Mild
Average highs are around 21°C, so days are mild rather than hot.
September verdict
Nagano, Nagano, Japan in September
Weather score39Poor
Poor for holiday weather
Average highs are around 21°C, so days are mild rather than hot. Sunshine averages 4.1h per day, so this is not one of the brighter months. Rainfall averages 195mm, so showers are a real planning factor.
September weather
Monthly averages
Temp
21°C
Rain
195mm
Sun
4.1h
Sea
26°C
Weather score
39
Poor
Seasonal climate calendar
TemperatureTemp
RainRain
SunSun
SwimSwim
Weather scoreWeather score
Trip feel
Wet
Rainfall averages 195mm, so showers are a real planning factor.
Limited sun
Sunshine averages 4.1h per day, so this is not one of the brighter months.
Swimmable
Sea temperatures average 26°C, which can work for swimming but may feel fresh.
Map
Weather map
Compare Nagano, Nagano, Japan with nearby places by weather score, rain, sun, temperature, and swim conditions.
Temperature
September21°C average high
September sits in the warmer part of the year, so midday sightseeing can feel heavier than in cooler months.
Warmest monthsJune to September
This stretch sets the upper range for average daytime heat.
Rain
September195mm average rain
September is one of Nagano's wettest months, so rain is likely to be a major planning factor.
Driest monthsJanuary to May and October to December
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
Sun
September4.1 hours average sun
September is below Nagano's yearly sunshine average, so bright-day planning is less reliable than in peak months.
Brightest monthsApril to May
This stretch has the strongest sunshine in the monthly averages.
Sea temperature
September26°C average sea
September is one of Nagano's warmest sea months, when swimming comfort is usually strongest.
Warmest seaJuly to September
Sea temperatures are usually near 24°C in this stretch, so swimming comfort is at its strongest.
Weather score
September39 weather score
September sits close to Nagano's yearly weather-score average, giving a typical overall read on the month.
Best weather monthsJuly to September
These months have the strongest weather score in the monthly averages.
