Dry-day rate calendar for August
Period: observations for 1996–2025 (30 years)
This is a month with many days under the summer high, mixed with rain from evening showers and typhoons. In the 1996–2025 records, even stations with fairly high dry-day rates sometimes see little growth in the 3-day share, so the consecutive-day columns are a useful reference for multi-night plans.
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.
August 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: Sugadaira / Haboro / Otaru (details in the comfort section below).
Dry-day rates across Japan (August 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 | 71.3% | 69.1% | 68.1% | 69.5% | 53.2% | 40.8% | 11.5% | 5.4 hours |
| Sendai | 72.7% | 62.4% | 60.9% | 65.2% | 48.4% | 36.7% | 2.7% | 4.7 hours |
| Niigata | 79.9% | 66.5% | 58.7% | 68.1% | 52.4% | 41.5% | 4.9% | 6.8 hours |
| Kanazawa | 79.9% | 65.8% | 64.7% | 70.0% | 55.5% | 45.1% | 8.9% | 7.1 hours |
| Tokyo | 78.7% | 71.4% | 68.1% | 72.6% | 56.9% | 45.4% | 5.8% | 5.7 hours |
| Nagoya | 78.1% | 68.3% | 65.4% | 70.4% | 55.9% | 45.0% | 3.6% | 6.5 hours |
| Osaka | 81.6% | 75.8% | 69.0% | 75.3% | 61.1% | 50.1% | 3.4% | 7.2 hours |
| Hiroshima | 79.6% | 70.9% | 74.0% | 74.8% | 60.4% | 49.9% | 6.3% | 6.8 hours |
| Takamatsu | 82.2% | 75.1% | 75.5% | 77.5% | 64.3% | 54.2% | 3.7% | 7.2 hours |
| Fukuoka | 75.3% | 67.6% | 64.0% | 68.8% | 52.5% | 41.5% | 3.2% | 6.6 hours |
| Kagoshima | 70.9% | 61.5% | 60.8% | 64.3% | 47.6% | 35.3% | 9.8% | 6.7 hours |
| Naha | 56.0% | 59.2% | 59.2% | 58.2% | 40.6% | 29.6% | 39.9% | 6.6 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 (August average)
Highest
Tamano / Akashi / Ieshima / Tadotsu / Gunge / Kanku Island / Uchinomi / Ikuchijima Island / Kobe Airport / Katsuura
Comfort in August (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 August. 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.) |
|---|---|---|---|---|---|---|---|
| Sugadaira | Comfortable | None | 64.4% | 5.8 hours | 0.0% | 24.7°C | 15.7°C |
| Haboro | Comfortable | None | 66.3% | 5.7 hours | 7.2% | 25.1°C | 17.7°C |
| Otaru | Comfortable | None | 68.8% | 5.4 hours | 0.3% | 26.1°C | 18.7°C |
| Abashiri | Comfortable | None | 66.4% | 5.3 hours | 2.9% | 23.8°C | 17.0°C |
| Rumoi | Comfortable | None | 67.4% | 5.7 hours | 21.5% | 25.0°C | 18.1°C |
| Oma | Comfortable | None | 68.5% | 5.2 hours | 4.9% | 25.0°C | 19.6°C |
| Ajigasawa | Comfortable | None | 67.1% | 6.1 hours | 0.1% | 27.2°C | 19.8°C |
| Kutsugata | Comfortable | None | 69.9% | 5.1 hours | 5.8% | 23.3°C | 17.1°C |
| Esashi | Comfortable | None | 69.1% | 5.5 hours | 9.5% | 26.3°C | 20.1°C |
| Shiura | Comfortable | None | 68.0% | 5.7 hours | 3.9% | 26.8°C | 19.9°C |
Harshest stations (bottom)
| Station | Level | Main factor | Dry-day rate | Sunshine (avg.) | Windy days | High (avg.) | Low (avg.) |
|---|---|---|---|---|---|---|---|
| Naha | Harsh | Heat | 58.2% | 6.6 hours | 39.9% | 31.9°C | 26.9°C |
| Ishigakijima Island | Harsh | Heat | 63.2% | 7.5 hours | 36.4% | 32.1°C | 27.4°C |
| Nago | Harsh | Heat | 56.8% | 6.8 hours | 17.8% | 32.0°C | 26.6°C |
| Naze | Harsh | Heat | 53.9% | 5.7 hours | 4.7% | 32.2°C | 26.1°C |
| Hateruma | Harsh | Heat | 64.2% | 7.4 hours | 23.7% | 31.9°C | 26.6°C |
| Yonagunijima Island | Harsh | Heat | 67.3% | 7.4 hours | 38.3% | 31.6°C | 26.5°C |
| Miyakojima Island | Harsh | Heat | 60.1% | 6.8 hours | 24.3% | 31.4°C | 26.7°C |
| Okinoerabu | Harsh | Heat | 68.5% | 8.1 hours | 38.3% | 31.4°C | 26.6°C |
| Kumejima Island | Harsh | Heat | 66.9% | 7.5 hours | 20.7% | 32.0°C | 26.5°C |
| Ohara | Harsh | Heat | 62.0% | 7.1 hours | 19.6% | 31.9°C | 26.3°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 August (5 broad areas)
| Area | Total approach days (1951–2025) |
|---|---|
| Hokkaido | 71 days |
| Honshu | 237 days |
| Shikoku | 147 days |
| Kyushu | 220 days |
| Okinawa and Amami | 448 days |
The total number of days in August 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 August distinctive
The August records line up places with little rain along the coast. In measurements over the 30 years 1996–2025, the top was taken by Kagawa's Tadotsu (80.2%) / Uchinomi (79.8%), the Boso Peninsula's Katsuura (79.2%) / Tateyama (79.1%), and Kure (79%). Among major stations, Takamatsu was also solid, with a dry-day rate of 77.5% / a share of 3 straight days without precipitation of 54.2%, followed by Osaka at 75.3% and 50.1% and Hiroshima at 74.8% and 49.9%. For packing plans into a multi-night stay, the Seto Inland Sea side made scheduling easy.
The Nansei Islands, on the other hand, saw their numbers drop. Naha fell from 66.7% in July to 58.2%, and its 3-day figure from 40.6% to 29.6%, while Naze (53.9%) also landed on the low side. Because this is the season when typhoons pass, the idea that the farther south you go the less rain you get does not hold in August. On the heat side, average highs were high inland and in cities, at Tajimi 34.2°C / Kyoto 34°C / Osaka 33.9°C, with Nemuro 21.3°C / Kushiro 22.1°C at the bottom. For cool nights, Oku-Nikko (15.9°C) lined up with Nemuro (15.2°C) / Nayoro (15.6°C); in exchange for more frequent rain, cool mornings remained in the Honshu highlands too.
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
July calendar September calendar
Typhoon approach calendar (August is a month with a record of typhoon approaches)
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.