  • Average visibility in August: 6mi

The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).

Boulder, Montana, USA

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