Dry-day rate calendar for December
Period: observations for 1996–2025 (30 years)
This is the month when the winter pressure pattern appears and the gap between the Pacific side and the Sea of Japan side opens wide again. In the 1996–2025 records, dry-day rates at stations on the Pacific side reach some of the highest levels in the annual cycle, while snowy days continue on the Sea of Japan side.
The "dry-day rate" is the share of years in which a given day had no precipitation (rain or snow) of 1 mm or more (daily rainfall under 1 mm, smoothed over the 4 days before and after).
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.
December at a glance
The station with the highest monthly average dry-day rate in Japan, the national median, and the station with the lowest. The most comfortable stations this month: Saito / Takanabe / Hyuga (details in the comfort section below).
Dry-day rates across Japan (December average)
Each dot is 1 station. The highest and lowest stations are labeled on the map, and the top and bottom lists are below.
Daily calendar for major stations
The deeper the amber, the more years that day stayed dry (the colors match the legend above). The table below (averages for the early, middle, and late parts of the month) has the same values.
| Station | Early | Mid | Late | Monthly avg. | 2 days in a row | 3 days in a row | Windy days | Sunshine (avg.) |
|---|---|---|---|---|---|---|---|---|
| Sapporo | 51.5% | 50.7% | 45.2% | 49.0% | 28.0% | 17.4% | 7.9% | 2.8 hours |
| Sendai | 82.6% | 81.0% | 82.0% | 81.9% | 69.2% | 58.9% | 9.8% | 4.5 hours |
| Niigata | 26.1% | 28.6% | 33.2% | 29.4% | 10.6% | 3.5% | 25.6% | 1.9 hours |
| Kanazawa | 27.0% | 25.3% | 24.2% | 25.5% | 9.0% | 3.9% | 38.2% | 2.2 hours |
| Tokyo | 78.6% | 83.7% | 89.2% | 84.0% | 73.7% | 64.5% | 3.1% | 5.7 hours |
| Nagoya | 80.5% | 80.0% | 81.2% | 80.6% | 68.0% | 57.9% | 5.0% | 5.5 hours |
| Osaka | 80.0% | 80.4% | 84.7% | 81.8% | 69.2% | 59.1% | 4.6% | 5.2 hours |
| Hiroshima | 80.6% | 81.3% | 84.9% | 82.3% | 70.4% | 60.3% | 5.4% | 4.6 hours |
| Takamatsu | 79.2% | 80.5% | 83.2% | 81.1% | 67.5% | 56.8% | 7.8% | 4.7 hours |
| Fukuoka | 68.7% | 71.6% | 74.0% | 71.5% | 53.4% | 40.0% | 8.0% | 3.6 hours |
| Kagoshima | 74.3% | 73.3% | 77.2% | 75.0% | 58.6% | 45.9% | 5.6% | 4.8 hours |
| Naha | 68.7% | 69.9% | 69.4% | 69.3% | 52.3% | 38.5% | 52.8% | 3.4 hours |
"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 / 3 days starting that day (counted from the actual consecutive records, not by multiplying each day's share). They are a guide for multi-night trips and outdoor plans. "Windy days" is the share of days with a daily mean wind speed of 5 m/s or more. The sunshine averages include estimates from March 2021 onward at some stations.
Stations with the highest and lowest dry-day rates (December average)
Highest
Maebashi / Yorii / Chichibu / Kanna / Isesaki / Kumagaya / Kami-Satomi / Kiryu / Tatebayashi / Utsunomiya
Comfort in December (5 levels)
Based on observations of dry-day rate, sunshine, wind, and temperature for 1996–2025 (30 years), each station is rated on 5 levels of comfort for December. The tables also show the values behind each rating and the factor that lowered it most (the main factor). Some stations with short sunshine records are not rated.
Each dot is 1 station. The colors match the levels in the legend. The top and bottom lists are below.
