Asso, Japan experiences average highs of 20°C (68°F) and lows of 15°C (59°F) throughout the year. Rainfall is frequent, averaging about 13 rainy days per month. Sunshine is abundant, averaging about 9 hours per day. Average highs have stayed broadly stable across the available records.
Asso, Japan Weather & Climate 2026
Monthly climate averages for Asso, Japan. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: Jun–Sep At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
5.8/10
Best: May, June, October, November
UV Index
5
Low
Temperature 20°C / 15°C
Feels Like 21°C / 15°C
Rainy Days 13
Rainfall 194 mm
Sunshine 9 h
Humidity 76%
Wind Speed 19 km/h
Dew Point 13°C
Snow Days 2 days
Hottest Month
30°C
August
Avg Low 26°C
Rain 18 days
Coldest Month
6°C
January
Avg High 10°C
Rain 9 days
Driest Month
8 days
November
Avg High 18°C
Avg Low 13°C
Windiest Month
23 km/h
January (Gusts 49)
Sea Temperature
16°C – 29°C
Warmest water: August (
28.5°C
)
Worst Time to Visit
Consider avoiding July, August due to heavy rainfall, oppressive humidity.
Sun Position
Sunrise 04:59
Daylight 14.2h
Sunset 19:10
Live conditions —
Asso on the map · live conditions
Asso, Japan
- Continent
- Asia
- Country
- Japan
- City
- Asso
- Population
- 15.2K
- Coordinates
- 33.70°, 135.42°
Seasonal Breakdown
Spring
Mar–May
Avg High 18°C
Avg Low 13°C
Rain 12 days/mo
1/3 best months
Summer
Jun–Aug
Avg High 28°C
Avg Low 23°C
Rain 17 days/mo
1/3 best months
Autumn
Sep–Nov
Avg High 23°C
Avg Low 18°C
Rain 13 days/mo
2/3 best months
Winter
Dec–Feb
Avg High 11°C
Avg Low 6°C
Rain 9 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
High Low Shaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 10°C / 6°C . Feb: 11°C / 6°C . Mar: 15°C / 9°C . Apr: 19°C / 13°C . May: 22°C / 16°C . Jun: 25°C / 20°C . Jul: 29°C / 25°C . Aug: 30°C / 26°C . Sep: 28°C / 23°C . Oct: 23°C / 18°C . Nov: 18°C / 13°C . Dec: 12°C / 8°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 82 mm. Feb: 106 mm. Mar: 158 mm. Apr: 184 mm. May: 250 mm. Jun: 357 mm. Jul: 295 mm. Aug: 241 mm. Sep: 237 mm. Oct: 233 mm. Nov: 103 mm. Dec: 77 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 67%. Feb: 67%. Mar: 71%. Apr: 74%. May: 78%. Jun: 84%. Jul: 87%. Aug: 84%. Sep: 82%. Oct: 75%. Nov: 71%. Dec: 68%.
Monthly Wind Speed
Wind Speed Gusts
Bar chart showing monthly wind speed. Jan: 23 km/h . Feb: 23 km/h . Mar: 21 km/h . Apr: 20 km/h . May: 18 km/h . Jun: 17 km/h . Jul: 16 km/h . Aug: 16 km/h . Sep: 17 km/h . Oct: 18 km/h . Nov: 19 km/h . Dec: 22 km/h .
Sunshine
Sunshine
Sunshine: Jan: 8h. Feb: 8h. Mar: 9h. Apr: 9h. May: 9h. Jun: 9h. Jul: 10h. Aug: 11h. Sep: 9h. Oct: 8h. Nov: 8h. Dec: 8h.
Sea Temperature
Sea Temperature swim
Line chart showing monthly sea temperature. Jan: 16°C . Feb: 16°C . Mar: 16°C . Apr: 18°C . May: 20°C . Jun: 23°C . Jul: 27°C . Aug: 29°C . Sep: 28°C . Oct: 26°C . Nov: 22°C . Dec: 19°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 4. Feb: UV 4. Mar: UV 5. Apr: UV 6. May: UV 6. Jun: UV 6. Jul: UV 8. Aug: UV 7. Sep: UV 6. Oct: UV 5. Nov: UV 4. Dec: UV 3.
Monthly Daylight Hours
Daylight 12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy
Snow Days
Snow Days Snowfall
Snow Days: Jan: 3 days. Feb: 2 days. Mar: 0 days. Apr: 0 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 0 days. Nov: 0 days. Dec: 1 days.
