Rumoi in Fall
In fall (September, October and November), Rumoi sees average daytime highs around 14°C and overnight lows near 8°C, with 375 mm of precipitation over about 49 wet days across the season. It is the 2nd-warmest season and the wettest season of the year.
Over the season highs ease from about 22°C in early September to 3°C by late November. The sky is clear or mostly clear about 20% of the time across fall, and the air most often feels dry.
Fall is Rumoi's 2nd-best season to visit on our travel score. For the whole year in context, see Rumoi's year-round climate.
- Avg daytime high
- 14°C
- 2nd-warmest season
- Avg overnight low
- 8°C
- Precipitation
- 375 mm
- 49 wet days
- Avg wind
- 13 km/h
- Travel score
- 3.3
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Rumoi in Fall
Over the season highs ease from about 22°C in early September to 3°C by late November.
A typical fall day in Rumoi reaches about 14°C and drops to 8°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Rumoi
Once humidity and wind are folded in, fall brings about 0 days that feel above 32°C and 24 that feel at or below 0°C.
The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.
Rumoi weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | -3° / -9° | 67 | 17.3 | 21 | 9.1 | 0.0 |
| Feb | -2° / -8° | 55 | 14.2 | 17.1 | 10.2 | 0.0 |
| Mar | 2° / -5° | 66 | 13.6 | 14.1 | 11.6 | 0.0 |
| Apr | 8° / 1° | 66 | 11.9 | 4.6 | 13.2 | 1.5 |
| May | 14° / 7° | 78 | 11.7 | 0.3 | 14.5 | 3.8 |
| Jun | 18° / 12° | 70 | 10.4 | 0 | 15.2 | 5.6 |
| Jul | 22° / 17° | 121 | 12.4 | 0 | 14.9 | 6.2 |
| Aug | 24° / 18° | 143 | 13.7 | 0 | 13.8 | 6.2 |
| Sep | 20° / 14° | 137 | 13.9 | 0 | 12.3 | 5.7 |
| Oct | 14° / 8° | 115 | 15.9 | 0.3 | 10.8 | 3.6 |
| Nov | 6° / 1° | 124 | 19.4 | 11.4 | 9.4 | 0.7 |
| Dec | -0° / -5° | 102 | 21.6 | 22.6 | 8.8 | 0.0 |
Cloud cover in Fall
The sky is clear or mostly clear about 20% of the time across fall.
Chance of precipitation in Fall
Rumoi gets around 375 mm of rain and snow over 49 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 13 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 13 h 06 min in early September to 9 hours by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 2.7 kWh/m².
Hazard calendar for Rumoi
In fall, Rumoi overlaps its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Rumoi sits in the Pacific typhoon belt; the season peaks July–October.
Is fall a good time to visit Rumoi?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a weaker month for outdoor sightseeing in Rumoi.
What to pack for Rumoi in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Rumoi sees daytime highs around 14°C and nights near 8°C. Pack a warm layer and rain gear. Worth having: a heavy coat. About 49 days see rain.
Sea temperature near Rumoi in Fall
The nearest coast averages about 17°C across fall — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea offshore is warmest in August at about 21°C and coldest in February near 5°C.
It's comfortable for a long swim from Aug 3 to Sep 20 — about 1.6 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 6 | 5 | 5 | 7 | 10 | 14 | 18 | 21 | 21 | 17 | 13 | 9 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Refreshing | Cool | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 6 | Bracing |
| Feb | 5 | Bracing |
| Mar | 5 | Bracing |
| Apr | 7 | Bracing |
| May | 10 | Bracing |
| Jun | 14 | Bracing |
| Jul | 18 | Cool |
| Aug | 21 | Refreshing |
| Sep | 21 | Refreshing |
| Oct | 17 | Cool |
| Nov | 13 | Bracing |
| Dec | 9 | Bracing |
UV index in Rumoi in Fall
Clear-sky midday UV across fall averages around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Rumoi peaks around August 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 2 | 3 | 5 | 7 | 7 | 7 | 8 | 6 | 4 | 2 | 1 |
| Level | Low | Low | Moderate | High | Very high | High | High | Very high | High | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Low |
| Mar | 3 | Moderate |
| Apr | 5 | High |
| May | 7 | Very high |
| Jun | 7 | High |
| Jul | 7 | High |
| Aug | 8 | Very high |
| Sep | 6 | High |
| Oct | 4 | Moderate |
| Nov | 2 | Low |
| Dec | 1 | Low |
Air quality in Rumoi in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in Rumoi is worst in April — around 17 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (December, 7 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 7 | 10 | 16 | 17 | 15 | 10 | 10 | 8 | 7 | 9 | 9 | 7 |
| Level | Good | Good | Moderate | Moderate | Moderate | Good | Good | Good | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 7 | Good |
| Feb | 10 | Good |
| Mar | 16 | Moderate |
| Apr | 17 | Moderate |
| May | 15 | Moderate |
| Jun | 10 | Good |
| Jul | 10 | Good |
| Aug | 8 | Good |
| Sep | 7 | Good |
| Oct | 9 | Good |
| Nov | 9 | Good |
| Dec | 7 | Good |
Where is Rumoi?
Rumoi sits at 43.9°N, 141.6°E, 35 m above sea level, in Japan. The nearest listed city is Fukagawa, 41 km away.
Topography around Rumoi
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Rumoi.
Within 3 km, the terrain around Rumoi has only modest variations in elevation — a maximum elevation change of 248 m around an average of 40 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 731 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,471 m.
The land around Rumoi is covered by trees (41%) and water (34%) within 3 km, trees (53%) and water (40%) within 16 km, and trees (51%) and water (35%) within 80 km.
Japan travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 100 V · 50 / 60 Hz
- Prices
- ≈ 65% of US
- price level, 2025
- GDP per capita
- $35,951
- 2025
- Happiness
- 6.1 / 10
- World Happiness, 2025
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 0.2
- per 100k, 2023
- Road deaths
- 3.6
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very low
- EF EPI 446
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Rumoi (43.9344°, 141.6428°, elevation 35 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.