January 2° · ☂ 3 February 5° · ☂ 3 March 12° · ☂ 5 April 18° · ☂ 7 ★ May23° · ☂ 7 June 28° · ☂ 7 July 30° · ☂ 14 August 30° · ☂ 11 ★ September27° · ☂ 7 October 20° · ☂ 6 November 12° · ☂ 6 December 4° · ☂ 5 Seoul in September:warm, Seoul, South Korea · Records from 2006 to 2025. Not a forecast.
Mean high 27° Hottest day 34.5° (2024)
Mean low 18° Coldest night 7.4° (2010)
Rain days 7 days 2-17 by year
Rainfall 146mm Daylight 13.0 → 11.9 h
Seoul's 12 months i Best: May and September
1 2 3 4 5 6 7 8 9 10 11 12
Trip types Sightseeing on foot Finemild and storm risk
Humidity 77% 6 muggy days
Clear days 6 days 10 overcast days
Mean wind 8 km/h Rarely windy
Sunrise / sunset (15th) 06:13 / 18:41 Daylight 13.0 → 11.9 h
Seoul in September Mornings and evenings cool down, but the afternoons stay warm. A short autumn rainy spell often passes in late August to early September, and some years a typhoon brings wind and rain. Chuseok is the 15th day of the 8th lunar month, between early September and early October. In recent years the four main palaces and Jongmyo Shrine have opened free over the holiday.
Daytime highs averaged 27°C, with nights at 18°C. Comfortably warm without being punishing. Out of 30 days, about 7 brought rain; the rest stayed dry. It varied a lot from year to year. September 2009 had 2 rain days; 2007 had 17.
Highs passed 30°C on 3 days on average. Not every year was typical: 2024 ran 2.5°C warmer than the mean, with highs of 29.0°C. Rain days averaged 21 mm each, so when it rained it rained properly.
How long it rained On a rainy day it rained for about 7.0 hours. Rain came at any time of day.
0 3 6 9 12 15 18 21
Typhoons i 5 of the last 20 years had a tropical storm pass within 300 km this month.
Kompasu (2010), 62 km away typhoon strength Lingling (2019), 161 km away typhoon strength Sanba (2012), 169 km away typhoon strength 1 2 3 4 5 6 3 7 6 8 5 9 2 10 11 12
Date by date i Sun
Mon
Tue
Wed
Thu
Fri
Sat
Week
September 1 Wednesday 1 rain in 6 of 20 yrs 6/20 28° 20° September 2 Thursday 2 rain in 7 of 20 yrs 7/20 28° 20° September 3 Friday 3 rain in 3 of 20 yrs 3/20 28° 21° September 4 Saturday 4 rain in 6 of 20 yrs 6/20 28° 21° 1-4 rain on 28% of days 28° 20°
September 5 Sunday 5 rain in 8 of 20 yrs 8/20 27° 20° September 6 Monday 6 rain in 8 of 20 yrs 8/20 27° 20° September 7 Tuesday 7 rain in 4 of 20 yrs 4/20 28° 19° September 8 Wednesday 8 rain in 2 of 20 yrs 2/20 28° 19° September 9 Thursday 9 rain in 6 of 20 yrs 6/20 27° 19° September 10 Friday 10 rain in 4 of 20 yrs 4/20 28° 19° September 11 Saturday 11 rain in 6 of 20 yrs 6/20 27° 19° 5-11 rain on 27% of days 27° 19°
September 12 Sunday 12 rain in 5 of 20 yrs 5/20 27° 19° September 13 Monday 13 rain in 5 of 20 yrs 5/20 27° 19° September 14 Tuesday 14 rain in 4 of 20 yrs 4/20 27° 19° September 15 Wednesday 15 rain in 2 of 20 yrs 2/20 28° 20° September 16 Thursday 16 rain in 7 of 20 yrs 7/20 27° 19° September 17 Friday 17 rain in 9 of 20 yrs 9/20 27° 19° September 18 Saturday 18 rain in 4 of 20 yrs 4/20 27° 18° 12-18 rain on 26% of days 27° 19°
September 19 Sunday 19 rain in 5 of 20 yrs 5/20 27° 18° September 20 Monday 20 rain in 7 of 20 yrs 7/20 25° 17° September 21 Tuesday 21 rain in 7 of 20 yrs 7/20 25° 17° September 22 Wednesday 22 rain in 4 of 20 yrs 4/20 25° 16° September 23 Thursday 23 rain in 3 of 20 yrs 3/20 26° 16° September 24 Friday 24 rain in 4 of 20 yrs 4/20 26° 15° September 25 Saturday 25 rain in 0 of 20 yrs 0/20 26° 16° 19-25 rain on 21% of days 26° 17°