Most comfortable stations (top)
| Station | Level | Main factor | Dry-day rate | Sunshine (avg.) | Windy days | High (avg.) | Low (avg.) |
|---|---|---|---|---|---|---|---|
| Saito | Comfortable | None | 83.6% | 6.0 hours | 1.5% | 15.0°C | 2.9°C |
| Takanabe | Comfortable | None | 83.6% | 6.2 hours | 0.3% | 14.8°C | 4.0°C |
| Hyuga | Comfortable | None | 84.6% | 5.9 hours | 0.0% | 14.7°C | 3.7°C |
| Miyazaki | Comfortable | None | 84.7% | 6.1 hours | 11.6% | 15.0°C | 4.8°C |
| Kushima | Comfortable | None | 80.6% | 5.7 hours | 0.6% | 15.3°C | 4.3°C |
| Kochi | Comfortable | None | 83.2% | 6.2 hours | 0.1% | 14.4°C | 4.2°C |
| Hiwasa | Comfortable | None | 83.2% | 6.0 hours | 0.7% | 14.3°C | 5.2°C |
| Aki | Comfortable | None | 82.3% | 6.2 hours | 0.0% | 14.3°C | 5.6°C |
| Shizuoka | Comfortable | None | 83.5% | 6.6 hours | 1.0% | 14.2°C | 4.7°C |
| Shibushi | Comfortable | None | 80.3% | 5.6 hours | 0.1% | 15.2°C | 4.1°C |
Harshest stations (bottom)
| Station | Level | Main factor | Dry-day rate | Sunshine (avg.) | Windy days | High (avg.) | Low (avg.) |
|---|---|---|---|---|---|---|---|
| Haboro | Harsh | Cold | 25.6% | 1.0 hours | 58.0% | 1.0°C | -4.8°C |
| Rumoi | Harsh | Cold | 28.6% | 1.0 hours | 78.5% | 1.3°C | -4.4°C |
| Wakkanai | Harsh | Cold | 32.0% | 0.9 hours | 43.0% | 0.0°C | -4.3°C |
| Esashi | Harsh | Cold | 35.5% | 1.0 hours | 72.8% | 4.3°C | -1.2°C |
| Suttsu | Harsh | Cold | 26.4% | 0.8 hours | 27.7% | 1.9°C | -2.9°C |
| Kutchan | Harsh | Cold | 18.8% | 1.2 hours | 10.0% | -0.1°C | -6.8°C |
| Hamaoni-Shibetsu | Harsh | Cold | 39.5% | 1.9 hours | 39.3% | -1.1°C | -7.0°C |
| Cape Soya | Harsh | Cold | 56.2% | 0.9 hours | 92.7% | -0.2°C | -4.4°C |
| Hijiori | Harsh | Cold | 16.5% | 1.2 hours | 0.0% | 3.6°C | -2.2°C |
| Nakagawa | Harsh | Cold | 22.5% | 1.0 hours | 7.2% | -0.9°C | -8.4°C |
Stations are ordered by their rating from the observations. "Windy days" is the share of days with a daily mean wind speed of 5 m/s or more, and "Sunshine (avg.)" is the monthly average of daily sunshine hours (including estimates from March 2021 onward at some stations).
Typhoon approaches in December (5 broad areas)
| Area | Total approach days (1951–2025) |
|---|---|
| Hokkaido | 0 days |
| Honshu | 0 days |
| Shikoku | 0 days |
| Kyushu | 0 days |
| Okinawa and Amami | 2 days |
The total number of days in December on which the center of a typhoon came within 300 km of a staffed weather station in each area, from 75 years of confirmed records. The bars compare the areas within this table, with the busiest area drawn longest. The Izu and Ogasawara Islands are not included in Honshu (listed separately).
Typhoon approach calendar / Look up past typhoons by date range
What makes December distinctive
The December numbers have a feature unlike other months. In measurements over the 30 years 1996–2025, the nationwide average dry-day rate fell below November to 65.9%, yet the share of 3 straight days without precipitation rose to 40.6%. This is because places with and without precipitation become fixed; the top gathered in northern Kanto and Saitama, at Maebashi (89.4%) / Chichibu (88.8%) / Isesaki (88.6%), and the bottom was Hokkaido's Kutchan (18.8%) / Etanbetsu (22%) and the Sea of Japan side's Sakata (22.5%) / Shinjo (22.6%).
This contrast also shows at major stations. Tokyo had a dry-day rate of 84% / a 3-day figure of 64.5%, Hiroshima 82.3% and 60.3%, and Sendai 81.9% and 58.9%, records that make scheduling easy, while Niigata was at 29.4% and 3.5% and Kanazawa at 25.5% and 3.9%. The 3-day record opened up this far depending on the place. The temperature range was also wide, with average highs from 23°C at Ishigakijima Island to -1.9°C at Nayoro and average lows reaching -10.7°C at Etanbetsu. Days with a daily mean wind speed of 5 m/s or more were at Yonagunijima Island (83%) / Rumoi (78.5%) / Cape Muroto (74.4%), with both islands and port towns on the Sea of Japan side ranking near the top.
The record values in this commentary are as compiled in September 2026, and the normals are based on 1996–2025 (30 years).
Other months and calendars
November calendar January calendar
When to travel calendar (holidays, long weekends, and comfort levels for 12 months at once)
Each station's page also has a 12-month calendar for that station.