August weather forecastBoulder, CO
August
Weather in August
In Boulder, August is the last full summer month, characterized by sustained warmth and decreasing rainfall. Though it mirrors much of July's warmth, a slight dip in temperature indicates the upcoming autumn. The wind velocity typically averages around 5.7mph (9.2km/h) in August, ushering in cooler evenings. September will see a further decrease in temperature, and the advent of the year's cooler half. Hence, August is the perfect month soaking up last bits of summer before autumn sets in.Temperature
August's weather records an average high-temperature of a still warm 79.5°F (26.4°C), showing little deviation from July. Despite substantial daily fluctuations, the average low-temperature is a fresh 54.1°F (12.3°C) during August.Humidity
June, August and September, with an average relative humidity of 45%, are the least humid months.Rainfall
In Boulder, in August, it is raining for 14.6 days, with typically 1.26" (32mm) of accumulated precipitation. In Boulder, during the entire year, the rain falls for 117.3 days and collects up to 14.17" (360mm) of precipitation.Snowfall
In Boulder, snow does not fall in June through September.Daylight
The average length of the day in August is 13h and 42min.On the first day of the month, sunrise is at 6:00 am and sunset at 8:14 pm. On the last day of August, sunrise is at 6:28 am and sunset at 7:33 pm MDT.
Sunshine
In Boulder, the average sunshine in August is 11.6h.UV index
The months with the highest UV index are June through August, with an average maximum UV index of 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum UV index of 5 during August leads to these instructions:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Boulder, CO
- Average high temperature in August: 79.5°F
The warmest month (with the highest average high temperature) is July (80.4°F).
The month with the lowest average high temperature is December (35.2°F).
- Average low temperature in August: 54.1°F
The month with the highest average low temperature is July (55.2°F).
The coldest month (with the lowest average low temperature) is February (18°F).
Average pressure in August
Boulder, CO
- Average pressure in August: 30.01"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are April, May and June (29.92"Hg).
Average wind speed in August
Boulder, CO
- Average wind speed in August: 5.7mph
The windiest month (with the highest average wind speed) is January (7.3mph).
The calmest months (with the lowest average wind speed) are May, July, August and September (5.7mph).
Average humidity in August
Boulder, CO
- Average humidity in August: 45%
The month with the highest relative humidity is February (70%).
The months with the lowest relative humidity are June, August and September (45%).
Average rainfall in August
Boulder, CO
- Average rainfall in August: 1.26"
The wettest month (with the highest rainfall) is May (2.48").
The driest month (with the least rainfall) is January (0.39").
Average rainfall days in August
Boulder, CO
- Average rainfall days in August: 14.6 days
The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is November (3.3 days).
Average snowfall in August
Boulder, CO
- Average snowfall in August: 0"
The month with the highest snowfall is April (7.76").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in August
Boulder, CO
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is February (10.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in August /
Average sunshine in August
Boulder, CO
- Average daylight in August: 13h and 42min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in August: 11h and 36min
The months with the most sunshine are June and July (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 6h and 36min).
Average sunshine days in August
Boulder, CO
- Average sunshine days in August: 12.4 days
The month with the most sunshine days is January (22.2 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in August
Boulder, CO
- Average UV index in August: 5
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in August
Boulder, CO
- Average cloud cover in August: 18
The months with the most cloud cover are April and May (Cloud cover 28).
The month with the least cloud cover is September (Cloud cover 16).
Average visibility in August
Boulder, CO
- Average visibility in August: 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).
