Merrimack County (Concord)
September
Weather in Merrimack County, New Hampshire for September 2026
Your guide to Merrimack County weather in September - trends and predictions
So far, September 2026 in Merrimack County is slightly warmer than the historical average by 0.6 °F.
The forecast for the next days in Merrimack County predicts a temperature of 18.6 °F, which is cooler than the historical average.
In general, the average temperature in Merrimack County at the beginning of September is 23.4 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 19.9 °F by the end of September.
Merrimack County experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 302 mm.
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Temperatures
Rain 🌧️
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24
Dry days
6
Rainy days
0
Snow days
22°/11°
Temperatures
12 km/h
Avg max wind
73 %
Avg humidity
Merrimack County Weather September
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Temperatures trend during September in Merrimack County
See the weather trend as well as the moving average line
September weather in Merrimack County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Overcast | 21° /13° | 89.8 mm | 4 | |
| Sept. 2 |  Fog | 22° /14° | 0.1 mm | 3 | |
| Sept. 3 | Fog | 25° /13° | 75.4 mm | 4 | |
| Sept. 4 | Mist | 26° /12° | 0 mm | 6 | |
| Sept. 5 |  Moderate rain | 24° /14° | 12.1 mm | 5 | |
| Sept. 6 |  Moderate rain at times | 25° /15° | 5.5 mm | 3 | |
| Sept. 7 | Moderate rain | 21° /9° | 26.4 mm | 4 | |
| Sept. 8 | Mist | 24° /10° | 0 mm | 6 | |
| Sept. 9 |  Sunny | 23° /9° | 3.6 mm | 4 | |
| Sept. 10 | Mist | 25° /13° | 9.7 mm | 5 | |
| Sept. 11 | Mist | 24° /9° | 0 mm | 6 | |
| Sept. 12 | Sunny | 22° /8° | 0 mm | 6 | |
| Sept. 13 | Overcast | 20° /12° | 6.9 mm | 2 | |
| Sept. 14 | Fog | 23° /10° | 0 mm | 6 | |
| Sept. 15 | Sunny | 21° /7° | 0 mm | 5.8 | |
| Sept. 16 | Overcast | 27° /10° | 0 mm | 5.9 | |
| Sept. 17 | Fog | 24° /15° | 1.4 mm | 4.2 | |
| Sept. 18 | Overcast | 21° /9° | 0 mm | 5 | |
| Sept. 19 |  Cloudy | 19° /5° | 0 mm | 5.6 | |
| Sept. 20 | Mist | 12° /7° | 0.4 mm | 3 | |
| Sept. 21 |  Patchy rain possible | 13° /11° | 0.7 mm | 3 | |
| Sept. 22 | Sunny | 22° /10° | 0 mm | 6 | |
| Sept. 23 |  Light drizzle | 10° /8° | 13.1 mm | 3 | |
| Sept. 24 | Mist | 15° /8° | 0 mm | 3 | |
| Sept. 25 | Patchy rain possible | 20° /13° | 10.4 mm | 4 | |
| Sept. 26 | Light rain shower | 21° /19° | 62.8 mm | 5 | |
| Sept. 27 | Mist | 21° /13° | 1.5 mm | 5 | |
| Sept. 28 | Light rain shower | 14° /11° | 3 mm | 3 | |
| Sept. 29 | Sunny | 26° /13° | 0 mm | 4 | |
| Sept. 30 | Overcast | 22° /13° | 0 mm | 4 | |
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Important Notice
Our weather forecast for Merrimack 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 Merrimack County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Merrimack County in September - FAQ
What are the expected maximum and minimum temperatures in Merrimack County during September?
Enjoy moderate daytime temperatures of up to 22° and cooler nights around 11°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Merrimack County during September?
Significant rainfall exceeding 302 mm is expected in Merrimack County during September, occurring over more than 6 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Merrimack County during September?
The average wind speed in Merrimack County during September is 12 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Merrimack County
Explore the daily rainfall trends and prepare for Merrimack Countys September weather 💧
Typically, Merrimack County has 6 rainy days in September with a total of 302 mm of rainfall.
UV exposure in Merrimack County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Merrimack County?Get accurate weather forecasts for Merrimack County, located at latitude 43.208 and longitude -71.538. Stay updated with localized weather information tailored for Merrimack County.
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