When to go to Kusatsu Onsen, by the numbers
- No month has average highs between 15°C and 25°C with fewer than 10 wet days.
- Fewest wet days: November (8.2 days).
- Quietest hotels in 2025 (Gunma Prefecture): January (41.2%), December (43.4%) and April (43.8%).
- Busiest hotels in 2025 (Gunma Prefecture): August (55.2%), October (49.2%) and July (48.9%).
What to wear in Kusatsu Onsen, month by month
| Month | Level | Average high | Wet days |
|---|---|---|---|
| January | Freezing | −0.4°C | 11.6 days |
| February | Freezing | 0.7°C | 10.7 days |
| March | Freezing | 4.7°C | 11.5 days |
| April | Chilly | 11.5°C | 11.0 days |
| May | Cool | 17.0°C | 12.2 days |
| June | Cool | 19.6°C | 15.8 days |
| July | Mild | 23.4°C | 18.2 days |
| August | Mild | 24.2°C | 16.2 days |
| September | Cool | 19.8°C | 14.4 days |
| October | Chilly | 14.5°C | 11.1 days |
| November | Cold | 9.1°C | 8.2 days |
| December | Freezing | 2.9°C | 10.9 days |
How busy Kusatsu Onsen is, month by month
- Jan41.2%
- Feb45.5%
- Mar44.9%
- Apr43.8%
- May46.4%
- Jun46.5%
- Jul48.9%
- Aug55.2%
- Sep47.8%
- Oct49.2%
- Nov48.0%
- Dec43.4%
Frequently asked questions
When is the best time to visit Kusatsu Onsen?
No month has average highs between 15°C and 25°C with fewer than 10 wet days. Fewest wet days: November (8.2 days).
What is the hottest month in Kusatsu Onsen?
August has the highest average high, 24.2°C (76°F). January has the lowest, −0.4°C (31°F) (JMA, 1991–2020).
What is the rainiest month in Kusatsu Onsen?
July has the most precipitation (263.5 mm), and July has the most wet days (18.2 days) (JMA, 1991–2020).
Kusatsu Onsen weather month by month
Averages for 1991–2020 at the JMA's Kusatsu station (1,223 m above sea level). Months with their own page are linked; the others follow.
| Month | High | Low | Precipitation | Wet days | Sunshine |
|---|---|---|---|---|---|
| January | −0.4°C | −7.8°C | 68.5 mm | 11.6 days | 153 hours |
| February | 0.7°C | −7.8°C | 66.1 mm | 10.7 days | 148 hours |
| March | 4.7°C | −4.5°C | 90.6 mm | 11.5 days | 182 hours |
| April | 11.5°C | 1.1°C | 106.2 mm | 11.0 days | 192 hours |
| May | 17.0°C | 6.5°C | 150.7 mm | 12.2 days | 189 hours |
| June | 19.6°C | 11.1°C | 218.3 mm | 15.8 days | 120 hours |
| July | 23.4°C | 15.5°C | 263.5 mm | 18.2 days | 118 hours |
| August | 24.2°C | 16.2°C | 236.8 mm | 16.2 days | 134 hours |
| September | 19.8°C | 12.3°C | 254.6 mm | 14.4 days | 109 hours |
| October | 14.5°C | 6.0°C | 162.5 mm | 11.1 days | 133 hours |
| November | 9.1°C | 0.4°C | 63.9 mm | 8.2 days | 161 hours |
| December | 2.9°C | −4.8°C | 60.4 mm | 10.9 days | 162 hours |
- Jan−0.4°C
- Feb0.7°C
- Mar4.7°C
- Apr11.5°C
- May17.0°C
- Jun19.6°C
- Jul23.4°C
- Aug24.2°C
- Sep19.8°C
- Oct14.5°C
- Nov9.1°C
- Dec2.9°C
Events in Kusatsu Onsen through the year
| Event | Month | When |
|---|---|---|
| Michi-no-Eki Autumn Leaves Light-up道の駅紅葉ライトアップ | Oct and Nov | From late October to mid-November (2026: 28 October to 15 November) Official page |
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Sources for this page
- Normals for 1991–2020: Kusatsu (草津), month by month (平年値 年・月ごとの値)Japan Meteorological Agency (JMA)
- Normals for 1991–2020: Kusatsu (草津), rain days, temperature days and snow (詳細)Japan Meteorological Agency (JMA)
- Overnight Travel Statistics Survey, 2025 final figures (宿泊旅行統計調査 2025年 年の確定値)Japan Tourism Agency
- Michi-no-Eki Autumn Leaves Light-up (道の駅紅葉ライトアップ)Kusatsu Onsen Tourism Association