Climate averages 1991–2020
Koga weather
in May.
A warm, wet month: the 5th warmest and the 7th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a warm month in Koga: daytime highs average 22.3°C and nights cool to about 12.6°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 153 mm of rain on roughly 14 days, which makes May a wet month (the 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 04 min on an average May day.
The nearest other city in this atlas is Kazo (13 km away). In May its highs average 22.5°C, about as warm as Koga, with 127 mm of rain.
Among the 303 cities listed in Japan, Koga ranks joint 92nd of 303 for the warmest May highs and joint 191st of 303 for the driest May (rainfall, lowest first). The mean May high of those 303 cities is 21.3°C; Koga is 1.0°C warmer than that mean.
From May to June, average highs rise by 2.6°C to 25.0°C, and monthly rainfall rises from 153 mm to 177 mm.
The annual picture
May 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
Koga climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.6°C-2.1°C | -2.1°C | 55 | 6.0 | 10.010 h |
| February | 8.8°C-1.3°C | -1.3°C | 55 | 6.9 | 10.811 h |
| March | 12.5°C1.9°C | 1.9°C | 106 | 11.6 | 11.912 h |
| April | 17.7°C7.1°C | 7.1°C | 120 | 12.6 | 13.113 h |
| May, selected | 22.3°C12.6°C | 12.6°C | 153 | 13.7 | 14.114 h |
| June | 25.0°C17.2°C | 17.2°C | 177 | 16.5 | 14.615 h |
| July | 28.4°C21.3°C | 21.3°C | 209 | 18.7 | 14.414 h |
| August | 29.8°C22.6°C | 22.6°C | 161 | 16.3 | 13.514 h |
| September | 26.0°C19.2°C | 19.2°C | 206 | 16.2 | 12.412 h |
| October | 20.5°C13.0°C | 13.0°C | 200 | 13.9 | 11.311 h |
| November | 15.2°C6.3°C | 6.3°C | 88 | 9.4 | 10.310 h |
| December | 10.0°C0.7°C | 0.7°C | 54 | 6.8 | 9.710 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
May in nearby cities
- Kazo in MayJapan · 13 kmHigh 22.5°C · Low 12.9°C · 127 mm rain
- Kukichūō in MayJapan · 13 kmHigh 22.6°C · Low 12.9°C · 128 mm rain
- Oyama in MayJapan · 15 kmHigh 22.1°C · Low 12.4°C · 153 mm rain
- Tatebayashi in MayJapan · 18 kmHigh 22.2°C · Low 12.3°C · 152 mm rain
- Sano in MayJapan · 19 kmHigh 22.2°C · Low 12.3°C · 152 mm rain
- Kōnosu in MayJapan · 22 kmHigh 22.3°C · Low 12.8°C · 127 mm rain
- Tochigi in MayJapan · 22 kmHigh 22.0°C · Low 12.1°C · 173 mm rain
- Kasukabe in MayJapan · 22 kmHigh 22.6°C · Low 13.2°C · 128 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 Koga) is explained once on the Koga year overview and on the Sources, method and limits page.
Oyama lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.