Jōetsu, Japan experiences average highs of 17°C (63°F) and lows of 11°C (52°F) throughout the year. Rainfall is frequent, averaging about 19 rainy days per month. Average highs have stayed broadly stable across the available records.
Jōetsu, Japan Weather & Climate 2026
Monthly climate averages for Jōetsu, Japan. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Mar–Nov 
Wetter season: Jan–Dec At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
4.4/10
Best: April, May, June, September, October
UV Index
5
Low
Temperature 17°C / 11°C
Feels Like 18°C / 10°C
Rainy Days 19
Rainfall 197 mm
Sunshine 8 h
Humidity 82%
Wind Speed 12 km/h
Dew Point 11°C
Snow Days 14 days
Frost Days 11 days
Hottest Month
30°C
August
Avg Low 24°C
Rain 22 days
Coldest Month
0°C
January
Avg High 5°C
Rain 26 days
Driest Month
14 days
May
Avg High 22°C
Avg Low 13°C
Windiest Month
14 km/h
February (Gusts 45)
Sea Temperature
10°C – 29°C
Warmest water: August (
29.4°C
)
Worst Time to Visit
Consider avoiding January, February, August, December due to heavy rainfall.
Sun Position
Sunrise 04:39
Daylight 14.5h
Sunset 19:07
Live conditions —
Jōetsu on the map · live conditions
Jōetsu, Japan
- Continent
- Asia
- Country
- Japan
- City
- Jōetsu
- Population
- 189.4K
- Coordinates
- 37.15°, 138.24°
Seasonal Breakdown
Spring
Mar–May
Avg High 16°C
Avg Low 8°C
Rain 15 days/mo
2/3 best months
Summer
Jun–Aug
Avg High 28°C
Avg Low 21°C
Rain 20 days/mo
1/3 best months
Autumn
Sep–Nov
Avg High 20°C
Avg Low 14°C
Rain 18 days/mo
2/3 best months
Winter
Dec–Feb
Avg High 6°C
Avg Low 1°C
Rain 23 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: 5°C / 0°C . Feb: 5°C / 0°C . Mar: 10°C / 3°C . Apr: 16°C / 8°C . May: 22°C / 13°C . Jun: 25°C / 18°C . Jul: 29°C / 22°C . Aug: 30°C / 24°C . Sep: 26°C / 20°C . Oct: 20°C / 14°C . Nov: 14°C / 8°C . Dec: 8°C / 2°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 247 mm. Feb: 179 mm. Mar: 141 mm. Apr: 137 mm. May: 142 mm. Jun: 181 mm. Jul: 264 mm. Aug: 228 mm. Sep: 222 mm. Oct: 200 mm. Nov: 164 mm. Dec: 254 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 84%. Feb: 81%. Mar: 79%. Apr: 78%. May: 78%. Jun: 83%. Jul: 87%. Aug: 85%. Sep: 85%. Oct: 82%. Nov: 82%. Dec: 85%.
Monthly Wind Speed
Wind Speed Gusts
Bar chart showing monthly wind speed. Jan: 13 km/h . Feb: 14 km/h . Mar: 13 km/h . Apr: 13 km/h . May: 12 km/h . Jun: 10 km/h . Jul: 9 km/h . Aug: 10 km/h . Sep: 10 km/h . Oct: 12 km/h . Nov: 12 km/h . Dec: 13 km/h .
Sunshine
Sunshine
Sunshine: Jan: 7h. Feb: 8h. Mar: 8h. Apr: 9h. May: 10h. Jun: 10h. Jul: 9h. Aug: 10h. Sep: 8h. Oct: 7h. Nov: 7h. Dec: 7h.
Sea Temperature
Sea Temperature swim
Line chart showing monthly sea temperature. Jan: 12°C . Feb: 10°C . Mar: 10°C . Apr: 12°C . May: 16°C . Jun: 21°C . Jul: 26°C . Aug: 29°C . Sep: 28°C . Oct: 24°C . Nov: 19°C . Dec: 16°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 3. Feb: UV 4. Mar: UV 4. Apr: UV 6. May: UV 6. Jun: UV 7. Jul: UV 7. Aug: UV 7. Sep: UV 6. Oct: UV 4. Nov: UV 3. Dec: UV 2.
Monthly Daylight Hours
Daylight 12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy
Snow Days
Snow Days Snowfall
Snow Days: Jan: 26 days. Feb: 21 days. Mar: 13 days. Apr: 2 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 0 days. Nov: 4 days. Dec: 20 days.
