Climate averages 1991–2020
Danbury weather
in September.
A warm, wet month: the 4th warmest and the joint 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Danbury: daytime highs average 23.0°C and nights cool to about 14.6°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 108 mm of rain on roughly 9 days, which makes September a wet month (the joint 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 31 min on an average September day.
The nearest other city in this atlas is Norwalk (31 km away). In September its highs average 23.1°C, about as warm as Danbury, with 94 mm of rain.
Among the 498 cities listed in the United States, Danbury ranks joint 408th of 498 for the warmest September highs and joint 420th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Danbury is 3.9°C cooler than that mean.
From September to October, average highs fall by 6.7°C to 16.3°C, and monthly rainfall stays at 108 mm.
The annual picture
September in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Danbury climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 2.0°C-6.0°C | -6.0°C | 88 | 9.4 | 9.610 h |
| February | 3.4°C-5.4°C | -5.4°C | 78 | 8.8 | 10.611 h |
| March | 7.8°C-1.5°C | -1.5°C | 106 | 11.1 | 11.912 h |
| April | 14.4°C4.4°C | 4.4°C | 97 | 11.3 | 13.313 h |
| May | 19.9°C10.2°C | 10.2°C | 99 | 12.0 | 14.514 h |
| June | 25.0°C15.6°C | 15.6°C | 111 | 12.0 | 15.115 h |
| July | 28.1°C18.9°C | 18.9°C | 108 | 11.3 | 14.815 h |
| August | 27.1°C18.3°C | 18.3°C | 115 | 10.9 | 13.814 h |
| September, selected | 23.0°C14.6°C | 14.6°C | 108 | 9.3 | 12.513 h |
| October | 16.3°C8.6°C | 8.6°C | 108 | 9.4 | 11.111 h |
| November | 10.1°C2.8°C | 2.8°C | 86 | 8.6 | 9.910 h |
| December | 4.6°C-2.1°C | -2.1°C | 104 | 10.5 | 9.29 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Norwalk in SeptemberUnited States · 31 kmHigh 23.1°C · Low 16.4°C · 94 mm rain
- Bridgeport in SeptemberUnited States · 33 kmHigh 22.8°C · Low 16.4°C · 103 mm rain
- Waterbury in SeptemberUnited States · 38 kmHigh 23.2°C · Low 14.6°C · 101 mm rain
- Stamford in SeptemberUnited States · 39 kmHigh 23.2°C · Low 16.4°C · 94 mm rain
- New Haven in SeptemberUnited States · 45 kmHigh 22.6°C · Low 16.2°C · 109 mm rain
- Greenburgh in SeptemberUnited States · 52 kmHigh 23.3°C · Low 15.9°C · 95 mm rain
- New Britain in SeptemberUnited States · 63 kmHigh 23.3°C · Low 14.1°C · 97 mm rain
- Yonkers in SeptemberUnited States · 64 kmHigh 23.7°C · Low 15.8°C · 101 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Danbury) is explained once on the Danbury year overview and on the Sources, method and limits page.