Oga, Japan experiences average highs of 15°C (59°F) and lows of 11°C (52°F) throughout the year. Rainfall is frequent, averaging about 16 rainy days per month. Average highs have warmed by 0.8°C (1.4°F) across the available records.
Oga, Japan Weather & Climate 2026
Monthly climate averages for Oga, Japan. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Mar–Oct 
Wetter season: Jan–Dec At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
4.8/10
Best: May, June, July, September
UV Index
5
Low
Temperature 15°C / 11°C
Feels Like 14°C / 9°C
Rainy Days 16
Rainfall 146 mm
Sunshine 8 h
Humidity 75%
Wind Speed 23 km/h
Dew Point 9°C
Snow Days 11 days
Frost Days 8 days
Hottest Month
27°C
August
Avg Low24°C
Rain15days
Coldest Month
0°C
January
Avg High3°C
Rain21days
Driest Month
12days
June
Avg High21°C
Avg Low17°C
Windiest Month
29 km/h
December (Gusts 51)
Sea Temperature
9°C – 28°C
Warmest water: August (
28.4°C
)
Worst Time to Visit
Consider avoiding January, February, March, December due to very cold temperatures, heavy rainfall.
Sun Position
Sunrise 04:13
Daylight 15h
Sunset 19:12
Live conditions—
Oga on the map · live conditions
Oga, Japan
- Continent
- Asia
- Country
- Japan
- City
- Oga
- Population
- 25.2K
- Coordinates
- 39.87°, 139.85°
Seasonal Breakdown
Spring
Mar–May
Avg High 12°C
Avg Low 8°C
Rain 14 days/mo
1/3 best months
Summer
Jun–Aug
Avg High 25°C
Avg Low 21°C
Rain 14 days/mo
2/3 best months
Autumn
Sep–Nov
Avg High 18°C
Avg Low 14°C
Rain 15 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 4°C
Avg Low 1°C
Rain 22 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 3°C / 0°C . Feb: 4°C / 1°C . Mar: 7°C / 4°C . Apr: 12°C / 8°C . May: 17°C / 13°C . Jun: 21°C / 17°C . Jul: 26°C / 22°C . Aug: 27°C / 24°C . Sep: 24°C / 21°C . Oct: 18°C / 14°C . Nov: 12°C / 8°C . Dec: 6°C / 3°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 109 mm. Feb: 98 mm. Mar: 99 mm. Apr: 116 mm. May: 124 mm. Jun: 145 mm. Jul: 174 mm. Aug: 221 mm. Sep: 172 mm. Oct: 164 mm. Nov: 160 mm. Dec: 170 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 71%. Feb: 70%. Mar: 69%. Apr: 74%. May: 79%. Jun: 83%. Jul: 85%. Aug: 81%. Sep: 75%. Oct: 69%. Nov: 68%. Dec: 71%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 27 km/h . Feb: 27 km/h . Mar: 25 km/h . Apr: 24 km/h . May: 21 km/h . Jun: 19 km/h . Jul: 17 km/h . Aug: 19 km/h . Sep: 19 km/h . Oct: 22 km/h . Nov: 25 km/h . Dec: 29 km/h .
Sunshine
Sunshine
Sunshine: Jan: 6h. Feb: 7h. Mar: 8h. Apr: 9h. May: 10h. Jun: 10h. Jul: 10h. Aug: 10h. Sep: 8h. Oct: 7h. Nov: 6h. Dec: 5h.
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 11°C . Feb: 9°C . Mar: 9°C . Apr: 11°C . May: 15°C . Jun: 20°C . Jul: 25°C . Aug: 28°C . Sep: 27°C . Oct: 23°C . Nov: 18°C . Dec: 14°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 2. Feb: UV 3. Mar: UV 4. Apr: UV 5. May: UV 6. Jun: UV 7. Jul: UV 7. Aug: UV 7. Sep: UV 5. Oct: UV 4. Nov: UV 3. Dec: UV 2.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 22 days. Feb: 18 days. Mar: 6 days. Apr: 1 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 0 days. Nov: 3 days. Dec: 17 days.
