August weather forecastHyannis, MA
August
Weather in August
August in Hyannis displays a continuation of summer climate, with conditions relatively similar to those of July. Despite a slightly higher land temperature, the sea temperature remains steady at 67.5°F (19.7°C). With a dip in rainfall accompanied by longer sunshine hours, the city's weather maintains summer characteristics. Variations in weather aspects are minimal between July and August. Moderate wind speeds offer a pleasant breeze against the high temperatures, adding to the enjoyment of outdoor activities.Temperature
Hyannis's August weather reaches an average high of 72.5°F (22.5°C) and an average low of 68.2°F (20.1°C), making it the warmest month.Humidity
In Hyannis, Massachusetts, the average relative humidity in August is 81%.Rainfall
August is the month with the least rainfall. Rain falls for 12.4 days and accumulates 1.73" (44mm) of precipitation.Snowfall
May through November are months without snowfall.Ocean temperature
With an average ocean temperature of 67.5°F (19.7°C), August is the month with the warmest seawater.Note: A majority do not enjoy swimming in water at 67.5°F (19.7°C). The difficulty in controlling breathing increases progressively as the temperature dips below 69.8°F (21°C).
Daylight
In August, the average length of the day is 13h and 48min.On the first day of August, sunrise is at 5:36 am and sunset at 7:58 pm. On the last day of the month, sunrise is at 6:06 am and sunset at 7:15 pm EDT.
Sunshine
August has the most sunshine of the year, with an average of 10.8h of sunshine.UV index
The months with the highest UV index are July and August, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for the average person.Note: In August, the UV index of 6 transforms into the following advice:
Avert overexposure. Light-skinned people might experience burning in less than 20 minutes. Avoid exposure to the Sun and try to stay in the shade between 10 a.m. and 4 p.m., when UV radiation is most potent, but be aware that parasols or canopies may not offer full protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Hyannis, MA
- Average high temperature in August: 72.5°F
The warmest month (with the highest average high temperature) is August (72.5°F).
The month with the lowest average high temperature is January (38.3°F).
- Average low temperature in August: 68.2°F
The month with the highest average low temperature is August (68.2°F).
The coldest month (with the lowest average low temperature) is January (30.4°F).
Average pressure in August
Hyannis, MA
- Average pressure in August: 29.98"Hg
The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in August
Hyannis, MA
- Average wind speed in August: 10.6mph
The windiest month (with the highest average wind speed) is January (16.5mph).
The calmest month (with the lowest average wind speed) is August (10.6mph).
Average humidity in August
Hyannis, MA
- Average humidity in August: 81%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is November (74%).
Average rainfall in August
Hyannis, MA
- Average rainfall in August: 1.73"
The wettest month (with the highest rainfall) is October (3.7").
The driest month (with the least rainfall) is August (1.73").
Average rainfall days in August
Hyannis, MA
- Average rainfall days in August: 12.4 days
The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is February (10.3 days).
Average snowfall in August
Hyannis, MA
- Average snowfall in August: 0"
The month with the highest snowfall is March (1.93").
The months with the least snowfall are May, June, July, August, September, October and November (0").
Average snowfall days in August
Hyannis, MA
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is February (7.1 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in August
Hyannis, MA
- Average sea temperature in August: 67.5°F
The best month for swimming (with the highest average sea temperature) is August (67.5°F).
The coldest month (with the lowest average sea temperature) is March (39°F).
Average daylight in August /
Average sunshine in August
Hyannis, MA
- Average daylight in August: 13h and 48min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in August: 10h and 48min
The month with the most sunshine is August (Average sunshine: 10h and 48min).
The month with the least sunshine is December (Average sunshine: 4h and 36min).
Average sunshine days in August
Hyannis, MA
- Average sunshine days in August: 17.7 days
The month with the most sunshine days is August (17.7 days).
The month with the least sunshine days is February (11.4 days).
Average UV index in August
Hyannis, MA
- Average UV index in August: 6
The months with the highest UV index are July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in August
Hyannis, MA
- Average cloud cover in August: 27
The months with the most cloud cover are February and December (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in August
Hyannis, MA
- 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).





