September weather forecastArlington, MA
September
Weather in September
September in Arlington, Massachusetts signals the start of the fall season with a noticeable drop in temperatures from August. The cooling trend is carried from August, with September ushering in the richness of the autumn season. Highlighting September's weather transition, this month records the least amount of rainfall with just 1.3" (33mm). The arrival of October presents a continuation of diminishing temperatures. The spectacle of changing leaf colors throughout September provides a picturesque backdrop to the natural landscapes.Temperature
With the arrival of September, Arlington experiences a modest decline in average high-temperatures, transitioning from a warm 80.8°F (27.1°C) in August to an agreeable 73°F (22.8°C). In the month of September, an average of 56.5°F (13.6°C) marks the low-temperature.Humidity
In Arlington, the average relative humidity in September is 75%.Rainfall
September is the month with the least rainfall. Rain falls for 10.7 days and accumulates 1.3" (33mm) of precipitation.Snowfall
June through September are months without snowfall in Arlington.Daylight
In September, the average length of the day is 12h and 29min.On the first day of September, sunrise is at 6:10 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:27 pm EDT.
Sunshine
The average sunshine in September is 8.5h.UV index
The average daily maximum UV index in September in Arlington is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for average individuals.Note: The UV index of 4 in September translates into these instructions:
Be vigilant - A duty to shield skin and eyes from injury exists. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Arlington, MA
- Average high temperature in September: 73°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (33.4°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (21.7°F).
Average pressure in September
Arlington, MA
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Arlington, MA
- Average wind speed in September: 6.5mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest month (with the lowest average wind speed) is August (5.9mph).
Average humidity in September
Arlington, MA
- Average humidity in September: 75%
The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (70%).
Average rainfall in September
Arlington, MA
- Average rainfall in September: 1.3"
The wettest month (with the highest rainfall) is December (2.95").
The driest month (with the least rainfall) is September (1.3").
Average rainfall days in September
Arlington, MA
- Average rainfall days in September: 10.7 days
The months with the highest number of rainy days are May and July (15.3 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in September
Arlington, MA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Arlington, MA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Arlington, MA
- Average daylight in September: 12h and 30min
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 6min).
- Average sunshine in September: 8h and 30min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in September
Arlington, MA
- Average sunshine days in September: 17.4 days
The month with the most sunshine days is November (17.6 days).
The month with the least sunshine days is April (13.3 days).
Average UV index in September
Arlington, MA
- Average UV index in September: 4
The months with the highest UV index are June, 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
Arlington, MA
- Average cloud cover in September: 36
The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Arlington, MA
- Average visibility in September: 6mi
The months with the highest visibility are January, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is February (5mi).
