Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The advent of September in Chatham, Massachusetts, denotes an average high-temperature of a refreshing 66.6°F (19.2°C), subtly different from August's 71.6°F (22°C). Chatham, during September nights, witnesses an average temperature marginally cooler than its daytime highs, at a still enjoyable 63.3°F (17.4°C).Humidity
The average relative humidity in September in Chatham, Massachusetts, is 80%.Rainfall
In Chatham, Massachusetts, in September, during 10.7 rainfall days, 1.85" (47mm) of precipitation is typically accumulated. In Chatham, during the entire year, the rain falls for 142.4 days and collects up to 22.09" (561mm) of precipitation.Snowfall
May through October are months without snowfall.Ocean temperature
In Chatham, in September, the average water temperature is 63.9°F (17.7°C).Note: Most people find swimming in 63.9°F (17.7°C) to be not enjoyable. The control of one's breathing becomes more challenging as the water temperature drops below 69.8°F (21°C).
Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:06 am and sunset at 7:12 pm. On the last day of September, sunrise is at 6:36 am and sunset at 6:22 pm EDT.
Sunshine
In Chatham, the average sunshine in September is 8.5h.UV index
In September, the average daily maximum UV index in Chatham is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for average individuals.Note: A maximum high daily UV index of 4 during September translates into the following directions:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Frequently asked questions
What are the temperatures in Chatham in September?
What is the average humidity in September in Chatham?
How many days does it rain in September in Chatham?
When it does not snow in Chatham?
How cold is the water in September in Chatham?
What is the average length of the day in September in Chatham?
What time are sunrise and sunset in September in Chatham?
How many hours of sunshine does Chatham have in September?
What is the UV index reading in September in Chatham?
Average temperature in September
Chatham, MA
- Average high temperature in September: 66.6°F
The warmest month (with the highest average high temperature) is August (71.6°F).
The months with the lowest average high temperature are January and February (39°F).
- Average low temperature in September: 63.3°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 (31.6°F).
Average pressure in September
Chatham, MA
- Average pressure in September: 30.05"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 September
Chatham, MA
- Average wind speed in September: 13.5mph
The windiest month (with the highest average wind speed) is January (18mph).
The calmest month (with the lowest average wind speed) is August (11.4mph).
Average humidity in September
Chatham, MA
- Average humidity in September: 80%
The months with the highest relative humidity are June and July (85%).
The month with the lowest relative humidity is November (74%).
Average rainfall in September
Chatham, MA
- Average rainfall in September: 1.85"
The wettest month (with the highest rainfall) is October (2.83").
The driest month (with the least rainfall) is November (1.46").
Average rainfall days in September
Chatham, MA
- Average rainfall days in September: 10.7 days
The month with the highest number of rainy days is May (14.6 days).
The month with the least rainy days is February (8.3 days).
Average snowfall in September
Chatham, MA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.38").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Chatham, MA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Chatham, MA
- Average sea temperature in September: 63.8°F
The best month for swimming (with the highest average sea temperature) is August (67.6°F).
The coldest month (with the lowest average sea temperature) is March (39.8°F).
Average daylight in September /
Average sunshine in September
Chatham, MA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 8h and 3min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 18min).
Average sunshine days in September
Chatham, MA
- Average sunshine days in September: 16.9 days
The month with the most sunshine days is August (17.6 days).
The month with the least sunshine days is January (13 days).
Average UV index in September
Chatham, MA
- Average UV index in September: 4
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 September
Chatham, MA
- Average cloud cover in September: 32
The month with the most cloud cover is December (Cloud cover 54).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Chatham, MA
- Average visibility in September: 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).
Chatham, Massachusetts, USA
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