Best time to visit Karuizawa
Month-by-month weather averages for Karuizawa.
Karuizawa, Nagano, Japan
°C
mm
- Average daily high and low
- Precipitation
- Good month
- Best month
- Made good or best by an event
| Month | Average daily high | Average daily low | Precipitation | Verdict |
|---|---|---|---|---|
| January | 3.5 °C / 38 °F | -3.9 °C / 25 °F | 47 mm / 1.8 in | neither best nor good |
| February | 4.9 °C / 41 °F | -3.6 °C / 26 °F | 66 mm / 2.6 in | neither best nor good |
| March | 9.3 °C / 49 °F | -0.8 °C / 31 °F | 103 mm / 4.1 in | neither best nor good |
| April | 14.8 °C / 59 °F | 4 °C / 39 °F | 110 mm / 4.3 in | good month |
| May | 20 °C / 68 °F | 9.6 °C / 49 °F | 138 mm / 5.4 in | good month |
| June | 22.6 °C / 73 °F | 14.3 °C / 58 °F | 194 mm / 7.6 in | neither best nor good |
| July | 26.3 °C / 79 °F | 18.7 °C / 66 °F | 232 mm / 9.1 in | neither best nor good |
| August | 27.7 °C / 82 °F | 19.5 °C / 67 °F | 177 mm / 7 in | neither best nor good |
| September | 23.4 °C / 74 °F | 15.6 °C / 60 °F | 180 mm / 7.1 in | good month |
| October | 17.2 °C / 63 °F | 9 °C / 48 °F | 160 mm / 6.3 in | good month |
| November | 11.7 °C / 53 °F | 2.6 °C / 37 °F | 65 mm / 2.5 in | neither best nor good |
| December | 6 °C / 43 °F | -1.9 °C / 29 °F | 53 mm / 2.1 in | neither best nor good |
Good and best months depend on more than temperature, rain and events. How they are chosen
Each activity on this page has its own good and best months, rated on twenty years of daily weather records. Which measures count, and how much, depends on the activity: humidity for exploring outdoors, wind for the beach, hiking and skiing, snow for skiing alone. Between them, the activities are rated on:
- Daytime highs
- Night-time lows
- How warm it feels
- Humidity
- How much of the day is sunny
- Hours of daylight
- Monthly rainfall
- How many days it rains
- Days of heavy rain
- Wind
- Snowfall and days with snow
- Major events, such as festivals
The chart shows the good and best months for exploring outdoors.
The event icon marks a month that an event lifts to good or best, such as a festival or a natural spectacle. Choose “Weather only” in the toolbar to rate the months on weather alone.
Best months by activity
Exploring outdoors
Mild days and nights, mostly dry and bright. The default for 'when should I go'.
- JJanuary: neither
- FFebruary: neither
- MMarch: neither
- AApril: good
- MMay: good
- JJune: neither
- JJuly: neither
- AAugust: neither
- SSeptember: good
- OOctober: good
- NNovember: neither
- DDecember: neither
- Good
- April–May, September–October
Why these months
April · good
In its favour: share of daylight that is sunny 72%, average daily high 14.8 °C / 59 °F, precipitation 110 mm / 4.3 in, relative humidity 60%, days with heavy rain 3.4 days, average daily low 4 °C / 39 °F.
Against: feels like (high) 12.2 °C / 54 °F, wet days 12.8 days.
May · good
In its favour: feels like (high) 18.8 °C / 66 °F, average daily high 20 °C / 68 °F, share of daylight that is sunny 69%, relative humidity 62%, average daily low 9.6 °C / 49 °F, days with heavy rain 4.2 days.
Against: precipitation 138 mm / 5.4 in, wet days 14.8 days.
September · good
In its favour: feels like (high) 24.6 °C / 76 °F, average daily high 23.4 °C / 74 °F, share of daylight that is sunny 68%, average daily low 15.6 °C / 60 °F.
Against: precipitation 180 mm / 7.1 in, wet days 17.9 days, days with heavy rain 5.4 days, relative humidity 78%.
October · good
In its favour: feels like (high) 16 °C / 61 °F, share of daylight that is sunny 69%, average daily high 17.2 °C / 63 °F, average daily low 9 °C / 48 °F, days with heavy rain 4.2 days, relative humidity 76%.
Against: precipitation 160 mm / 6.3 in, wet days 13.6 days.
An activity is listed only where it applies: skiing at ski destinations, beach and swimming at beach destinations. The nearest ski area is 鹿沢スノーエリア, Kazawa Snow Area, 19 km away.
Weather averages
Monthly averages over twenty years, 2006–2025. Highs, lows and precipitation are in the chart at the top.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels like (high) | -1.2 °C | 0.5 °C | 5.6 °C | 12.2 °C | 18.8 °C | 23.2 °C | 28.9 °C | 30.6 °C | 24.6 °C | 16 °C | 8.7 °C | 1.8 °C |
| Days with heavy rain | 1.4 days | 2.1 days | 3.6 days | 3.4 days | 4.2 days | 6.8 days | 7.9 days | 5.7 days | 5.4 days | 4.2 days | 2.2 days | 1.9 days |
| Time rain usually falls | 2 pm | 7 am | 2 pm | 4 pm | 2 pm | 3 pm | 3 pm | 3 pm | 2 pm | 4 pm | 4 pm | 4 am |
| Sunshine per day | 8.7 h | 8.7 h | 9.3 h | 9.5 h | 9.7 h | 9.2 h | 9.1 h | 10.1 h | 8.4 h | 7.8 h | 7.8 h | 8 h |
| Relative humidity | 56% | 57% | 58% | 60% | 62% | 72% | 77% | 75% | 78% | 76% | 71% | 63% |
Air quality
Averaged over a shorter period (2022–2025) than the twenty-year averages above, and not counted towards good or best months.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Air pollution (PM2.5) 2022–2025 | 6.5 µg/m³ | 8.2 µg/m³ | 13.3 µg/m³ | 16.2 µg/m³ | 14.9 µg/m³ | 18.3 µg/m³ | 16.6 µg/m³ | 14.2 µg/m³ | 11.5 µg/m³ | 8.3 µg/m³ | 8.1 µg/m³ | 6.3 µg/m³ |
| Air pollution (PM2.5, daily peak) 2022–2025 | 12.6 µg/m³ | 15.8 µg/m³ | 24 µg/m³ | 28.8 µg/m³ | 25.7 µg/m³ | 32.3 µg/m³ | 29.6 µg/m³ | 24.6 µg/m³ | 21.5 µg/m³ | 14.8 µg/m³ | 15.3 µg/m³ | 13.2 µg/m³ |
- Good 15 µg/m³ or less
- Fair 15 to 25 µg/m³
- Moderate 25 to 37.5 µg/m³
- Poor 37.5 to 50 µg/m³
- Very poor 50 to 75 µg/m³
- Extremely poor over 75 µg/m³
Each figure is compared with the World Health Organization's guideline for a day's air, 15 µg/m³ or less, and with its interim targets above that. The words are ours: the WHO does not name its steps. The figures are modelled monthly averages, so single days can be well above them. The daily peak is the average of each day's highest hour, shaded on the same scale.