Dry-day rate calendar for September
Period: observations for 1996–2025 (30 years)
This is the month when the autumn rain front and typhoons overlap. In the 1996–2025 records, many stations see dry-day rates one step lower than in summer, and the colors also change between the first and second halves of the month.
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.
September 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: Oma / Abashiri / Rebun (details in the comfort section below).
Dry-day rates across Japan (September 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 | 70.4% | 65.5% | 65.7% | 67.2% | 49.2% | 35.4% | 8.4% | 5.5 hours |
| Sendai | 55.1% | 65.1% | 67.0% | 62.4% | 45.0% | 33.3% | 4.6% | 4.3 hours |
| Niigata | 59.4% | 62.7% | 58.0% | 60.0% | 39.5% | 26.5% | 7.2% | 5.4 hours |
| Kanazawa | 57.1% | 59.3% | 60.6% | 59.0% | 40.9% | 28.4% | 11.9% | 5.3 hours |
| Tokyo | 61.7% | 64.5% | 62.7% | 63.0% | 46.8% | 34.5% | 5.4% | 4.3 hours |
| Nagoya | 62.5% | 65.0% | 66.7% | 64.7% | 47.8% | 36.0% | 4.6% | 5.4 hours |
| Osaka | 62.9% | 69.8% | 69.8% | 67.5% | 50.7% | 38.5% | 2.0% | 5.5 hours |
| Hiroshima | 71.5% | 70.1% | 75.2% | 72.2% | 56.8% | 44.5% | 11.7% | 5.6 hours |
| Takamatsu | 69.8% | 67.7% | 70.6% | 69.4% | 53.2% | 40.6% | 1.8% | 5.4 hours |
| Fukuoka | 61.5% | 68.0% | 72.1% | 67.2% | 50.9% | 39.4% | 6.7% | 5.5 hours |
| Kagoshima | 63.6% | 61.5% | 70.1% | 65.1% | 49.2% | 37.6% | 8.0% | 6.0 hours |
| Naha | 55.4% | 56.9% | 62.2% | 58.2% | 41.2% | 30.2% | 40.6% | 6.1 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 (September average)
Highest
Kukokitamachi / Fukuyama / Kasaoka / Kure / Okayama / Takehara / Matsuyama-Minamiyoshida / Ube / Tamano / Ikuchijima Island
Lowest
Washikura / Naze / Komanoyu / Hachijojima Island / Nasu Highlands / Kusatsu / Yaemigahara / Oku-Nikko / Owase / Yakushima Island
Comfort in September (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 September. 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.) |
|---|---|---|---|---|---|---|---|
| Oma | Comfortable | None | 66.1% | 5.8 hours | 6.0% | 22.9°C | 16.3°C |
| Abashiri | Comfortable | None | 67.2% | 5.7 hours | 6.0% | 21.2°C | 13.7°C |
| Rebun | Comfortable | None | 66.1% | 6.0 hours | 15.8% | 20.9°C | 14.8°C |
| Shiura | Comfortable | None | 64.1% | 5.7 hours | 1.5% | 23.7°C | 15.4°C |
| Goshogawara | Comfortable | None | 63.8% | 5.6 hours | 0.5% | 24.8°C | 15.4°C |
| Kutsugata | Comfortable | None | 65.3% | 5.9 hours | 14.6% | 20.8°C | 13.9°C |
| Ajigasawa | Comfortable | None | 63.0% | 5.6 hours | 0.4% | 23.9°C | 15.7°C |
| Kuroishi | Comfortable | None | 66.0% | 5.5 hours | 1.4% | 24.3°C | 14.7°C |
| Toyotomi | Comfortable | None | 63.1% | 5.7 hours | 4.5% | 20.9°C | 11.4°C |
| Mombetsu | Comfortable | None | 66.9% | 5.5 hours | 3.7% | 21.2°C | 13.0°C |
Harshest stations (bottom)
| Station | Level | Main factor | Dry-day rate | Sunshine (avg.) | Windy days | High (avg.) | Low (avg.) |
|---|---|---|---|---|---|---|---|
| Ishigakijima Island | Harsh | Heat | 60.4% | 6.4 hours | 34.5% | 31.2°C | 26.2°C |
| Naha | Harsh | Heat | 58.2% | 6.1 hours | 40.6% | 30.9°C | 26.0°C |
| Naze | Harsh | Heat | 48.5% | 4.5 hours | 3.8% | 30.7°C | 24.6°C |
| Yonagunijima Island | Harsh | Heat | 59.6% | 6.2 hours | 54.6% | 30.4°C | 25.5°C |
| Minami-Daito | Harsh | Heat | 62.2% | 7.5 hours | 31.8% | 31.2°C | 25.2°C |
| Okinoerabu | Tough | Heat | 65.1% | 7.1 hours | 44.1% | 30.4°C | 25.7°C |
| Hateruma | Tough | Heat | 63.4% | 6.7 hours | 30.9% | 30.7°C | 25.7°C |
| Nago | Tough | Heat | 56.8% | 6.2 hours | 18.3% | 31.0°C | 25.4°C |
| Miyakojima Island | Tough | Heat | 60.2% | 6.0 hours | 31.0% | 30.3°C | 25.8°C |
| Ibaruma | Tough | Heat | 59.2% | 6.2 hours | 25.3% | 30.5°C | 25.7°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 September (5 broad areas)
| Area | Total approach days (1951–2025) |
|---|---|
| Hokkaido | 57 days |
| Honshu | 183 days |
| Shikoku | 114 days |
| Kyushu | 165 days |
| Okinawa and Amami | 365 days |
The total number of days in September 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 September distinctive
In September, the places least prone to rain gather on the Seto Inland Sea. In measurements over the 30 years 1996–2025, the top was lined with Fukuyama (73.8%) / Kure (73.5%) / Okayama (73.1%) / Uchinomi (72.6%) / Hiroshima (72.2%), all on the Seto Inland Sea coast. The low side was Naze (48.5%) / Hachijojima Island (49.3%) on the islands and Nasu Highlands (49.4%) in the mountains. This is when typhoons and autumn rain overlap; the nationwide average was 62.6%, and the share of 3 straight days without precipitation fell to 33.3%. For a multi-night plan, Hiroshima's 3-day figure of 44.5% and Takamatsu's 40.6% make a good base.
An unusual face appeared in the temperature lineup. The bottom of the average highs was Oku-Nikko at 19.4°C, lower than Nemuro at 19.9°C or Kushiro at 20.4°C. At the top, the Okinawa group held in the 31°C range, with Kita-Daito at 31.3°C / Ishigakijima Island at 31.2°C, and Naha, with an average low of 26°C, was still an extension of summer. In inland Hokkaido, average lows dropped to Etanbetsu 10°C / Nayoro 10.1°C, so autumn and summer share the same month. Days with a daily mean wind speed of 5 m/s or more were at Cape Muroto (69.8%) / Choshi (55.6%), and capes and islands lie on the path of typhoons.
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
August calendar October calendar
Typhoon approach calendar (September 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.