Nagano in Summer
In summer (June, July and August), Nagano sees average daytime highs around 25°C and overnight lows near 17°C, with 590 mm of rain over about 59 wet days across the season. It is the warmest season of the year and the wettest season of the year.
Over the season highs climb from about 22°C in early June to 26°C by late August. The sky is clear or mostly clear about 14% of the time across summer, and the air most often feels muggy.
Summer is Nagano's best season of the year to visit on our travel score. For the whole year in context, see Nagano's year-round climate.
- Avg daytime high
- 25°C
- warmest season of the year
- Avg overnight low
- 17°C
- Rainfall
- 590 mm
- 59 wet days
- Avg wind
- 4 km/h
- Travel score
- 4.9
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Nagano in Summer
Over the season highs climb from about 22°C in early June to 26°C by late August.
A typical summer day in Nagano reaches about 25°C and drops to 17°C overnight. The warmest of the three months is August, the coolest June.
How summer really feels in Nagano
Once humidity and wind are folded in, summer brings about 0 days that feel above 32°C and 0 that feel at or below 0°C.
summer sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Nagano weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 2° / -6° | 147 | 22.8 | 23.4 | 9.8 | 0.0 |
| Feb | 2° / -5° | 120 | 18.9 | 18.5 | 10.6 | 0.0 |
| Mar | 6° / -2° | 138 | 18.6 | 14.8 | 11.7 | 0.6 |
| Apr | 13° / 3° | 115 | 14.6 | 3.5 | 12.9 | 3.4 |
| May | 19° / 9° | 133 | 14.7 | 0.1 | 13.9 | 5.5 |
| Jun | 23° / 14° | 178 | 18.1 | 0 | 14.5 | 5.2 |
| Jul | 26° / 18° | 243 | 21.7 | 0 | 14.2 | 4.7 |
| Aug | 27° / 19° | 169 | 19.6 | 0 | 13.4 | 4.9 |
| Sep | 23° / 15° | 182 | 17 | 0 | 12.2 | 5.4 |
| Oct | 17° / 8° | 161 | 15.6 | 0.1 | 11.1 | 4.7 |
| Nov | 11° / 2° | 116 | 16.4 | 4.6 | 10 | 2.3 |
| Dec | 5° / -3° | 138 | 20.4 | 17 | 9.5 | 0.2 |
Cloud cover in Summer
The sky is clear or mostly clear about 14% of the time across summer.
Chance of precipitation in Summer
Nagano gets around 590 mm of rain over 59 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 4 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 18 min in early June to 12 h 54 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 5.0 kWh/m².
Hazard calendar for Nagano
In summer, Nagano overlaps its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Nagano sits in the Pacific typhoon belt; the season peaks July–October.
Is summer a good time to visit Nagano?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Nagano for sightseeing.
What to pack for Nagano in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Nagano sees daytime highs around 25°C and nights near 17°C. Pack light clothes and rain gear. Worth having: sun protection. About 59 days see rain.
Sea temperature near Nagano in Summer
The nearest coast averages about 23°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 53 km away) is warmest in August at about 27°C and coldest in March near 10°C.
It's comfortable for a long swim from Jun 20 to Nov 1 — about 4.4 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 13 | 11 | 10 | 11 | 15 | 20 | 23 | 27 | 25 | 22 | 19 | 15 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Warm | Warm | Refreshing | Cool | Cool |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 13 | Bracing |
| Feb | 11 | Bracing |
| Mar | 10 | Bracing |
| Apr | 11 | Bracing |
| May | 15 | Bracing |
| Jun | 20 | Cool |
| Jul | 23 | Refreshing |
| Aug | 27 | Warm |
| Sep | 25 | Warm |
| Oct | 22 | Refreshing |
| Nov | 19 | Cool |
| Dec | 15 | Cool |
UV index in Nagano in Summer
Clear-sky midday UV across summer averages around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Nagano peaks around August 11 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 4 | 5 | 8 | 9 | 9 | 10 | 10 | 9 | 6 | 3 | 2 |
| Level | Moderate | Moderate | High | Very high | Very high | Very high | Very high | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 4 | Moderate |
| Mar | 5 | High |
| Apr | 8 | Very high |
| May | 9 | Very high |
| Jun | 9 | Very high |
| Jul | 10 | Very high |
| Aug | 10 | Extreme |
| Sep | 9 | Very high |
| Oct | 6 | High |
| Nov | 3 | Moderate |
| Dec | 2 | Moderate |
Air quality in Nagano in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in Nagano is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 11 | 14 | 20 | 21 | 20 | 18 | 15 | 13 | 12 | 11 | 11 | 10 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 14 | Moderate |
| Mar | 20 | Moderate |
| Apr | 21 | Moderate |
| May | 20 | Moderate |
| Jun | 18 | Moderate |
| Jul | 15 | Moderate |
| Aug | 13 | Moderate |
| Sep | 12 | Good |
| Oct | 11 | Good |
| Nov | 11 | Good |
| Dec | 10 | Good |
Where is Nagano?
Nagano sits at 36.6°N, 138.2°E, 372 m above sea level, in Japan. The nearest listed city is Suzaka, 12 km away.
Topography around Nagano
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Nagano.
Within 3 km, the terrain around Nagano has significant variations in elevation — a maximum elevation change of 548 m around an average of 450 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,583 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,130 m.
The land around Nagano is covered by artificial surfaces (60%) and trees (36%) within 3 km, trees (68%) within 16 km, and trees (74%) within 80 km.
Japan travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 100 V · 50 / 60 Hz
- Prices
- ≈ 65% of US
- price level, 2025
- GDP per capita
- $35,951
- 2025
- Happiness
- 6.1 / 10
- World Happiness, 2025
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 0.2
- per 100k, 2023
- Road deaths
- 3.6
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very low
- EF EPI 446
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Nagano (36.65°, 138.1833°, elevation 372 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.