Climate Trends
Average highs have stayed broadly stable across the available records. Average rainfall is trending drier by about 40 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Aug 2025 · 30°C | Aug · 30°C |
| Coldest month | Feb 2025 · 4°C | Jan · 6°C |
| Wettest month | May 2025 · 347 mm | Jun · 357 mm |
| Windiest month | Feb 2025 · 25 km/h | Jan · 23 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Fair April
Wet May best
Excellent June best
Excellent July
Wet August
Wet September
Wet October best
Excellent November best
Good December
Fair | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 10°C / 6°C | 6°C / 1°C | 9days (82 mm) Wet | 8h Good | 67% Muggy | 3.5 Moderate | Poor | View Details |
| February | 11°C / 6°C | 7°C / 1°C | 9days (106 mm) Wet | 8.2h Good | 67% Muggy | 4.2 Moderate | Poor | View Details |
| March | 15°C / 9°C | 13°C / 6°C | 12days (158 mm) Wet | 8.6h Good | 71% Muggy | 5.2 High | Fair | View Details |
| April | 19°C / 13°C | 18°C / 11°C | 11days (184 mm) Wet | 9h Good | 74% Muggy | 5.8 High | Wet | View Details |
| May best | 22°C / 16°C | 23°C / 16°C | 12days (250 mm) Wet | 8.9h Good | 78% Humid | 5.9 High | Excellent | View Details |
| June best | 25°C / 20°C | 28°C / 22°C | 17days (357 mm) Wet | 8.5h Good | 84% Humid | 6.3 High | Excellent | View Details |
| July | 29°C / 25°C | 34°C / 29°C | 17days (295 mm) Wet | 9.8h Good | 87% Very Muggy | 7.7 Very High | Wet | View Details |
| August | 30°C / 26°C | 36°C / 30°C | 18days (241 mm) Wet | 10.5h Excellent | 84% Humid | 7.3 Very High | Wet | View Details |
| September | 28°C / 23°C | 32°C / 26°C | 18days (237 mm) Wet | 8.9h Good | 82% Humid | 6.4 High | Wet | View Details |
| October best | 23°C / 18°C | 24°C / 18°C | 12days (233 mm) Wet | 7.8h Good | 75% Muggy | 4.7 Moderate | Excellent | View Details |
| November best | 18°C / 13°C | 16°C / 10°C | 8days (103 mm) Wet | 8h Good | 71% Muggy | 3.7 Moderate | Good | View Details |
| December | 12°C / 8°C | 9°C / 4°C | 9days (77 mm) Wet | 7.8h Good | 68% Muggy | 3.3 Moderate | Fair | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Asso are May, June, October, November, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Asso, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Asso is August, with average daytime highs of 30°C (86°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Asso is January, with average overnight lows of 6°C (42°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Asso is June, averaging 357mm of precipitation across 17 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Asso runs through August, September, June, July, with the heaviest rainfall in August. Based on 10-year averages for Asso.
Asso receives approximately 104 sunshine hours per year. The sunniest month is August with around 11 hours. Based on climate data for Asso.
The least favorable months to visit Asso are July, August, primarily due to heavy rainfall, oppressive humidity. For the best conditions, consider May, June, October, November instead.
The annual average UV index in Asso is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Asso is 76%, classified as humid. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in June, July, August, September, October, November average 26°C (79°F), which is warm and comfortable for swimming and water activities.
Yes, Asso receives snow. Months with snowfall average 2 snow days and 1 cm (0 in) of accumulation, with about 0 frost days during winter.
Average wind speeds in Asso are 19 km/h (12 mph). The windiest month is January with peak winds reaching 23 km/h (14 mph) (gusts up to 49 km/h / 30 mph).
Asso averages 4 clear-sky days per month with overall cloud cover around 58%. The clearest skies occur in November.
The annual average dew point in Asso is 13°C (55°F), which feels pleasant with low humidity. Outdoor activities are comfortable year-round from a humidity standpoint.
Asso 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 Asso ranges from 15°C (59°F) to 21°C (70°F) on average. The 'feels like' temperature closely matches the actual temperature throughout most of the year.
July is not the best time to visit Asso, with a climate score of 3.8/10. Consider visiting during May, June, October, November instead for better conditions.
For July in Asso, pack Umbrella, Waterproof jacket, Waterproof shoes, Breathable clothing, Sunscreen (SPF 30+). With average highs of 29°C (84°F) and 17 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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