Climate Trends
Average highs have warmed by 0.8°C (1.4°F) across the available records. Average rainfall is trending wetter by about 31 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Aug 2025 · 28°C | Aug · 27°C |
| Coldest month | Feb 2025 · 1°C | Jan · 0°C |
| Wettest month | Aug 2025 · 315 mm | Aug · 221 mm |
| Windiest month | Feb 2025 · 32 km/h | Dec · 29 km/h |
Month-by-Month Weather Table
January
Wet 
February
Wet March
Poor April
Fair May best
Good June best
Excellent July best
Excellent August
Wet September best
Excellent October
Fair November
Wet December
Wet | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 3°C / 0°C | -1°C / -5°C | 21days (109 mm) Wet | 6.1h Fair | 71% Muggy | 2.1 Moderate | Wet | View Details |
| February | 4°C / 1°C | -1°C / -5°C | 19days (98 mm) Wet | 7.1h Good | 70% Muggy | 3.3 Moderate | Wet | View Details |
| March | 7°C / 4°C | 4°C / -1°C | 14days (99 mm) Wet | 8.3h Good | 69% Muggy | 4.3 Moderate | Poor | View Details |
| April | 12°C / 8°C | 9°C / 4°C | 14days (116 mm) Wet | 9h Good | 74% Muggy | 5.3 High | Fair | View Details |
| May best | 17°C / 13°C | 16°C / 11°C | 13days (124 mm) Wet | 9.5h Good | 79% Humid | 5.9 High | Good | View Details |
| June best | 21°C / 17°C | 23°C / 17°C | 12days (145 mm) Wet | 9.8h Good | 83% Humid | 6.6 High | Excellent | View Details |
| July best | 26°C / 22°C | 29°C / 25°C | 14days (174 mm) Wet | 9.5h Good | 85% Humid | 6.8 High | Excellent | View Details |
| August | 27°C / 24°C | 32°C / 27°C | 15days (221 mm) Wet | 9.6h Good | 81% Humid | 7 High | Wet | View Details |
| September best | 24°C / 21°C | 26°C / 21°C | 13days (172 mm) Wet | 8.4h Good | 75% Muggy | 5.4 High | Excellent | View Details |
| October | 18°C / 14°C | 16°C / 12°C | 14days (164 mm) Wet | 7.4h Good | 69% Muggy | 3.9 Moderate | Fair | View Details |
| November | 12°C / 8°C | 9°C / 4°C | 19days (160 mm) Wet | 6.2h Fair | 68% Muggy | 2.6 Moderate | Wet | View Details |
| December | 6°C / 3°C | 2°C / -3°C | 25days (170 mm) Wet | 5.4h Fair | 71% Muggy | 1.8 Low | Wet | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Oga are May, June, July, September, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Oga, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Oga is August, with average daytime highs of 27°C (81°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Oga is January, with average overnight lows of 0°C (33°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Oga is August, averaging 221mm of precipitation across 15 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Oga runs through December, January, February, November, with the heaviest rainfall in December. Based on 10-year averages for Oga.
Oga receives approximately 96 sunshine hours per year. The sunniest month is June with around 10 hours. Based on climate data for Oga.
The least favorable months to visit Oga are January, February, March, December, primarily due to very cold temperatures, heavy rainfall. For the best conditions, consider May, June, July, September instead.
The annual average UV index in Oga is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Oga is 75%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in July, August, September, October average 26°C (79°F), which is warm and comfortable for swimming and water activities.
Yes, Oga receives snow. Months with snowfall average 11 snow days and 20 cm (8 in) of accumulation, with about 8 frost days during winter.
Average wind speeds in Oga are 23 km/h (14 mph). The windiest month is December with peak winds reaching 29 km/h (18 mph) (gusts up to 51 km/h / 32 mph).
Oga averages 1 clear-sky days per month with overall cloud cover around 68%. The clearest skies occur in April.
The annual average dew point in Oga is 9°C (48°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Oga has a Humid Subtropical climate, classified as Cfa under the Köppen system. Temperate climates have mild winters and warm summers, with rainfall spread across the year and four distinct seasons.
The 'feels like' temperature in Oga ranges from 9°C (48°F) to 14°C (57°F) on average. The 'feels like' temperature closely matches the actual temperature throughout most of the year.
Yes, June is a great time to visit Oga. It earns a climate score of 8.1/10 with Excellent.
For June in Oga, pack Umbrella, Waterproof jacket, Sunscreen (SPF 30+), Sunglasses, Comfortable walking shoes. With average highs of 21°C (70°F) and 12 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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