Climate averages 1991–2020

Saint John’s weather
in September.

A hot, wet month: the 2nd warmest and the 11th driest of the year.

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

Average high 28.7°C Daytime mean, September

Average low 26.2°C Night-time mean, September

Rainfall 127 mm 18 days with ≥1 mm

Daylight 12 h Sunrise to sunset, per day

September is a hot month in Saint John’s: daytime highs average 28.7°C and nights cool to about 26.2°C. By daytime temperature it is the 2nd warmest of the 12 months.

Expect about 127 mm of rain on roughly 18 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 15 min on an average September day.

The nearest other city in this atlas is Basseterre (96 km away). In September its highs average 28.5°C, about as warm as Saint John’s, with 118 mm of rain.

From September to October, average highs fall by 0.5°C to 28.2°C, and monthly rainfall rises from 127 mm to 132 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

Saint John’s climate table

1991–2020

Monthly climate averages for Saint John’s, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	26.2°C24.2°C	24.2°C	32	10.0	11.211 h
February	26.2°C24.0°C	24.0°C	21	7.1	11.612 h
March	26.5°C24.1°C	24.1°C	21	6.6	12.012 h
April	27.2°C24.6°C	24.6°C	33	8.8	12.513 h
May	27.9°C25.4°C	25.4°C	62	12.4	12.913 h
June	28.5°C26.0°C	26.0°C	51	12.1	13.113 h
July	28.6°C26.1°C	26.1°C	78	15.9	13.013 h
August	28.8°C26.3°C	26.3°C	98	17.8	12.713 h
September, selected	28.7°C26.2°C	26.2°C	127	18.0	12.212 h
October	28.2°C26.0°C	26.0°C	132	18.8	11.812 h
November	27.5°C25.4°C	25.4°C	103	15.8	11.311 h
December	26.7°C24.8°C	24.8°C	57	13.3	11.111 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 Saint John’s

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 Saint John’s) is explained once on the Saint John’s year overview and on the Sources, method and limits page.