Weather in Saitama

Rain is wet season runs from April to October, inside an annual total of 1449 mm. The wettest month is September at 201 mm; the driest is February at 48 mm.

Saitama is in Japan at 35.9°N. The 2001–2020 NASA POWER daily record describes a continental climate with a wide temperature swing. August is the warmest month (average 26.0°C, high 30.6°C) and January is the coolest (average 1.8°C, low -2.9°C). On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are June, July, and September.

Rain through the year

The wet season in Saitama starts in April and ends in October (April, May, June, July, August, September, and October). September is the core of it at 201 mm. February is the other extreme, with 48 mm.

A rainy day here is a day with at least 1 mm in the NASA POWER series. September averages 15 such days; February averages 6.

How warm Saitama gets

Monthly average highs run from 6.4°C in January to 30.6°C in August. Nights follow the same curve: -2.9°C in January and 21.5°C in August.

Mean high across all twelve months is 18.8°C and mean low is 8.6°C. These are 20-year grid averages, so a city station can read a few degrees warmer or cooler.

The calendar in Saitama

January is the coolest month, with lows around -2.9°C and highs near 6.4°C. Rainfall is 53 mm. February is the driest month, averaging only 48 mm across 6 rainy days. Highs sit near 7.9°C. March stands apart from the months beside it: 12.0°C / 0.3°C and 89 mm. The wet season opens in April. Expect 107 mm and 10 rainy days, with nights around 5.3°C. In May, Saitama averages 23.0°C by day and 11.2°C at night, with 126 mm of rain. June brings 159 mm and 16 rainy days; temperatures run from 16.2°C to 25.9°C.

July stands apart from the months beside it: 29.6°C / 20.6°C and 180 mm. Peak heat arrives in August: 30.6°C by day, 21.5°C at night, and 81% humidity. September is the wettest month — 201 mm and 15 rainy days, with 82% humidity. October closes the wet season: 195 mm over 12 rainy days, then the calendar dries. November: 15.3°C high, 4.7°C low, 77 mm rain, 81% humidity. December stands apart from the months beside it: 9.4°C / -0.4°C and 55 mm.

Best months to visit Saitama

The three months with the highest comfort score are June, July, and September: June (21.1°C average, 159 mm, 80% humidity); July (25.1°C average, 180 mm, 82% humidity); September (22.1°C average, 201 mm, 82% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you want the wet season itself — fewer crowds, greener landscape, heavier rain — aim at April–October instead of the score.

How Saitama compares inside Japan

Tokyo is about 25 km away: Saitama is 1.4°C cooler than Tokyo in its hottest month and 245 mm drier over the year than Tokyo. Tokyo’s wettest month is October (246 mm) versus September here.

Yokohama is about 53 km away: Saitama is about as warm as Yokohama at the hot peak and 187 mm drier over the year than Yokohama. Yokohama’s wettest month is October (222 mm) versus September here.

Nagoya is about 262 km away: Saitama is 1.3°C cooler than Nagoya in its hottest month and 292 mm drier over the year than Nagoya. Nagoya’s wettest month is July (225 mm) versus September here.