Oga in Summer
In summer (June, July and August), Oga sees average daytime highs around 23°C and overnight lows near 21°C, with 488 mm of rain over about 40 wet days across the season. It is the warmest season of the year and the 3rd-wettest season.
Over the season highs climb from about 18°C in early June to 25°C by late August. The sky is clear or mostly clear about 27% of the time across summer, and the air most often feels muggy.
Summer is Oga's best season of the year to visit on our travel score. For the whole year in context, see Oga's year-round climate.
- Avg daytime high
- 23°C
- warmest season of the year
- Avg overnight low
- 21°C
- Rainfall
- 488 mm
- 40 wet days
- Avg wind
- 16 km/h
- Travel score
- 6.0
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Oga in Summer
Over the season highs climb from about 18°C in early June to 25°C by late August.
A typical summer day in Oga reaches about 23°C and drops to 21°C overnight. The warmest of the three months is August, the coolest June.
How summer really feels in Oga
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.
Oga 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 | 4° / 1° | 169 | 25.4 | 17.9 | 9.5 | 0.0 |
| Feb | 4° / 1° | 119 | 20.5 | 14.2 | 10.4 | 0.0 |
| Mar | 6° / 3° | 108 | 17.2 | 6.7 | 11.7 | 0.5 |
| Apr | 10° / 7° | 98 | 12.7 | 0.3 | 13 | 2.1 |
| May | 14° / 12° | 117 | 12.6 | 0 | 14.2 | 4.1 |
| Jun | 19° / 17° | 120 | 11 | 0 | 14.8 | 5.9 |
| Jul | 23° / 21° | 190 | 14.4 | 0 | 14.5 | 6.0 |
| Aug | 26° / 23° | 178 | 14.1 | 0 | 13.6 | 6.2 |
| Sep | 23° / 21° | 180 | 14 | 0 | 12.3 | 6.0 |
| Oct | 18° / 15° | 166 | 15.3 | 0 | 10.9 | 5.0 |
| Nov | 12° / 9° | 174 | 19.6 | 1.2 | 9.8 | 2.5 |
| Dec | 7° / 4° | 203 | 24.8 | 10.2 | 9.2 | 0.6 |
Cloud cover in Summer
The sky is clear or mostly clear about 27% of the time across summer.
Chance of precipitation in Summer
Oga gets around 488 mm of rain over 40 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 16 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 5.4 kWh/m².
Hazard calendar for Oga
In summer, Oga overlaps its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Oga sits in the Pacific typhoon belt; the season peaks July–October.
Is summer a good time to visit Oga?
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 Oga for sightseeing.
What to pack for Oga in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Oga sees daytime highs around 23°C and nights near 21°C. Pack rain gear. Worth having: light clothes and sun protection. About 40 days see rain.
Sea temperature near Oga in Summer
The nearest coast averages about 22°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea offshore is warmest in August at about 25°C and coldest in March near 9°C.
It's comfortable for a long swim from Jun 30 to Oct 23 — about 3.8 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 11 | 9 | 9 | 10 | 14 | 18 | 22 | 25 | 24 | 21 | 17 | 14 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Warm | Warm | Refreshing | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 11 | Bracing |
| Feb | 9 | Bracing |
| Mar | 9 | Bracing |
| Apr | 10 | Bracing |
| May | 14 | Bracing |
| Jun | 18 | Cool |
| Jul | 22 | Refreshing |
| Aug | 25 | Warm |
| Sep | 24 | Warm |
| Oct | 21 | Refreshing |
| Nov | 17 | Cool |
| Dec | 14 | Bracing |
UV index in Oga 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 Oga peaks around August 19 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (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) | 1 | 2 | 3 | 6 | 8 | 7 | 5 | 9 | 7 | 4 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Moderate | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Moderate |
| Mar | 3 | Moderate |
| Apr | 6 | High |
| May | 8 | Very high |
| Jun | 7 | Very high |
| Jul | 5 | Moderate |
| Aug | 9 | Very high |
| Sep | 7 | High |
| Oct | 4 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Air quality in Oga 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 Oga is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (September, 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 | 15 | 20 | 21 | 18 | 13 | 11 | 10 | 9 | 10 | 10 | 10 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 15 | Moderate |
| Mar | 20 | Moderate |
| Apr | 21 | Moderate |
| May | 18 | Moderate |
| Jun | 13 | Moderate |
| Jul | 11 | Good |
| Aug | 10 | Good |
| Sep | 9 | Good |
| Oct | 10 | Good |
| Nov | 10 | Good |
| Dec | 10 | Good |
Where is Oga?
Oga sits at 39.9°N, 139.8°E, 6 m above sea level, in Japan. The nearest listed city is Tennō, 11 km away.
Topography around Oga
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Oga.
Within 3 km, the terrain around Oga has only modest variations in elevation — a maximum elevation change of 112 m around an average of 15 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 713 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,449 m.
The land around Oga is covered by water (61%) and trees (27%) within 3 km, water (65%) and trees (22%) within 16 km, and trees (46%) and water (45%) 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 Oga (39.871°, 139.8493°, elevation 6 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.