Jōetsu climate
Jōetsu (Japan) has a humid subtropical climate (Köppen Cfa). The average temperature over the year is 15 °C58 °F, and about 1,812 mm71 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Jōetsu climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 541 | 033 | 337 | 1867.3 |
| Feb | 642 | 032 | 337 | 1144.5 |
| Mar | 949 | 337 | 643 | 1164.6 |
| Apr | 1661 | 745 | 1253 | 953.7 |
| May | 2271 | 1356 | 1864 | 923.6 |
| Jun | 2578 | 1865 | 2271 | 1335.2 |
| Jul | 2984 | 2373 | 2679 | 2068.1 |
| Aug | 3087 | 2475 | 2781 | 1566.1 |
| Sep | 2680 | 2068 | 2374 | 1676.6 |
| Oct | 2169 | 1457 | 1763 | 1686.6 |
| Nov | 1558 | 847 | 1153 | 1656.5 |
| Dec | 847 | 338 | 643 | 2158.5 |
| Year | 3087 | 032 | 1558 | 1,81271 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 90% | 91% | 1.5 | 9:52 |
| Feb | 87% | 86% | 2.3 | 10:46 |
| Mar | 82% | 79% | 3.5 | 11:51 |
| Apr | 77% | 70% | 4.5 | 13:06 |
| May | 77% | 68% | 5.3 | 14:09 |
| Jun | 81% | 76% | 5.1 | 14:42 |
| Jul | 84% | 79% | 4.7 | 14:28 |
| Aug | 82% | 70% | 4.9 | 13:34 |
| Sep | 83% | 74% | 3.9 | 12:22 |
| Oct | 82% | 71% | 2.9 | 11:10 |
| Nov | 84% | 77% | 1.9 | 10:07 |
| Dec | 88% | 87% | 1.4 | 9:37 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Jōetsu is like
The warmest month is August, with an average high of 30 °C87 °F and a low of 24 °C75 °F. The coldest is January, when highs average 5 °C41 °F and lows 0 °C33 °F. Seasons are strongly marked: the warmest month is on average 24.3 °C43.7 °F warmer than the coldest.
It is wet, with about 1,812 mm71 in of precipitation per year. The wettest three-month stretch is November–January, which brings 31% of the annual total. The wettest month is December (215 mm8.5 in), the driest is May (92 mm3.6 in).
Relative humidity ranges from 77% in May to 90% in January. The clearest skies (lowest average cloud amount, 68%) are typical of May. Average wind speed near the ground ranges from 5 km/h (3 mph) in July to 14 km/h (9 mph) in January. Daylight lasts from about 9.6 hours in December to 14.7 hours in June.
Best time to visit Jōetsu
Based on these averages, the most comfortable months for sightseeing and outdoor activities are May: average highs of 22 °C71 °F to 22 °C71 °F with 92 mm3.6 in to 92 mm3.6 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of 5 °C41 °F and very wet (186 mm7.3 in).
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Jōetsu
- Winter (December–February) — highs 541 to 8 °C47 °F, lows 032 to 3 °C38 °F, about 172 mm6.8 in of precipitation a month. Pack a warm coat, layers and closed shoes and an umbrella or light rain jacket.
- Spring (March–May) — highs 949 to 22 °C71 °F, lows 337 to 13 °C56 °F, about 101 mm4.0 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket and an umbrella or light rain jacket.
- Summer (June–August) — highs 2578 to 30 °C87 °F, lows 1865 to 24 °C75 °F, about 165 mm6.5 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and an umbrella or light rain jacket.
- Autumn (September–November) — highs 1558 to 26 °C80 °F, lows 847 to 20 °C68 °F, about 167 mm6.6 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an umbrella or light rain jacket.
How Jōetsu compares
Compared with Nagano, about 56 km to the south, Jōetsu is on average 2.1 °C3.7 °F warmer and receives 24% more precipitation (1,812 mm71 in vs 1,462 mm58 in). The difference is largest in January (4.1 °C7.3 °F warmer).
Of the 111 places in Japan covered by World Climates, Jōetsu is the 71st warmest by annual mean temperature and the 36th wettest by annual precipitation. See all of them on the Japan climate page.
Places in other countries with the most similar temperature and rainfall pattern: Kutaisi (Georgia, Cfa), Atlantic City (United States, Cfa) and Virginia Beach (United States, Cfa).
Nearby places
- Nagano 56 km · 12 °C54 °F · 1,462 mm58 in
- Nagaoka 64 km · 14 °C57 °F · 1,922 mm76 in
- Toyama 103 km · 15 °C59 °F · 1,810 mm71 in
- Matsumoto 105 km · 12 °C54 °F · 1,329 mm52 in
- Niigata 112 km · 15 °C58 °F · 1,702 mm67 in
- Maebashi 112 km · 14 °C57 °F · 1,469 mm58 in
- Takasaki 114 km · 14 °C58 °F · 1,434 mm56 in
- Takaoka 117 km · 15 °C59 °F · 2,104 mm83 in
Frequently asked questions
What is the warmest month in Jōetsu?
August is the warmest month in Jōetsu, with an average high of 30 °C (87 °F) and an average low of 24 °C (75 °F).
What is the coldest month in Jōetsu?
January is the coldest month, with an average high of 5 °C (41 °F) and an average low of 0 °C (33 °F).
When does it rain the most in Jōetsu?
December is the wettest month with about 215 mm (8.5 in) of precipitation; May is the driest with about 92 mm (3.6 in).
What is the best time to visit Jōetsu?
Judging by long-term averages, the most comfortable months are May.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 496 m, while Jōetsu lies at about 10 m. Temperatures on this page were therefore adjusted by +3.2 °C5.7 °F using the standard lapse rate of 6.5 °C per 1,000 m.