Koesan in Fall
In fall (September, October and November), Koesan sees average daytime highs around 19°C and overnight lows near 9°C, with 242 mm of precipitation over about 21 wet days across the season. It is the 2nd-warmest season and the 2nd-wettest season.
Over the season highs ease from about 27°C in early September to 8°C by late November. The sky is clear or mostly clear about 41% of the time across fall, and the air most often feels dry.
Fall is Koesan's best season of the year to visit on our travel score. For the whole year in context, see Koesan's year-round climate.
- Avg daytime high
- 19°C
- 2nd-warmest season
- Avg overnight low
- 9°C
- Precipitation
- 242 mm
- 21 wet days
- Avg wind
- 8 km/h
- Travel score
- 5.8
- best season of the year
- Months
- Sep · Oct · Nov
Temperature in Koesan in Fall
Over the season highs ease from about 27°C in early September to 8°C by late November.
A typical fall day in Koesan reaches about 19°C and drops to 9°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Koesan
Once humidity and wind are folded in, fall brings about 0 days that feel above 32°C and 16 that feel at or below 0°C.
The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.
Koesan 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° / -6° | 23 | 4.7 | 3.3 | 9.8 | 0.0 |
| Feb | 5° / -4° | 33 | 4.6 | 2.1 | 10.6 | 0.4 |
| Mar | 11° / 0° | 54 | 7.1 | 2.1 | 11.7 | 3.0 |
| Apr | 18° / 6° | 83 | 7.7 | 0.2 | 12.9 | 6.1 |
| May | 23° / 12° | 94 | 8 | 0 | 13.9 | 7.1 |
| Jun | 27° / 17° | 125 | 8.8 | 0 | 14.5 | 6.5 |
| Jul | 28° / 21° | 258 | 16.7 | 0 | 14.3 | 4.8 |
| Aug | 29° / 22° | 219 | 15.5 | 0 | 13.4 | 4.8 |
| Sep | 25° / 16° | 139 | 8.9 | 0 | 12.2 | 6.9 |
| Oct | 19° / 9° | 58 | 5.2 | 0 | 11 | 7.0 |
| Nov | 12° / 2° | 44 | 6.6 | 0.4 | 10 | 3.4 |
| Dec | 5° / -4° | 26 | 4.6 | 2.1 | 9.5 | 0.2 |
Cloud cover in Fall
The sky is clear or mostly clear about 41% of the time across fall.
Chance of precipitation in Fall
Koesan gets around 242 mm of rain and snow over 21 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 8 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 48 min in early September to 9 h 42 min 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 3.5 kWh/m².
Hazard calendar for Koesan
In fall, Koesan overlaps its rainy season season. The full year is below, with each hazard's peak months called out.
Koesan's rainy season runs June–September, when most of the year's rain falls.
Is fall a good time to visit Koesan?
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 reasonable time to visit Koesan for sightseeing.
What to pack for Koesan in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Koesan sees daytime highs around 19°C and nights near 9°C. Pack a warm layer. Worth having: light clothes and rain gear. About 21 days see rain.
UV index in Koesan in Fall
Clear-sky midday UV across fall averages around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Koesan peaks around August 14 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 5 | 6 | 7 | 7 | 8 | 9 | 8 | 5 | 3 | 2 |
| Level | Low | Moderate | Moderate | High | High | Very high | Very high | Very high | Very high | High | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 5 | Moderate |
| Apr | 6 | High |
| May | 7 | High |
| Jun | 7 | Very high |
| Jul | 8 | Very high |
| Aug | 9 | Very high |
| Sep | 8 | Very high |
| Oct | 5 | High |
| Nov | 3 | Moderate |
| Dec | 2 | Low |
Air quality in Koesan 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 Koesan is worst in March — around 80 µg/m³ PM2.5 (unhealthy), about 1.8× the cleanest month (July, 45 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) | 69 | 72 | 80 | 65 | 58 | 54 | 45 | 45 | 56 | 67 | 72 | 65 |
| Level | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Poor | Poor | Poor | Unhealthy | Unhealthy | Unhealthy | Unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 69 | Unhealthy |
| Feb | 72 | Unhealthy |
| Mar | 80 | Unhealthy |
| Apr | 65 | Unhealthy |
| May | 58 | Unhealthy |
| Jun | 54 | Poor |
| Jul | 45 | Poor |
| Aug | 45 | Poor |
| Sep | 56 | Unhealthy |
| Oct | 67 | Unhealthy |
| Nov | 72 | Unhealthy |
| Dec | 65 | Unhealthy |
Where is Koesan?
Koesan sits at 36.8°N, 127.8°E, 116 m above sea level, in South Korea. The nearest listed city is Jungpyong, 19 km away.
Topography around Koesan
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Koesan.
Within 3 km, the terrain around Koesan has significant variations in elevation — a maximum elevation change of 298 m around an average of 173 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 866 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,408 m.
The land around Koesan is covered by trees (58%) within 3 km, trees (74%) within 16 km, and trees (72%) within 80 km.
South Korea travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type C / F
- 220 V · 60 Hz
- Prices
- ≈ 57% of US
- price level, 2025
- GDP per capita
- $36,227
- 2025
- Happiness
- 6.0 / 10
- World Happiness, 2025
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 0.5
- per 100k, 2023
- Road deaths
- 8.6
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Moderate
- EF EPI 522
- 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 Koesan (36.8108°, 127.7947°, elevation 116 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.