Barnstable County (Hyannis)
September
Weather in Barnstable County, Massachusetts for September 2026
Your guide to Barnstable County weather in September - trends and predictions
So far, September 2026 in Barnstable County is slightly warmer than the historical average by 1.1 °F.
Expect cooler weather in the next days in Barnstable County with the forecast suggesting a temperature of 19.7 °F, lower than the historical average.
In general, the average temperature in Barnstable County at the beginning of September is 22.3 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 20.7 °F by the end of September.
Barnstable County experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 56.1 mm.
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Temperatures
Rain 🌧️
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24
Dry days
6
Rainy days
0
Snow days
20°/16°
Temperatures
21 km/h
Avg max wind
83 %
Avg humidity
Barnstable County Weather September
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Temperatures trend during September in Barnstable County
See the weather trend as well as the moving average line
September weather in Barnstable County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Partly cloudy | 22° /16° | 95.4 mm | 5 | |
| Sept. 2 | Partly cloudy | 22° /15° | 0 mm | 6 | |
| Sept. 3 |  Fog | 22° /15° | 159.6 mm | 2 | |
| Sept. 4 | Mist | 23° /17° | 0 mm | 4 | |
| Sept. 5 |  Overcast | 22° /16° | 0 mm | 4 | |
| Sept. 6 | Overcast | 22° /17° | 10.9 mm | 2 | |
| Sept. 7 |  Moderate rain at times | 23° /14° | 3.4 mm | 4 | |
| Sept. 8 | Overcast | 23° /14° | 0 mm | 6 | |
| Sept. 9 | Partly cloudy | 23° /16° | 0.3 mm | 4 | |
| Sept. 10 | Overcast | 23° /19° | 0 mm | 1 | |
| Sept. 11 | Overcast | 24° /16° | 0 mm | 6 | |
| Sept. 12 |  Cloudy | 22° /14° | 0 mm | 7 | |
| Sept. 13 |  Sunny | 21° /16° | 25.6 mm | 4 | |
| Sept. 14 | Overcast | 21° /17° | 0.8 mm | 5 | |
| Sept. 15 | Fog | 18° /14° | 0 mm | 4 | |
| Sept. 16 | Fog | 18° /13° | 0 mm | 3 | |
| Sept. 17 | Sunny | 24° /18° | 0 mm | 6 | |
| Sept. 18 | Overcast | 21° /19° | 2.1 mm | 6 | |
| Sept. 19 | Overcast | 18° /13° | 0 mm | 4 | |
| Sept. 20 |  Light rain shower | 20° /12° | 14.4 mm | 4 | |
| Sept. 21 | Patchy rain possible | 16° /14° | 0.2 mm | 5 | |
| Sept. 22 | Overcast | 16° /13° | 1.8 mm | 4 | |
| Sept. 23 | Light rain shower | 16° /13° | 36.8 mm | 4 | |
| Sept. 24 | Patchy rain possible | 21° /16° | 0.9 mm | 5 | |
| Sept. 25 | Sunny | 21° /14° | 0.6 mm | 6 | |
| Sept. 26 | Sunny | 16° /11° | 0 mm | 5 | |
| Sept. 27 | Sunny | 18° /10° | 0 mm | 5 | |
| Sept. 28 | Sunny | 22° /14° | 0 mm | 6 | |
| Sept. 29 | Overcast | 24° /17° | 0 mm | 6 | |
| Sept. 30 | Overcast | 23° /17° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Barnstable County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Barnstable County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Barnstable County in September - FAQ
What are the expected maximum and minimum temperatures in Barnstable County during September?
During September, expect a variety of temperatures with highs around 20° and lows near 16°, suitable for diverse activities and preferences.
How much rainfall should be expected in Barnstable County during September?
Moderate rainfall is anticipated in Barnstable County during September, with a total of 56.1 mm spread over approximately 6 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Barnstable County during September?
The average wind speed in Barnstable County during September is 21 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Barnstable County
Explore the daily rainfall trends and prepare for Barnstable Countys September weather 💧
Typically, Barnstable County has 6 rainy days in September with a total of 56.1 mm of rainfall.
UV exposure in Barnstable County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Barnstable County?Get accurate weather forecasts for Barnstable County, located at latitude 41.653 and longitude -70.283. Stay updated with localized weather information tailored for Barnstable County.
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