Temperature records for Suwa (Nagano)
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Temperatures over the 3 months before and after
The gray bands show the range that the high (upper band) and the low (lower band) fell within on each day over the 30 years 1996–2025 (between the 10th and 90th percentiles, so about 80% of the 30 years fall within it). The shading between the solid and dashed lines marks days when the high was above normal (warm colors) or below normal (cool colors).
Show the values by date
| Date | Observed high | Observed low | Normal high | Normal low | Range of highs | Range of lows |
|---|---|---|---|---|---|---|
| Aug 1 | 33.2°C | 22.4°C | 30.1°C | 20.7°C | ||
| Sep 1 | 31.5°C | 21.7°C | 27.6°C | 19.0°C | ||
| Oct 1 | 24.3°C | 14.7°C | 21.3°C | 12.7°C | ||
| ― | ||||||
| Dec 1 | 9.7°C | 0.3°C | 6.5–12.7°C | -3.1–3.8°C | ||
| Jan 1 | 4.7°C | -4.6°C | 1.0–8.5°C | -8.3–-2.5°C | ||
| Jan 31 | 3.7°C | -6.1°C | 0.9–7.9°C | -9.4–-1.7°C |
These are statistics compiled from observations for 1996–2025 (30 years), not a weather forecast for any particular day. For the latest forecasts, see the JMA website.
― on the normal curve
Monthly normals for Suwa
Temperature (monthly normals)
The lines show monthly normals: the upper line is the monthly mean of the daily high and the lower line the monthly mean of the daily low, and the middle line is the monthly mean temperature. Touch the point for a month to read its values. Normals are the 1991–2020 average.
Precipitation (monthly normals, mm)
Table of monthly normals
| Month | Mean | High | Low | Precipitation |
|---|---|---|---|---|
| Jan | -1.1 | 3.8 | -5.5 | 43.3 |
| Feb | -0.2 | 5.1 | -5.0 | 50.6 |
| Mar | 4.0 | 9.8 | -1.0 | 89.0 |
| Apr | 10.0 | 16.1 | 4.4 | 92.8 |
| May | 15.5 | 21.5 | 10.2 | 111.7 |
| Jun | 19.3 | 24.5 | 15.2 | 155.1 |
| Jul | 23.2 | 28.2 | 19.6 | 194.0 |
| Aug | 24.1 | 29.5 | 20.3 | 140.8 |
| Sep | 19.8 | 24.7 | 16.2 | 176.9 |
| Oct | 13.4 | 18.5 | 9.4 | 136.8 |
| Nov | 7.3 | 12.7 | 2.7 | 69.0 |
| Dec | 1.9 | 6.8 | -2.4 | 41.6 |
Temperatures are in degrees Celsius (°C) and precipitation in mm. Blank cells have no normal.
Annual mean temperature (1996–2025)
The yearly average of the daily mean temperature (the line is broken in years with many missing values). This station's observing conditions changed on March 21, 2000; October 22, 2003; December 4, 2007; June 25, 2008 (for example, a relocation or new instruments), so the statistics may not be continuous across those dates.
The normals listed here are averages over the 30 years from 1991 to 2020. They are fixed values that stay the same until the next revision of the normals, and they show how warm or cold that month usually is in that area.
All-time records
Records are statistics as of November 1, 2026. The statistical period differs by element, depending on when observations began or the station moved.
| Record | Value | Date | Records began |
|---|---|---|---|
| Highest temperature | 35.5°C | Aug 20, 1995 | Jan 1945 |
| Lowest temperature | -23.1°C | Feb 18, 1947 | Jan 1945 |
| Highest daily minimum | 24.6°C | Jul 24, 2026 | Jan 1945 |
| Lowest daily maximum | -6.4°C | Feb 3, 1947 | Jan 1945 |
| Heaviest daily rainfall | 161.5 mm | Sep 28, 1983 | Jan 1945 |
Top 5 highest temperatures
| Rank | Value | Date |
|---|---|---|
| 1 | 35.5°C | Aug 20, 1995 |
| 2 | 35.5°C | Aug 15, 1994 |
| 3 | 35.4°C | Jul 22, 2026 |
| 4 | 35.3°C | Aug 8, 1994 |
| 5 | 35.3°C | Aug 13, 1947 |
12-month dry-day calendar
The dry-day rate is the share of years with no precipitation (rain or snow) of 1 mm or more on that day (daily precipitation under 1 mm, smoothed over 4 days either side). It is based on observations for 1996–2025 (30 years).
