Isa in Winter
In winter (December, January and February), Isa sees average daytime highs around 12°C and overnight lows near 4°C, with 278 mm of precipitation over about 28 wet days across the season. It is the coldest season of the year and the driest season of the year.
Across winter, daytime highs hold fairly steady around 12°C. The sky is clear or mostly clear about 28% of the time across winter, and the air most often feels dry.
Winter is Isa's weakest season of the year to visit on our travel score. For the whole year in context, see Isa's year-round climate.
- Avg daytime high
- 12°C
- coldest season of the year
- Avg overnight low
- 4°C
- Precipitation
- 278 mm
- 28 wet days
- Avg wind
- 10 km/h
- Travel score
- 3.1
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Isa in Winter
Across winter, daytime highs hold fairly steady around 12°C.
A typical winter day in Isa reaches about 12°C and drops to 4°C overnight. The warmest of the three months is December, the coolest January.
How winter really feels in Isa
Once humidity and wind are folded in, winter brings about 0 days that feel above 32°C and 0 that feel at or below 0°C.
winter sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Isa weather by month
How the three winter months (December, January and February) 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 | 11° / 4° | 82 | 9.8 | 0.8 | 10.1 | 2.6 |
| Feb | 12° / 4° | 106 | 9.6 | 0.4 | 10.8 | 3.1 |
| Mar | 15° / 7° | 151 | 13.2 | 0.1 | 11.8 | 4.3 |
| Apr | 20° / 11° | 184 | 12.1 | 0 | 12.8 | 5.8 |
| May | 23° / 16° | 209 | 12.3 | 0 | 13.6 | 6.3 |
| Jun | 26° / 20° | 528 | 19.6 | 0 | 14.1 | 4.9 |
| Jul | 30° / 24° | 373 | 20.1 | 0 | 13.9 | 3.9 |
| Aug | 31° / 24° | 184 | 17.2 | 0 | 13.2 | 3.8 |
| Sep | 28° / 21° | 194 | 14.3 | 0 | 12.2 | 5.3 |
| Oct | 24° / 16° | 110 | 8.7 | 0 | 11.2 | 7.2 |
| Nov | 18° / 10° | 111 | 8.8 | 0 | 10.4 | 6.1 |
| Dec | 13° / 5° | 90 | 8.7 | 0.2 | 9.9 | 3.7 |
Cloud cover in Winter
The sky is clear or mostly clear about 28% of the time across winter.
Chance of precipitation in Winter
Isa gets around 278 mm of rain and snow over 28 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 10 km/h across winter.
Sunrise & sunset in Winter
Daylight runs from about 10 h 06 min in early December to 11 h 12 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 2.8 kWh/m².
Hazard calendar for Isa
In winter, Isa overlaps its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Isa sits in the Pacific typhoon belt; the season peaks July–October.
Isa's rainy season runs June–July, when most of the year's rain falls.
Is winter a good time to visit Isa?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a weaker month for outdoor sightseeing in Isa.
What to pack for Isa in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Isa sees daytime highs around 12°C and nights near 4°C. Pack a warm layer. Worth having: rain gear. About 28 days see rain.
Sea temperature near Isa in Winter
The nearest coast averages about 18°C across winter — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 23 km away) is warmest in August at about 28°C and coldest in February near 16°C.
It's comfortable for a long swim from May 16 to Dec 4 — about 6.7 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 17 | 16 | 17 | 18 | 20 | 23 | 26 | 28 | 27 | 24 | 22 | 19 |
| Comfort | Cool | Cool | Cool | Cool | Refreshing | Refreshing | Warm | Warm | Warm | Warm | Refreshing | Cool |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 17 | Cool |
| Feb | 16 | Cool |
| Mar | 17 | Cool |
| Apr | 18 | Cool |
| May | 20 | Refreshing |
| Jun | 23 | Refreshing |
| Jul | 26 | Warm |
| Aug | 28 | Warm |
| Sep | 27 | Warm |
| Oct | 24 | Warm |
| Nov | 22 | Refreshing |
| Dec | 19 | Cool |
UV index in Isa in Winter
Clear-sky midday UV across winter 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 Isa peaks around June 22 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 5 | 7 | 8 | 8 | 11 | 11 | 9 | 10 | 6 | 5 | 3 |
| Level | Moderate | Moderate | High | Very high | Very high | Extreme | Extreme | Very high | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 5 | Moderate |
| Mar | 7 | High |
| Apr | 8 | Very high |
| May | 8 | Very high |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 9 | Very high |
| Sep | 10 | Very high |
| Oct | 6 | High |
| Nov | 5 | Moderate |
| Dec | 3 | Moderate |
Air quality in Isa in Winter
Average fine-particle pollution (PM2.5) through the year — so you can see where winter falls, not just the annual average.
Air quality in Isa is worst in March — around 24 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (July, 13 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) | 17 | 20 | 24 | 24 | 22 | 18 | 13 | 14 | 14 | 14 | 16 | 15 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 17 | Moderate |
| Feb | 20 | Moderate |
| Mar | 24 | Moderate |
| Apr | 24 | Moderate |
| May | 22 | Moderate |
| Jun | 18 | Moderate |
| Jul | 13 | Moderate |
| Aug | 14 | Moderate |
| Sep | 14 | Moderate |
| Oct | 14 | Moderate |
| Nov | 16 | Moderate |
| Dec | 15 | Moderate |
Where is Isa?
Isa sits at 32.1°N, 130.6°E, 183 m above sea level, in Japan. The nearest listed city is Ōkuchi-shinohara, 1.0 km away.
Topography around Isa
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Isa.
Within 3 km, the terrain around Isa has significant variations in elevation — a maximum elevation change of 275 m around an average of 207 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 962 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,715 m.
The land around Isa is covered by trees (44%) and cropland (38%) within 3 km, trees (87%) within 16 km, and trees (60%) and water (30%) 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 Isa (32.0672°, 130.6118°, elevation 183 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.