Climate Trends
Average highs have stayed broadly stable across the available records. Average rainfall is trending wetter by about 13 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 31°C | Aug · 30°C |
| Coldest month | Feb 2025 · 0°C | Jan · 0°C |
| Wettest month | Aug 2025 · 339 mm | Jul · 264 mm |
| Windiest month | Feb 2025 · 15 km/h | Feb · 14 km/h |
Month-by-Month Weather Table
January
Wet 
February
Wet March
Poor April best
Good May best
Excellent June best
Excellent July
Wet August
Wet September best
Wet October best
Wet November
Wet December
Wet | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 5°C / 0°C | 2°C / -4°C | 26days (247 mm) Wet | 6.8h Fair | 84% Humid | 2.5 Moderate | Wet | View Details |
| February | 5°C / 0°C | 2°C / -4°C | 19days (179 mm) Wet | 7.8h Good | 81% Humid | 3.5 Moderate | Wet | View Details |
| March | 10°C / 3°C | 8°C / 0°C | 17days (141 mm) Wet | 8.4h Good | 79% Humid | 4.4 Moderate | Poor | View Details |
| April best | 16°C / 8°C | 16°C / 6°C | 15days (137 mm) Wet | 9.1h Good | 78% Humid | 5.8 High | Good | View Details |
| May best | 22°C / 13°C | 23°C / 12°C | 14days (142 mm) Wet | 9.5h Good | 78% Humid | 5.9 High | Excellent | View Details |
| June best | 25°C / 18°C | 28°C / 19°C | 17days (181 mm) Wet | 9.5h Good | 83% Humid | 6.5 High | Excellent | View Details |
| July | 29°C / 22°C | 35°C / 26°C | 22days (264 mm) Wet | 9.3h Good | 87% Very Muggy | 7.2 Very High | Wet | View Details |
| August | 30°C / 24°C | 36°C / 28°C | 22days (228 mm) Wet | 9.8h Good | 85% Humid | 7 High | Wet | View Details |
| September best | 26°C / 20°C | 30°C / 23°C | 20days (222 mm) Wet | 8h Good | 85% Humid | 5.5 High | Wet | View Details |
| October best | 20°C / 14°C | 20°C / 13°C | 17days (200 mm) Wet | 7.1h Good | 82% Humid | 3.8 Moderate | Wet | View Details |
| November | 14°C / 8°C | 13°C / 6°C | 18days (164 mm) Wet | 7.1h Good | 82% Humid | 2.9 Moderate | Wet | View Details |
| December | 8°C / 2°C | 5°C / -1°C | 24days (254 mm) Wet | 6.6h Fair | 85% Humid | 2.1 Moderate | Wet | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Jōetsu are April, May, June, September, October, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Jōetsu, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Jōetsu 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 Jōetsu is January, with average overnight lows of 0°C (32°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Jōetsu is July, averaging 264mm of precipitation across 22 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Jōetsu runs through January, December, July, August, with the heaviest rainfall in January. Based on 10-year averages for Jōetsu.
Jōetsu receives approximately 99 sunshine hours per year. The sunniest month is August with around 10 hours. Based on climate data for Jōetsu.
The least favorable months to visit Jōetsu are January, February, August, December, primarily due to heavy rainfall. For the best conditions, consider April, May, June, September, October instead.
The annual average UV index in Jōetsu is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Jōetsu is 82%, classified as humid. High humidity makes warm temperatures feel significantly hotter — lightweight, breathable clothing is recommended.
Yes — sea temperatures in July, August, September, October average 27°C (81°F), which is warm and comfortable for swimming and water activities.
Yes, Jōetsu receives snow. Months with snowfall average 14 snow days and 60 cm (24 in) of accumulation, with about 11 frost days during winter.
Average wind speeds in Jōetsu are 12 km/h (7 mph). The windiest month is February with peak winds reaching 14 km/h (8 mph) (gusts up to 45 km/h / 28 mph).
Jōetsu averages 2 clear-sky days per month with overall cloud cover around 70%. The clearest skies occur in May.
The annual average dew point in Jōetsu is 11°C (52°F), which feels pleasant with low humidity. Outdoor activities are comfortable year-round from a humidity standpoint.
Jōetsu 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 Jōetsu ranges from 10°C (50°F) to 18°C (64°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 Jōetsu, with a climate score of 4.1/10. Consider visiting during April, May, June, September, October instead for better conditions.
For July in Jōetsu, pack Umbrella, Waterproof jacket, Waterproof shoes, Breathable clothing, Sunscreen (SPF 30+). With average highs of 29°C (84°F) and 22 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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