Niigata

Shirone, Japan Climate

NASA POWER reanalysis for the half-degree grid cell around Shirone, 1991-2020; a grid cell is an area average and can differ from a thermometer in town by several degrees

The warmest month is August, with an average high of 27°C; the coldest is February, with an average low of 3°C. A normal year brings 1695 mm of precipitation.

Temperature through the year

The normal daily high and low. The line marks today.

Normal daily high and low temperature at Shirone through the year, in °C, with the record for each date.-10010203040JanFebMarAprMayJunJulAugSepOctNovDec
  • Normal low
  • Normal high
  • Reanalysis extreme high
  • Reanalysis extreme low

Normals for Sep 25

Normal high
23°C
Normal low
20°C
Reanalysis high
27°Cin 1992
Reanalysis low
18°Cin 2010
Chance of a wet day
50%
Daylight
12 h 03 min

Month by month

Averages for 1991-2020. Wet days have at least 1 mm of precipitation in the reanalysis. Each month links to its own page.

MonthAvg highAvg lowWarmestColdestPrecipitationWet days
January6°C4°C13°C (1997)-3°C (2018)167 mm24.8
February6°C3°C15°C (2010)-3°C (1996)110 mm19.8
March8°C5°C15°C (2016)0°C (2013)105 mm18.6
April12°C8°C22°C (2019)3°C (2012)93 mm12.0
May17°C13°C26°C (2019)6°C (2013)93 mm12.4
June21°C18°C28°C (2009)13°C (2017)120 mm12.0
July25°C22°C32°C (2000)17°C (1996)198 mm15.5
August27°C24°C34°C (1994)19°C (2009)146 mm15.5
September24°C22°C32°C (2020)16°C (2001)144 mm15.0
October19°C17°C27°C (2019)10°C (1997)146 mm15.5
November14°C11°C21°C (2018)3°C (1992)171 mm21.0
December9°C6°C18°C (2018)-1°C (2002)202 mm24.8
Year16°C13°C1695 mm207

Precipitation

Rain and melted snow together. The chance of a wet day is the share of days with at least 1 mm of precipitation in the reanalysis.

1695 mm in a normal year, most in December.

Chance of a wet day

The chance of at least 1 mm of precipitation in the reanalysis on each date at Shirone, in percent.020406080100JanFebMarAprMayJunJulAugSepOctNovDec
  • Chance of a wet day

Humidity and comfort

NASA POWER reanalysis, 1991-2020, for the grid cell around Shirone.

The muggiest month is August, when 95 percent of days are muggy or worse, with a mean dew point of 18°C or more.

MonthDew pointHumidityDryComfortableHumidMuggyOppressiveMiserable
January2°C79%100%0%0%0%0%0%
February1°C76%100%0%0%0%0%0%
March2°C74%100%0%0%0%0%0%
April6°C77%100%0%0%0%0%0%
May12°C80%66%30%5%0%0%0%
June17°C82%6%27%45%21%1%0%
July21°C85%0%0%10%41%45%4%
August22°C80%0%1%5%24%51%20%
September19°C76%3%15%27%33%20%2%
October13°C74%49%30%17%4%0%0%
November8°C75%92%8%0%0%0%0%
December4°C79%100%0%0%0%0%0%

Comfort is judged by the day's mean dew point: dry below 13°C, comfortable to 16°C, humid to 18°C, muggy to 21°C, oppressive to 24°C, miserable above.

Clouds

Average share of the sky covered, from satellite (CERES and GEWEX SRB) by way of NASA POWER, 1991-2020.

The clearest month is August, with the sky 71 percent covered on average; the cloudiest is January, at 94 percent.

Wind

The mean wind speed over the whole day, from the MERRA-2 reanalysis by way of NASA POWER. Gusts run well above it.

The windiest month is January, averaging 27.0 km/h at 10 meters (33 feet) above the ground.

Daylight and sunshine

The longest day is Jun 15, with 14 h 47 min of daylight; the shortest is Dec 16, with 9 h 33 min.

Hours of daylight at Shirone through the year.0510152025JanFebMarAprMayJunJulAugSepOctNovDec
  • Day length

Solar energy

Average daily sunshine reaching the ground on a flat surface, in kilowatt-hours per square meter, clouds included.

Sunrise and sunset calendar

Month pages

The weather in Shirone in each month, day by day.

What this means

A normal is the average of the thirty years 1991 to 2020, the period the World Meteorological Organization and NOAA use for comparison. It is an average, not a forecast: most days depart from it, and some by a long way.

Where no station record is within reach, the extremes shown are the highest and lowest the reanalysis produced for the date in 1991-2020, not measured records.

Cloud, humidity, wind and sunshine come from a reanalysis: a weather model run over the past with every observation fed in, averaged over a grid cell about 50 km across. It is consistent everywhere on Earth; it smooths local detail such as a lake shore or a valley.

More for this place

Nearby

Sources

Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.