Karuizawa in September
6.1out of 10
Possible, with caveats
Warm and comfortable: highs around 22°C. Very wet: about 20 rainy days.
22°CAvg high
16°CAvg low
20Rainy days (244 mm)
12:13 hDaylight
05:33Sunrise · 17:46 Sunset
Why this score
- Warm and comfortable: highs around 22°C
- Very wet: about 20 rainy days
- Rain varies a lot between years (±4.4 days)
What to wear and pack
- T-shirts and light layers
- Rain jacket or compact umbrella
How reliable is the forecast?
Rain in September varies a lot between years (±4.4 rainy days), so check the forecast closer to your trip. Averages cover 30 years (1991–2020). Individual days can differ a lot.
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 3°C | -4°C | 60 mm | 7 | – | – | 4.6 |
| February | 4°C | -4°C | 64 mm | 9 | – | – | 4.6 |
| March | 8°C | -1°C | 107 mm | 13 | – | – | 4.8 |
| April | 14°C | 5°C | 122 mm | 13 | – | – | 5.9 |
| May | 19°C | 10°C | 166 mm | 17 | – | – | 6.0 |
| June | 22°C | 15°C | 256 mm | 23 | – | – | 6.0 |
| July | 26°C | 19°C | 279 mm | 24 | – | – | 6.1 |
| August | 26°C | 19°C | 242 mm | 24 | – | – | 6.1 |
| September | 22°C | 16°C | 244 mm | 20 | – | – | 6.1 |
| October | 17°C | 9°C | 192 mm | 14 | – | – | 5.8 |
| November | 12°C | 3°C | 70 mm | 9 | – | – | 6.3 |
| December | 6°C | -1°C | 48 mm | 8 | – | – | 5.3 |
Frequently asked questions
How hot is Karuizawa in September?
Daytime highs average 22°C and nights about 16°C.
When is the best time to visit Karuizawa?
The best months are November, July, August, September.