Niigata weather in August
In August, Niigata has daytime highs averaging 28 °C, nights around 23 °C, with 13 wet days, and a sea temperature of 26 °C. Figures are 1991–2020 climate normals.
- 28.3°C Average high
- 22.9°C Average low
- 13days Wet days
- 151mm Rainfall
- 26.3°C Sea temperature
- 14h Daylight
Daily temperatures through August
How August develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 August | 28.9 °C | 23.4 °C | 35 % |
| 11–20 August | 28.4 °C | 23.0 °C | 43 % |
| 21–31 August | 27.6 °C | 22.3 °C | 48 % |
- Average highs fall from 28.9 °C early in August to 27.6 °C by the end of it.
- Rain is most likely over days 21–31 of August (48 % of days) and least likely over days 1–10 (35 %).
What to expect
| Measure | Typical August | Share of the month |
|---|---|---|
| Days above 25 °C | 28 of 31 | 89 % |
| Days above 30 °C | 8.0 of 31 | 26 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 13 of 31 | 42 % |
Conditions in August
| Measure | Average |
|---|---|
| Mean temperature | 25 °C |
| Record high (1991–2020) | 38 °C |
| Record low (1991–2020) | 16 °C |
| Relative humidity | 82 % |
| Wind speed | 14 km/h |
| Cloud cover | 62 % |
August compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| June | 23.1 °C | 122 mm | 72 % |
| July | 26.6 °C | 213 mm | 73 % |
| August | 28.3 °C | 151 mm | 62 % |
| September | 24.7 °C | 142 mm | 67 % |
| October | 19.0 °C | 147 mm | 63 % |
See all twelve months for Niigata
- August is the warmest month in Niigata.
- It is the 8th driest month of the year.
- It ranks 2nd for least cloud cover.
- Days last about 14 hours from sunrise to sunset.
- It rains on 13 of 31 days — 42 % of the month.
- Nights are about 5.4 °C cooler than the middle of the day.
- The hottest August day on record since 1991 reached 38 °C, 9.3 °C above the usual daytime high.
- Beach score: 78 / 100 — see how this is calculated.
QuestionsAugust in Niigata, answered
How warm is Niigata in August?
Daily highs average 28 °C and nights fall to about 23 °C, a spread of 5.4 °C between afternoon and dawn. That makes August the 1st warmest month of the year here.
Does it rain much in Niigata in August?
August averages 151 mm of rain, spread over about 13 of the 31 days — 42 % of the month. Cloud cover averages 62 % of the sky.
Is the sea warm enough to swim in August?
The sea averages 26 °C off Niigata in August. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in August?
Niigata averages 14 hours between sunrise and sunset in August. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.