Climate averages 1991–2020

Alkmaar weather
in September.

A mild, moderately wet month: the 3rd warmest and the 10th driest of the year.

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

Average high 17.4°C Daytime mean, September

Average low 13.7°C Night-time mean, September

Rainfall 82 mm 13 days with ≥1 mm

Daylight 13 h Sunrise to sunset, per day

September is a mild month in Alkmaar: daytime highs average 17.4°C and nights cool to about 13.7°C. By daytime temperature it is the 3rd warmest of the 12 months.

Expect about 82 mm of rain on roughly 13 days, which makes September a moderately wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 44 min on an average September day.

The nearest other city in this atlas is Purmerend (20 km away). In September its highs average 17.9°C, about as warm as Alkmaar, with 69 mm of rain.

Among the 44 cities listed in the Netherlands, Alkmaar ranks 44th of 44 for the warmest September highs and 40th of 44 for the driest September (rainfall, lowest first). The mean September high of those 44 cities is 18.4°C; Alkmaar is 0.9°C cooler than that mean.

From September to October, average highs fall by 3.6°C to 13.8°C, and monthly rainfall rises from 82 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

Alkmaar climate table

1991–2020

Monthly climate averages for Alkmaar, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	5.9°C2.9°C	2.9°C	68	13.4	8.28 h
February	6.0°C2.7°C	2.7°C	53	10.9	9.810 h
March	8.2°C4.2°C	4.2°C	49	10.5	11.812 h
April	11.4°C6.6°C	6.6°C	37	8.8	13.914 h
May	14.6°C10.0°C	10.0°C	50	9.6	15.716 h
June	17.2°C12.9°C	12.9°C	55	10.3	16.817 h
July	19.5°C15.3°C	15.3°C	67	11.8	16.316 h
August	19.9°C15.7°C	15.7°C	84	12.8	14.715 h
September, selected	17.4°C13.7°C	13.7°C	82	12.6	12.713 h
October	13.8°C10.4°C	10.4°C	91	14.4	10.711 h
November	9.8°C6.8°C	6.8°C	79	15.5	8.89 h
December	6.9°C4.0°C	4.0°C	79	14.5	7.78 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 Alkmaar

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 Alkmaar) is explained once on the Alkmaar year overview and on the Sources, method and limits page.