When to go to Karuizawa, by the numbers
- Months with average highs between 15°C and 25°C and fewer than 10 wet days: May and October.
- Fewest wet days: December (5.0 days).
- Quietest hotels in 2025 (Nagano Prefecture): March (32.9%), April (33.3%) and December (33.3%).
- Busiest hotels in 2025 (Nagano Prefecture): August (51.2%), July (42.8%) and September (42.8%).
What to wear in Karuizawa, month by month
| Month | Level | Average high | Wet days |
|---|---|---|---|
| January | Freezing | 2.3°C | 5.2 days |
| February | Freezing | 3.5°C | 5.3 days |
| March | Cold | 7.8°C | 8.4 days |
| April | Chilly | 14.3°C | 8.9 days |
| May | Cool | 19.2°C | 9.9 days |
| June | Mild | 21.5°C | 12.6 days |
| July | Warm | 25.3°C | 14.8 days |
| August | Warm | 26.3°C | 11.5 days |
| September | Mild | 21.7°C | 11.4 days |
| October | Cool | 16.2°C | 9.3 days |
| November | Chilly | 11.2°C | 5.9 days |
| December | Cold | 5.3°C | 5.0 days |
How busy Karuizawa is, month by month
- Jan38.3%
- Feb41.8%
- Mar32.9%
- Apr33.3%
- May38.0%
- Jun33.8%
- Jul42.8%
- Aug51.2%
- Sep42.8%
- Oct42.4%
- Nov37.4%
- Dec33.3%
Frequently asked questions
When is the best time to visit Karuizawa?
Months with average highs between 15°C and 25°C and fewer than 10 wet days: May and October. Fewest wet days: December (5.0 days).
What is the hottest month in Karuizawa?
August has the highest average high, 26.3°C (79°F). January has the lowest, 2.3°C (36°F) (JMA, 1991–2020).
What is the rainiest month in Karuizawa?
September has the most precipitation (193.5 mm), and July has the most wet days (14.8 days) (JMA, 1991–2020).
Karuizawa weather month by month
Averages for 1991–2020 at the JMA's Karuizawa station (999 m above sea level). Months with their own page are linked; the others follow.
| Month | High | Low | Precipitation | Wet days | Sunshine |
|---|---|---|---|---|---|
| January | 2.3°C | −8.2°C | 36.8 mm | 5.2 days | 182 hours |
| February | 3.5°C | −8.0°C | 36.8 mm | 5.3 days | 192 hours |
| March | 7.8°C | −4.5°C | 68.3 mm | 8.4 days | 195 hours |
| April | 14.3°C | 0.6°C | 81.0 mm | 8.9 days | 205 hours |
| May | 19.2°C | 6.3°C | 108.8 mm | 9.9 days | 198 hours |
| June | 21.5°C | 11.8°C | 154.6 mm | 12.6 days | 145 hours |
| July | 25.3°C | 16.4°C | 191.8 mm | 14.8 days | 139 hours |
| August | 26.3°C | 17.1°C | 141.6 mm | 11.5 days | 163 hours |
| September | 21.7°C | 13.0°C | 193.5 mm | 11.4 days | 127 hours |
| October | 16.2°C | 6.3°C | 151.1 mm | 9.3 days | 140 hours |
| November | 11.2°C | −0.2°C | 52.5 mm | 5.9 days | 162 hours |
| December | 5.3°C | −5.3°C | 29.6 mm | 5.0 days | 172 hours |
- Jan2.3°C
- Feb3.5°C
- Mar7.8°C
- Apr14.3°C
- May19.2°C
- Jun21.5°C
- Jul25.3°C
- Aug26.3°C
- Sep21.7°C
- Oct16.2°C
- Nov11.2°C
- Dec5.3°C
Events in Karuizawa through the year
| Event | Month | When |
|---|---|---|
| Spring Bird Photography Workshop and Talk鳥の「まなざし」と出会う、春の野鳥撮影ワークショップ & トークセミナー | Apr | 25 April 2026 (one day) Official page |
| Christmas at Karuizawa Hoshino Areaやどりぎが灯る温かな街並み～軽井沢星野エリアのクリスマス | Nov and Dec | From late November to 25 December (2025: 22 November to 25 December) Official page |
| Hoshifuru Mori no Christmas at Karuizawa Kogen Church軽井沢高原教会 星降る森のクリスマス | Nov and Dec | From the end of November to 25 December (2025: 30 November to 25 December) Official page |
Read more
Sources for this page
- Normals for 1991–2020: Karuizawa (軽井沢), month by month (平年値 年・月ごとの値)Japan Meteorological Agency (JMA)
- Normals for 1991–2020: Karuizawa (軽井沢), 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
- Spring Bird Photography Workshop and Talk (鳥の「まなざし」と出会う、春の野鳥撮影ワークショップ & トークセミナー)Karuizawa Hoshino Area (Hoshino Resorts)
- Christmas at Karuizawa Hoshino Area (やどりぎが灯る温かな街並み～軽井沢星野エリアのクリスマス)Karuizawa Hoshino Area (Hoshino Resorts)