Climate averages 1991–2020

Ōmihachiman weather
in September.

A warm, 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 26.2°C Daytime mean, September

Average low 19.1°C Night-time mean, September

Rainfall 179 mm 12 days with ≥1 mm

Daylight 12 h Sunrise to sunset, per day

September is a warm month in Ōmihachiman: daytime highs average 26.2°C and nights cool to about 19.1°C. By daytime temperature it is the 3rd warmest of the 12 months.

Expect about 179 mm of rain on roughly 12 days, which makes September a wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 26 min on an average September day.

The nearest other city in this atlas is Youkaichi (9 km away). In September its highs average 26.2°C, about as warm as Ōmihachiman, with 202 mm of rain.

Among the 303 cities listed in Japan, Ōmihachiman ranks joint 133rd of 303 for the warmest September highs and joint 115th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Ōmihachiman is 0.5°C warmer than that mean.

From September to October, average highs fall by 5.6°C to 20.5°C, and monthly rainfall falls from 179 mm to 152 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

Ōmihachiman climate table

1991–2020

Monthly climate averages for Ōmihachiman, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	7.1°C0.0°C	0.0°C	81	13.9	10.110 h
February	8.0°C0.0°C	0.0°C	78	13.0	10.911 h
March	11.8°C2.6°C	2.6°C	116	13.5	11.912 h
April	17.2°C7.4°C	7.4°C	123	11.6	13.113 h
May	21.9°C12.6°C	12.6°C	148	11.6	14.014 h
June	25.3°C17.3°C	17.3°C	186	14.0	14.514 h
July	28.9°C21.8°C	21.8°C	210	15.9	14.314 h
August	30.2°C22.8°C	22.8°C	122	12.3	13.513 h
September, selected	26.2°C19.1°C	19.1°C	179	12.3	12.412 h
October	20.5°C13.2°C	13.2°C	152	10.8	11.311 h
November	15.1°C7.5°C	7.5°C	81	9.0	10.410 h
December	9.6°C2.4°C	2.4°C	75	11.6	9.810 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 Ōmihachiman

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