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Itoigawa, Japan climate

Cfa Humid subtropical

Itoigawa has a seasonal mild-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is August with an average daily high near 30°C, while the coldest is January averaging around 1°C at night. Around 2902 mm of precipitation falls each year, peaking in December (407 mm) and easing off in May (120 mm).

☀️ Summers
Warm
Highs near 30°C in August.
❄️ Winters
Chilly
Lows near 1°C in January.
🌧️ Rain
Very wet
About 2902 mm of rain a year.
Wettest in December
Sky & trend
Often grey
Overcast skies dominate much of the year.

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures TEMPERATURE °C -10°10°20°30°40° PRECIPITATION (mm) 0205410 JanAprJulOct

Hours of sunshine per day

Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER) 0h2h3h4h6h J: ~0.9 hours of sun/dayF: ~1.6 hours of sun/dayM: ~2.8 hours of sun/dayA: ~4.1 hours of sun/dayM: ~4.5 hours of sun/dayJ: ~3.6 hours of sun/dayJ: ~3.6 hours of sun/dayA: ~4.9 hours of sun/dayS: ~3.6 hours of sun/dayO: ~3.4 hours of sun/dayN: ~2.4 hours of sun/dayD: ~1.3 hours of sun/day JFMAMJJASOND Sun hours per day (est.)

Itoigawa climate normals (1991–2020)

JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)7711162124293027211610
Avg temp (°C)44712172125272317127
Avg low (°C)113813182224201483
Precipitation (mm)355226204135120168238223251232341407
Jan – JunJanFebMarAprMayJun
Avg high (°C)7711162124
Avg temp (°C)447121721
Avg low (°C)11381318
Precipitation (mm)355226204135120168
Jul – DecJulAugSepOctNovDec
Avg high (°C)293027211610
Avg temp (°C)25272317127
Avg low (°C)2224201483
Precipitation (mm)238223251232341407

Sky & atmosphere

JanFebMarAprMayJunJulAugSepOctNovDec
Cloud cover (%)918576686875756371697687
Relative humidity (%)908782787782848283828488
Wind speed (m/s)3.83.73.22.51.91.51.51.61.92.22.73.4
Jan – JunJanFebMarAprMayJun
Cloud cover (%)918576686875
Relative humidity (%)908782787782
Wind speed (m/s)3.83.73.22.51.91.5
Jul – DecJulAugSepOctNovDec
Cloud cover (%)756371697687
Relative humidity (%)848283828488
Wind speed (m/s)1.51.61.92.22.73.4
Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from the Japan Meteorological Agency, measured at Itoigawa, about 2 km from the city centre.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →