Seosan weather in September
In September, Seosan sees average daytime highs of 25°C and overnight lows near 18°C, with 133 mm of rain across 7.5 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 3rd-wettest month of the year here.
Highs ease over the month, from about 27°C in the first days to 23°C by the end. The sky is clear or mostly clear about 41% of the time in September, and the air most often feels humid.
Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Seosan's 6th-clearest and 11th-windiest month. For the whole year in context, see Seosan's year-round climate.
- Daytime high
- 25°
- 3rd warmest
- Overnight low
- 18°
- 10th coldest
- Rainfall
- 133 mm
- 7.5 wet days
- Daylight
- 12 h 12 min
- 6:22 AM – 6:35 PM
- Cloud cover
- 53%
- 6th clearest
- Wind
- 10 km/h
- 11th windiest
- Solar energy
- 4.38 kWh/m²
- Travel score
- 7.2
- out of 10
Seosan is city in South Korea.
- Density
- 100/km²
- people per km²
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in September
Highs ease over the month, from about 27°C in the first days to 23°C by the end.
A typical September day in Seosan reaches about 25°C in the afternoon and slips back to 18°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 28°C. Set against its neighbours, September runs about 4°C cooler than August and about 6°C warmer than October.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 27 | 27 | 27 | 27 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 24 | 24 | 24 | 24 | 24 | 24 | 23 | 23 | 23 | 23 | 23 |
| Avg low (°C) | 21 | 21 | 21 | 21 | 20 | 20 | 20 | 20 | 20 | 20 | 19 | 19 | 19 | 19 | 19 | 18 | 18 | 18 | 18 | 18 | 17 | 17 | 17 | 17 | 17 | 16 | 16 | 16 | 16 | 16 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| 1 | 27 | 21 |
| 2 | 27 | 21 |
| 3 | 27 | 21 |
| 4 | 27 | 21 |
| 5 | 26 | 20 |
| 6 | 26 | 20 |
| 7 | 26 | 20 |
| 8 | 26 | 20 |
| 9 | 26 | 20 |
| 10 | 26 | 20 |
| 11 | 26 | 19 |
| 12 | 26 | 19 |
| 13 | 25 | 19 |
| 14 | 25 | 19 |
| 15 | 25 | 19 |
| 16 | 25 | 18 |
| 17 | 25 | 18 |
| 18 | 25 | 18 |
| 19 | 25 | 18 |
| 20 | 24 | 18 |
| 21 | 24 | 17 |
| 22 | 24 | 17 |
| 23 | 24 | 17 |
| 24 | 24 | 17 |
| 25 | 24 | 17 |
| 26 | 23 | 16 |
| 27 | 23 | 16 |
| 28 | 23 | 16 |
| 29 | 23 | 16 |
| 30 | 23 | 16 |
How September really feels in Seosan
Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.
September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Seosan weather by month
How September compares with the rest of the year at a glance. September is the 3rd-warmest and 3rd-wettest month here — the current month is highlighted below.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 3° / -3° | 22 | 4.9 | 4 | 9.8 | 0.0 |
| Feb | 5° / -2° | 27 | 4.2 | 1.7 | 10.6 | 0.2 |
| Mar | 10° / 2° | 41 | 5.6 | 0.9 | 11.7 | 2.4 |
| Apr | 16° / 7° | 69 | 6.8 | 0 | 12.9 | 5.3 |
| May | 21° / 13° | 79 | 7 | 0 | 13.9 | 7.0 |
| Jun | 25° / 18° | 116 | 7.7 | 0 | 14.5 | 7.1 |
| Jul | 27° / 22° | 245 | 14.8 | 0 | 14.3 | 5.4 |
| Aug | 29° / 23° | 225 | 13.7 | 0 | 13.4 | 5.3 |
| Sep | 25° / 18° | 133 | 7.5 | 0 | 12.2 | 7.2 |
| Oct | 20° / 12° | 55 | 5.3 | 0 | 11 | 7.1 |
| Nov | 12° / 6° | 49 | 7.2 | 0.4 | 10 | 3.6 |
| Dec | 6° / -0° | 26 | 6.1 | 3.4 | 9.5 | 0.4 |
Cloud cover in September
The sky is clear or mostly clear about 41% of the time in September.
Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 47%. Skies tend to open up as the month goes on.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 48 | 48 | 49 | 49 | 50 | 50 | 51 | 51 | 52 | 52 | 52 | 53 | 53 | 53 | 53 | 54 | 54 | 56 | 56 | 56 | 56 | 56 | 57 | 56 | 56 | 56 | 55 | 56 | 56 | 56 |
| Cloudier (%) | 52 | 52 | 51 | 51 | 50 | 50 | 49 | 49 | 48 | 48 | 48 | 47 | 47 | 47 | 47 | 46 | 46 | 44 | 44 | 44 | 44 | 44 | 43 | 44 | 44 | 44 | 45 | 44 | 44 | 44 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 48 | 52 |
| 2 | 48 | 52 |
| 3 | 49 | 51 |
| 4 | 49 | 51 |
| 5 | 50 | 50 |
| 6 | 50 | 50 |
| 7 | 51 | 49 |
| 8 | 51 | 49 |
| 9 | 52 | 48 |
| 10 | 52 | 48 |
| 11 | 52 | 48 |
| 12 | 53 | 47 |
| 13 | 53 | 47 |
| 14 | 53 | 47 |
| 15 | 53 | 47 |
| 16 | 54 | 46 |
| 17 | 54 | 46 |
| 18 | 56 | 44 |
| 19 | 56 | 44 |
| 20 | 56 | 44 |
| 21 | 56 | 44 |
| 22 | 56 | 44 |
| 23 | 57 | 43 |
| 24 | 56 | 44 |
| 25 | 56 | 44 |
| 26 | 56 | 44 |
| 27 | 55 | 45 |
| 28 | 56 | 44 |
| 29 | 56 | 44 |
| 30 | 56 | 44 |
Chance of precipitation in September
Seosan gets around 133 mm of rain over 7.5 wet days in September. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 26% and peaks near 37% on the wettest days. The odds ease toward the end of the month.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 37 | 36 | 35 | 34 | 33 | 32 | 31 | 30 | 29 | 28 | 28 | 27 | 26 | 26 | 25 | 24 | 24 | 23 | 23 | 22 | 22 | 22 | 21 | 21 | 21 | 21 | 21 | 21 | 20 | 20 |
| Rain chance (%) | |
|---|---|
| 1 | 37 |
| 2 | 36 |
| 3 | 35 |
| 4 | 34 |
| 5 | 33 |
| 6 | 32 |
| 7 | 31 |
| 8 | 30 |
| 9 | 29 |
| 10 | 28 |
| 11 | 28 |
| 12 | 27 |
| 13 | 26 |
| 14 | 26 |
| 15 | 25 |
| 16 | 24 |
| 17 | 24 |
| 18 | 23 |
| 19 | 23 |
| 20 | 22 |
| 21 | 22 |
| 22 | 22 |
| 23 | 21 |
| 24 | 21 |
| 25 | 21 |
| 26 | 21 |
| 27 | 21 |
| 28 | 21 |
| 29 | 20 |
| 30 | 20 |
Humidity in September
Most of September feels humid — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, September lands in the humid band about 27% of days. Sticky, muggy-or-worse air turns up on roughly 35% of them.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 1 | 1 | 1 | 1 | 2 | 2 | 3 | 3 | 4 | 5 | 6 | 7 | 8 | 10 | 11 | 13 | 14 | 16 | 18 | 20 | 21 | 23 | 25 | 27 | 29 | 31 | 34 | 36 | 39 | 41 |
| Comfortable (%) | 5 | 6 | 7 | 8 | 9 | 10 | 12 | 13 | 15 | 16 | 18 | 20 | 21 | 23 | 24 | 26 | 27 | 29 | 30 | 31 | 32 | 32 | 33 | 33 | 33 | 33 | 33 | 33 | 33 | 32 |
| Humid (%) | 22 | 24 | 25 | 27 | 28 | 29 | 29 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 29 | 29 | 28 | 28 | 28 | 27 | 27 | 27 | 26 | 25 | 25 | 24 | 23 | 21 | 20 |
| Muggy (%) | 40 | 40 | 39 | 39 | 38 | 38 | 37 | 37 | 36 | 35 | 34 | 32 | 31 | 29 | 28 | 26 | 24 | 22 | 20 | 19 | 17 | 15 | 14 | 12 | 11 | 10 | 9 | 8 | 7 | 6 |
| Oppressive (%) | 29 | 27 | 25 | 23 | 22 | 20 | 18 | 17 | 15 | 13 | 12 | 11 | 10 | 8 | 7 | 7 | 6 | 5 | 4 | 3 | 3 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 0 | 0 |
| Miserable (%) | 3 | 3 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| 1 | 1 | 5 | 22 | 40 | 29 | 3 |
| 2 | 1 | 6 | 24 | 40 | 27 | 3 |
| 3 | 1 | 7 | 25 | 39 | 25 | 2 |
| 4 | 1 | 8 | 27 | 39 | 23 | 2 |
| 5 | 2 | 9 | 28 | 38 | 22 | 2 |
| 6 | 2 | 10 | 29 | 38 | 20 | 1 |
| 7 | 3 | 12 | 29 | 37 | 18 | 1 |
| 8 | 3 | 13 | 30 | 37 | 17 | 1 |
| 9 | 4 | 15 | 30 | 36 | 15 | 1 |
| 10 | 5 | 16 | 30 | 35 | 13 | 0 |
| 11 | 6 | 18 | 30 | 34 | 12 | 0 |
| 12 | 7 | 20 | 30 | 32 | 11 | 0 |
| 13 | 8 | 21 | 30 | 31 | 10 | 0 |
| 14 | 10 | 23 | 30 | 29 | 8 | 0 |
| 15 | 11 | 24 | 30 | 28 | 7 | 0 |
| 16 | 13 | 26 | 29 | 26 | 7 | 0 |
| 17 | 14 | 27 | 29 | 24 | 6 | 0 |
| 18 | 16 | 29 | 28 | 22 | 5 | 0 |
| 19 | 18 | 30 | 28 | 20 | 4 | 0 |
| 20 | 20 | 31 | 28 | 19 | 3 | 0 |
| 21 | 21 | 32 | 27 | 17 | 3 | 0 |
| 22 | 23 | 32 | 27 | 15 | 2 | 0 |
| 23 | 25 | 33 | 27 | 14 | 2 | 0 |
| 24 | 27 | 33 | 26 | 12 | 2 | 0 |
| 25 | 29 | 33 | 25 | 11 | 1 | 0 |
| 26 | 31 | 33 | 25 | 10 | 1 | 0 |
| 27 | 34 | 33 | 24 | 9 | 1 | 0 |
| 28 | 36 | 33 | 23 | 8 | 1 | 0 |
| 29 | 39 | 33 | 21 | 7 | 0 | 0 |
| 30 | 41 | 32 | 20 | 6 | 0 | 0 |
Wind in September
Winds average 10 km/h in September.
Across September, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| 1 | 10 | calm |
| 2 | 10 | calm |
| 3 | 10 | calm |
| 4 | 10 | calm |
| 5 | 10 | calm |
| 6 | 10 | calm |
| 7 | 10 | calm |
| 8 | 10 | calm |
| 9 | 10 | calm |
| 10 | 10 | calm |
| 11 | 10 | calm |
| 12 | 10 | calm |
| 13 | 10 | calm |
| 14 | 10 | calm |
| 15 | 11 | calm |
| 16 | 11 | calm |
| 17 | 11 | calm |
| 18 | 11 | calm |
| 19 | 11 | calm |
| 20 | 11 | calm |
| 21 | 11 | calm |
| 22 | 11 | calm |
| 23 | 11 | calm |
| 24 | 11 | calm |
| 25 | 11 | calm |
| 26 | 11 | calm |
| 27 | 11 | calm |
| 28 | 11 | calm |
| 29 | 11 | calm |
| 30 | 11 | calm |
Sunrise & sunset in September
Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 66 minutes over September. Sunrise moves from 6:09 AM to 6:33 AM, and sunset from 6:59 PM to 6:14 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 12.8 | 12.8 | 12.7 | 12.7 | 12.7 | 12.6 | 12.6 | 12.6 | 12.5 | 12.5 | 12.4 | 12.4 | 12.4 | 12.3 | 12.3 | 12.2 | 12.2 | 12.2 | 12.1 | 12.1 | 12.0 | 12.0 | 11.9 | 11.9 | 11.9 | 11.8 | 11.8 | 11.7 | 11.7 | 11.7 |
| Sunrise (AM) | 6:09 | 6:10 | 6:11 | 6:12 | 6:12 | 6:13 | 6:14 | 6:15 | 6:16 | 6:17 | 6:17 | 6:18 | 6:19 | 6:20 | 6:21 | 6:22 | 6:22 | 6:23 | 6:24 | 6:25 | 6:26 | 6:27 | 6:27 | 6:28 | 6:29 | 6:30 | 6:31 | 6:32 | 6:33 | 6:33 |
| Sunset (PM) | 6:59 | 6:57 | 6:56 | 6:54 | 6:53 | 6:51 | 6:50 | 6:48 | 6:46 | 6:45 | 6:43 | 6:42 | 6:40 | 6:39 | 6:37 | 6:35 | 6:34 | 6:32 | 6:31 | 6:29 | 6:28 | 6:26 | 6:24 | 6:23 | 6:21 | 6:20 | 6:18 | 6:17 | 6:15 | 6:14 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 12.8 | 6:09 | 6:59 |
| 2 | 12.8 | 6:10 | 6:57 |
| 3 | 12.7 | 6:11 | 6:56 |
| 4 | 12.7 | 6:12 | 6:54 |
| 5 | 12.7 | 6:12 | 6:53 |
| 6 | 12.6 | 6:13 | 6:51 |
| 7 | 12.6 | 6:14 | 6:50 |
| 8 | 12.6 | 6:15 | 6:48 |
| 9 | 12.5 | 6:16 | 6:46 |
| 10 | 12.5 | 6:17 | 6:45 |
| 11 | 12.4 | 6:17 | 6:43 |
| 12 | 12.4 | 6:18 | 6:42 |
| 13 | 12.4 | 6:19 | 6:40 |
| 14 | 12.3 | 6:20 | 6:39 |
| 15 | 12.3 | 6:21 | 6:37 |
| 16 | 12.2 | 6:22 | 6:35 |
| 17 | 12.2 | 6:22 | 6:34 |
| 18 | 12.2 | 6:23 | 6:32 |
| 19 | 12.1 | 6:24 | 6:31 |
| 20 | 12.1 | 6:25 | 6:29 |
| 21 | 12.0 | 6:26 | 6:28 |
| 22 | 12.0 | 6:27 | 6:26 |
| 23 | 11.9 | 6:27 | 6:24 |
| 24 | 11.9 | 6:28 | 6:23 |
| 25 | 11.9 | 6:29 | 6:21 |
| 26 | 11.8 | 6:30 | 6:20 |
| 27 | 11.8 | 6:31 | 6:18 |
| 28 | 11.7 | 6:32 | 6:17 |
| 29 | 11.7 | 6:33 | 6:15 |
| 30 | 11.7 | 6:33 | 6:14 |
Solar energy in September
Average shortwave solar energy reaching the ground each day in September, about 4.38 kWh/m².
For context, solar energy here swings from a low near 2.15 kWh/m² to a high of 5.95 kWh/m² in May across the year — September's 4.38 kWh/m² falls in the middle.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.4 | 4.3 | 4.3 | 4.3 | 4.3 | 4.3 | 4.3 | 4.2 | 4.2 | 4.2 | 4.2 | 4.2 | 4.1 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 4.4 | Bright |
| 2 | 4.4 | Bright |
| 3 | 4.4 | Bright |
| 4 | 4.4 | Bright |
| 5 | 4.4 | Bright |
| 6 | 4.4 | Bright |
| 7 | 4.4 | Bright |
| 8 | 4.4 | Bright |
| 9 | 4.4 | Bright |
| 10 | 4.4 | Bright |
| 11 | 4.4 | Bright |
| 12 | 4.4 | Bright |
| 13 | 4.4 | Bright |
| 14 | 4.4 | Bright |
| 15 | 4.4 | Bright |
| 16 | 4.4 | Bright |
| 17 | 4.4 | Bright |
| 18 | 4.4 | Bright |
| 19 | 4.3 | Bright |
| 20 | 4.3 | Bright |
| 21 | 4.3 | Bright |
| 22 | 4.3 | Bright |
| 23 | 4.3 | Bright |
| 24 | 4.3 | Bright |
| 25 | 4.2 | Bright |
| 26 | 4.2 | Bright |
| 27 | 4.2 | Bright |
| 28 | 4.2 | Bright |
| 29 | 4.2 | Bright |
| 30 | 4.1 | Bright |
Hazard calendar for Seosan
In September, Seosan sits inside its pacific typhoon and rainy season season. The full year is below, with each hazard's peak months called out.
Seosan sits in the Pacific typhoon belt; the season peaks July–October.
Seosan's rainy season runs June–September, when most of the year's rain falls.
Is September a good time to visit Seosan?
Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
September is one of the better times to visit Seosan for general sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Seosan in September
From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In September, Seosan sees daytime highs around 25°C and nights near 18°C. Worth packing: light clothes. About 8 days see rain.
Sea temperature near Seosan in September
The nearest coast averages about 23°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 19 km away) is warmest in August at about 25°C and coldest in February near 5°C.
It's comfortable for a long swim from Jul 4 to Oct 7 — about 3.2 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 7 | 5 | 6 | 8 | 12 | 18 | 22 | 25 | 23 | 19 | 15 | 11 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Warm | Refreshing | Cool | Cool | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 7 | Bracing |
| Feb | 5 | Bracing |
| Mar | 6 | Bracing |
| Apr | 8 | Bracing |
| May | 12 | Bracing |
| Jun | 18 | Cool |
| Jul | 22 | Refreshing |
| Aug | 25 | Warm |
| Sep | 23 | Refreshing |
| Oct | 19 | Cool |
| Nov | 15 | Cool |
| Dec | 11 | Bracing |
UV index in Seosan in September
Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Seosan peaks around July 20 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. 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 | 6 | 7 | 8 | 7 | 7 | 5 | 3 | 2 |
| Level | Low | Moderate | Moderate | High | High | 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 | 6 | High |
| Jun | 7 | High |
| Jul | 8 | Very high |
| Aug | 7 | Very high |
| Sep | 7 | Very high |
| Oct | 5 | High |
| Nov | 3 | Moderate |
| Dec | 2 | Low |
Air quality in Seosan in September
Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.
Air quality in Seosan is worst in March — around 92 µg/m³ PM2.5 (unhealthy), about 2.0× the cleanest month (July, 46 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) | 83 | 85 | 92 | 75 | 62 | 57 | 46 | 47 | 61 | 74 | 79 | 73 |
| Level | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Poor | Poor | Unhealthy | Unhealthy | Unhealthy | Unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 83 | Unhealthy |
| Feb | 85 | Unhealthy |
| Mar | 92 | Unhealthy |
| Apr | 75 | Unhealthy |
| May | 62 | Unhealthy |
| Jun | 57 | Unhealthy |
| Jul | 46 | Poor |
| Aug | 47 | Poor |
| Sep | 61 | Unhealthy |
| Oct | 74 | Unhealthy |
| Nov | 79 | Unhealthy |
| Dec | 73 | Unhealthy |
Where is Seosan?
Seosan sits at 36.8°N, 126.5°E, 33 m above sea level, in South Korea. The nearest listed city is Tangjin, 20 km away.
Topography around Seosan
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Seosan.
Within 3 km, the terrain around Seosan has only modest variations in elevation — a maximum elevation change of 192 m around an average of 43 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 643 m; within 80 km, large variations in elevation — a maximum elevation change of 769 m.
The land around Seosan is covered by cropland (33%), trees (30%) and artificial surfaces (30%) within 3 km, cropland (39%) and trees (38%) within 16 km, and water (53%) and trees (25%) 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 Seosan (36.7817°, 126.4522°, elevation 33 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).