Hachimantai in Summer
In summer (June, July and August), Hachimantai sees average daytime highs around 23°C and overnight lows near 16°C, with 389 mm of rain over about 44 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 20°C in early June to 24°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 Hachimantai's best season of the year to visit on our travel score. For the whole year in context, see Hachimantai's year-round climate.
- Avg daytime high
- 23°C
- warmest season of the year
- Avg overnight low
- 16°C
- Rainfall
- 389 mm
- 44 wet days
- Avg wind
- 7 km/h
- Travel score
- 5.7
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Hachimantai in Summer
Over the season highs climb from about 20°C in early June to 24°C by late August.
A typical summer day in Hachimantai reaches about 23°C and drops to 16°C overnight. The warmest of the three months is August, the coolest June.
How summer really feels in Hachimantai
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.
Hachimantai 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 | -1° / -9° | 60 | 10.5 | 13.2 | 9.5 | 0.0 |
| Feb | 0° / -8° | 59 | 10.4 | 12.1 | 10.4 | 0.0 |
| Mar | 4° / -4° | 90 | 14.2 | 12.1 | 11.7 | 0.2 |
| Apr | 11° / 2° | 90 | 14.1 | 4 | 13 | 2.6 |
| May | 17° / 8° | 93 | 12.7 | 0.3 | 14.2 | 5.1 |
| Jun | 21° / 13° | 105 | 12.8 | 0 | 14.8 | 5.7 |
| Jul | 24° / 17° | 144 | 16.4 | 0 | 14.5 | 5.6 |
| Aug | 25° / 18° | 141 | 14.9 | 0 | 13.6 | 5.9 |
| Sep | 21° / 14° | 138 | 12.9 | 0 | 12.3 | 5.8 |
| Oct | 15° / 7° | 111 | 11.2 | 0.1 | 10.9 | 4.5 |
| Nov | 8° / 1° | 76 | 12.8 | 4 | 9.8 | 1.4 |
| Dec | 2° / -5° | 74 | 12 | 12 | 9.2 | 0.0 |
Cloud cover in Summer
The sky is clear or mostly clear about 14% of the time across summer.
Chance of precipitation in Summer
Hachimantai gets around 389 mm of rain over 44 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 7 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 36 min in early June to 13 hours 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 4.6 kWh/m².
Is summer a good time to visit Hachimantai?
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 Hachimantai for sightseeing.
What to pack for Hachimantai in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Hachimantai sees daytime highs around 23°C and nights near 16°C. Pack rain gear. Worth having: light clothes and sun protection. About 44 days see rain.
Sea temperature near Hachimantai in Summer
The nearest coast averages about 18°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 68 km away) is warmest in August at about 21°C and coldest in March near 6°C.
It's comfortable for a long swim from Aug 8 to Sep 25 — about 1.6 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 10 | 8 | 6 | 7 | 10 | 14 | 18 | 21 | 21 | 18 | 15 | 12 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Refreshing | Cool | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 10 | Bracing |
| Feb | 8 | Bracing |
| Mar | 6 | Bracing |
| Apr | 7 | Bracing |
| May | 10 | Bracing |
| Jun | 14 | Bracing |
| Jul | 18 | Cool |
| Aug | 21 | Refreshing |
| Sep | 21 | Refreshing |
| Oct | 18 | Cool |
| Nov | 15 | Cool |
| Dec | 12 | Bracing |
UV index in Hachimantai in Summer
Clear-sky midday UV across summer averages around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Hachimantai peaks around August 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 4 | 6 | 8 | 8 | 6 | 9 | 7 | 5 | 2 | 2 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | High | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 4 | Moderate |
| Apr | 6 | High |
| May | 8 | Very high |
| Jun | 8 | Very high |
| Jul | 6 | High |
| Aug | 9 | Very high |
| Sep | 7 | High |
| Oct | 5 | Moderate |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Air quality in Hachimantai 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 Hachimantai is worst in April — around 20 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (December, 9 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 | 19 | 20 | 19 | 14 | 12 | 11 | 11 | 12 | 11 | 9 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 14 | Moderate |
| Mar | 19 | Moderate |
| Apr | 20 | Moderate |
| May | 19 | Moderate |
| Jun | 14 | Moderate |
| Jul | 12 | Moderate |
| Aug | 11 | Good |
| Sep | 11 | Good |
| Oct | 12 | Good |
| Nov | 11 | Good |
| Dec | 9 | Good |
Where is Hachimantai?
Hachimantai sits at 39.9°N, 141.1°E, 228 m above sea level, in Japan. The nearest listed city is Takizawa, 11 km away.
Topography around Hachimantai
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Hachimantai.
Within 3 km, the terrain around Hachimantai has only modest variations in elevation — a maximum elevation change of 149 m around an average of 245 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,870 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,117 m.
The land around Hachimantai is covered by cropland (46%) and trees (38%) within 3 km, trees (75%) within 16 km, and trees (84%) 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 Hachimantai (39.8998°, 141.1299°, elevation 228 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.