Climate averages 1991–2020

Bolton weather
in September.

A mild, moderately wet month: the 4th warmest and the 5th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 16.1°C Daytime mean, September

Average low 9.8°C Night-time mean, September

Rainfall 77 mm 13 days with ≥1 mm

Daylight 13 h Sunrise to sunset, per day

September is a mild month in Bolton: daytime highs average 16.1°C and nights cool to about 9.8°C. By daytime temperature it is the 4th warmest of the 12 months.

Expect about 77 mm of rain on roughly 13 days, which makes September a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 45 min on an average September day.

The nearest other city in this atlas is Wigan (14 km away). In September its highs average 16.6°C, 0.5°C warmer than Bolton, with 78 mm of rain.

Among the 143 cities listed in the United Kingdom, Bolton ranks 123rd of 143 for the warmest September highs and joint 129th of 143 for the driest September (rainfall, lowest first). The mean September high of those 143 cities is 17.3°C; Bolton is 1.2°C cooler than that mean.

From September to October, average highs fall by 3.4°C to 12.7°C, and monthly rainfall rises from 77 mm to 91 mm.

The annual picture

September in context

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Bolton climate table

1991–2020

Monthly climate averages for Bolton, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	6.2°C1.7°C	1.7°C	83	15.1	8.18 h
February	6.8°C1.4°C	1.4°C	72	13.3	9.810 h
March	8.9°C2.4°C	2.4°C	70	13.0	11.812 h
April	11.5°C4.0°C	4.0°C	65	12.7	14.014 h
May	14.5°C6.9°C	6.9°C	67	12.7	15.916 h
June	16.9°C9.9°C	9.9°C	81	13.8	17.017 h
July	18.6°C11.8°C	11.8°C	82	14.8	16.516 h
August	18.2°C11.8°C	11.8°C	89	15.1	14.815 h
September, selected	16.1°C9.8°C	9.8°C	77	12.7	12.813 h
October	12.7°C7.3°C	7.3°C	91	14.7	10.611 h
November	8.9°C4.3°C	4.3°C	91	16.1	8.79 h
December	6.5°C2.1°C	2.1°C	99	15.5	7.68 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

Distance from Bolton

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 limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Bolton) is explained once on the Bolton year overview and on the Sources, method and limits page.

Warrington lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.