The deeper the amber, the more years that day stayed dry (the legend above shows the colors). Each row ends with the monthly average; detailed values are in the monthly table below.
Monthly averages through the year
How the monthly average dry-day rate changes over the 12 months (the axis fits the range of values). The values match the monthly table below.
Monthly table of dry-day rates and climate
| Month | Dry-day rate | 2 days in a row | 3 days in a row | Windy days | Sunshine (avg.) | High (avg.) | Low (avg.) | Comfort |
|---|---|---|---|---|---|---|---|---|
| Jan | 84.6% | 73.6% | 63.6% | 10.7% | 6.0 h | 3.8°C | -5.4°C | Tough |
| Feb | 79.4% | 64.6% | 52.4% | 16.5% | 6.3 h | 5.3°C | -4.8°C | Harsh |
| Mar | 73.3% | 55.8% | 41.6% | 20.4% | 6.6 h | 10.2°C | -0.7°C | Fair |
| Apr | 70.3% | 52.1% | 38.0% | 18.1% | 6.9 h | 16.3°C | 4.7°C | Comfortable |
| May | 69.9% | 51.9% | 37.1% | 11.1% | 6.9 h | 21.6°C | 10.4°C | Comfortable |
| Jun | 59.8% | 40.3% | 26.0% | 4.2% | 5.6 h | 24.8°C | 15.4°C | Comfortable |
| Jul | 57.1% | 39.0% | 27.8% | 1.1% | 5.7 h | 28.5°C | 19.8°C | Good |
| Aug | 65.0% | 47.1% | 35.0% | 2.6% | 6.5 h | 29.6°C | 20.6°C | Good |
| Sep | 63.9% | 47.4% | 35.5% | 6.8% | 5.2 h | 25.1°C | 16.7°C | Comfortable |
| Oct | 72.6% | 57.6% | 45.0% | 8.3% | 5.3 h | 18.6°C | 9.5°C | Comfortable |
| Nov | 78.9% | 64.4% | 51.4% | 8.4% | 5.6 h | 12.8°C | 3.0°C | Good |
| Dec | 84.0% | 72.7% | 63.2% | 7.9% | 5.6 h | 6.8°C | -2.2°C | Tough |
"2 days in a row" and "3 days in a row" are the monthly averages of the share of years in which it stayed dry for 2 or 3 days from that day (counted from the actual consecutive records). "Windy days" is the share of days with a daily mean wind speed of 5 m/s or more. Sunshine averages include estimates from March 2021 onward at some stations. The month names link to monthly pages that compare stations across Japan.
Comfort over the 12 months
A guide that rates the comfort of each month on 5 levels from observations of dry-day rate, sunshine, wind, and temperature for 1996–2025 (30 years). The levels are also in the monthly table above.
This station's observing conditions changed on March 21, 2000; October 22, 2003; December 4, 2007; June 25, 2008 (for example, a relocation or new instruments), so the statistics may not be continuous across those dates.
These are statistics compiled from observations for 1996–2025 (30 years), not a weather forecast for any particular day. For the latest forecasts, see the JMA website.
About the Suwa station
This staffed weather station is at an elevation of 760 m on the shore of Lake Suwa, and its statistics run from January 1945. The record low is -23.1°C on February 18, 1947; -22.4°C followed on the next day, the 19th, and -23.0°C was observed on February 28, 1981. On February 3, 1947, the daytime high reached only -6.4°C.
Summer is held down by the elevation, and the record high of 35.5°C is shared by 2 days, August 20, 1995, and August 15, 1994. The normal maximum on August 3, the warmest day in the normals, is 30.3°C, nearly 2°C below the 32.2°C at Matsumoto, also in Nagano Prefecture. The daily rainfall record is 161.5 mm on September 28, 1983, and on the same day Iijima in the Ina Valley observed 322.0 mm.
Record values in this description are based on data collected as of September 2026.
Compare and explore
Nearby stations: Matsumoto-Imai (about 22 km) / Matsumoto (about 26 km) / Tateshina (about 31 km)
Compare with Tokyo in Head-to-head
Stations in Nagano / Today's national rankings / Trip planning calendar / Pressure changes at Suwa