Climate averages 1991–2020
Watford weather
in September.
A mild, moderately wet month: the 4th warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Watford: daytime highs average 18.1°C and nights cool to about 11.1°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 51 mm of rain on roughly 9 days, which makes September a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 43 min on an average September day.
The nearest other city in this atlas is Harrow (10 km away). In September its highs average 18.1°C, about as warm as Watford, with 47 mm of rain.
Among the 143 cities listed in the United Kingdom, Watford ranks joint 30th of 143 for the warmest September highs and joint 31st of 143 for the driest September (rainfall, lowest first). The mean September high of those 143 cities is 17.3°C; Watford is 0.8°C warmer than that mean.
From September to October, average highs fall by 3.9°C to 14.2°C, and monthly rainfall rises from 51 mm to 60 mm.
The annual picture
September in context
Monthly rainfall
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
Watford climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.1°C2.3°C | 2.3°C | 54 | 11.2 | 8.48 h |
| February | 7.6°C2.2°C | 2.2°C | 45 | 9.9 | 9.910 h |
| March | 10.0°C3.4°C | 3.4°C | 44 | 10.3 | 11.812 h |
| April | 12.9°C5.1°C | 5.1°C | 50 | 11.4 | 13.814 h |
| May | 16.0°C8.1°C | 8.1°C | 56 | 10.5 | 15.616 h |
| June | 18.9°C11.1°C | 11.1°C | 58 | 10.5 | 16.617 h |
| July | 21.1°C13.3°C | 13.3°C | 58 | 11.2 | 16.216 h |
| August | 20.8°C13.3°C | 13.3°C | 62 | 10.7 | 14.615 h |
| September, selected | 18.1°C11.1°C | 11.1°C | 51 | 9.4 | 12.713 h |
| October | 14.2°C8.4°C | 8.4°C | 60 | 11.3 | 10.711 h |
| November | 10.0°C5.1°C | 5.1°C | 62 | 11.2 | 8.99 h |
| December | 7.4°C2.9°C | 2.9°C | 57 | 11.2 | 7.98 h |
Rainfall is the average of the 30 separate monthly totals. A rain 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
- Harrow in SeptemberUnited Kingdom · 10 kmHigh 18.1°C · Low 11.1°C · 47 mm rain
- St Albans in SeptemberUnited Kingdom · 11 kmHigh 18.0°C · Low 10.9°C · 49 mm rain
- Hemel Hempstead in SeptemberUnited Kingdom · 12 kmHigh 17.7°C · Low 10.7°C · 51 mm rain
- Uxbridge in SeptemberUnited Kingdom · 13 kmHigh 18.2°C · Low 11.1°C · 47 mm rain
- Hayes in SeptemberUnited Kingdom · 16 kmHigh 18.2°C · Low 11.1°C · 47 mm rain
- Archway in SeptemberUnited Kingdom · 21 kmHigh 18.2°C · Low 11.1°C · 47 mm rain
- Slough in SeptemberUnited Kingdom · 21 kmHigh 18.3°C · Low 11.0°C · 47 mm rain
- Enfield Town in SeptemberUnited Kingdom · 21 kmHigh 18.4°C · Low 11.3°C · 48 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 Watford) is explained once on the Watford year overview and on the Sources, method and limits page.
Hemel Hempstead lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.