September 26 Sunday 26 rain in 1 of 20 yrs 1/20 26° 16° September 27 Monday 27 rain in 5 of 20 yrs 5/20 25° 16° September 28 Tuesday 28 rain in 3 of 20 yrs 3/20 24° 16° September 29 Wednesday 29 rain in 4 of 20 yrs 4/20 24° 15° September 30 Thursday 30 rain in 2 of 20 yrs 2/20 24° 15°
26-30 rain on 15% of days 25° 16°
1-4 rain on 28% of days 28° 20° 5-11 rain on 27% of days 27° 19° 12-18 rain on 26% of days 27° 19° 19-25 rain on 21% of days 26° 17° 26-30 rain on 15% of days 25° 16°
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Week
September 1 Friday 1 rain in 6 of 20 yrs 6/20 28° 20° September 2 Saturday 2 rain in 7 of 20 yrs 7/20 28° 20° 1-2 rain on 33% of days 28° 20°
September 3 Sunday 3 rain in 3 of 20 yrs 3/20 28° 21° September 4 Monday 4 rain in 6 of 20 yrs 6/20 28° 21° September 5 Tuesday 5 rain in 8 of 20 yrs 8/20 27° 20° September 6 Wednesday 6 rain in 8 of 20 yrs 8/20 27° 20° September 7 Thursday 7 rain in 4 of 20 yrs 4/20 28° 19° September 8 Friday 8 rain in 2 of 20 yrs 2/20 28° 19° September 9 Saturday 9 rain in 6 of 20 yrs 6/20 27° 19° 3-9 rain on 26% of days 28° 20°
September 10 Sunday 10 rain in 4 of 20 yrs 4/20 28° 19° September 11 Monday 11 rain in 6 of 20 yrs 6/20 27° 19° September 12 Tuesday 12 rain in 5 of 20 yrs 5/20 27° 19° September 13 Wednesday 13 rain in 5 of 20 yrs 5/20 27° 19° September 14 Thursday 14 rain in 4 of 20 yrs 4/20 27° 19° September 15 Friday 15 rain in 2 of 20 yrs 2/20 28° 20° September 16 Saturday 16 rain in 7 of 20 yrs 7/20 27° 19° 10-16 rain on 24% of days 27° 19°
September 17 Sunday 17 rain in 9 of 20 yrs 9/20 27° 19° September 18 Monday 18 rain in 4 of 20 yrs 4/20 27° 18° September 19 Tuesday 19 rain in 5 of 20 yrs 5/20 27° 18° September 20 Wednesday 20 rain in 7 of 20 yrs 7/20 25° 17° September 21 Thursday 21 rain in 7 of 20 yrs 7/20 25° 17° September 22 Friday 22 rain in 4 of 20 yrs 4/20 25° 16° September 23 Saturday 23 rain in 3 of 20 yrs 3/20 26° 16° 17-23 rain on 28% of days 26° 17°
September 24 Sunday 24 rain in 4 of 20 yrs 4/20 26° 15° September 25 Monday 25 rain in 0 of 20 yrs 0/20 26° 16° September 26 Tuesday 26 rain in 1 of 20 yrs 1/20 26° 16° September 27 Wednesday 27 rain in 5 of 20 yrs 5/20 25° 16° September 28 Thursday 28 rain in 3 of 20 yrs 3/20 24° 16° September 29 Friday 29 rain in 4 of 20 yrs 4/20 24° 15° September 30 Saturday 30 rain in 2 of 20 yrs 2/20 24° 15° 24-30 rain on 14% of days 25° 16°
1-2 rain on 33% of days 28° 20° 3-9 rain on 26% of days 28° 20° 10-16 rain on 24% of days 27° 19° 17-23 rain on 28% of days 26° 17° 24-30 rain on 14% of days 25° 16°
Tap another date to change
2006 3mm
2007 41mm
2008 none
2009 none
2010 none
2011 8mm
2012 123mm
2013 none
2014 none
2015 none
2016 10mm
2017 none
2018 none
2019 none
2020 none
2021 none
2022 1mm
2023 8mm
2024 3mm
2025 22mm
Holidays in September (2027) September 14 to September 16 Chuseok (Korean Thanksgiving) holidaySeptember 14 to September 16 Chuseok breakSeptember 6 Labor Day 1 Local public holiday or break (busier, pricier)1 US holidays (flights fill up)
Day by day temperature i 14° 21° 29° 36° 1 8 15 22 29 30
Your trip dates, the past 20 years Trip dates September 1 (Wed) 2 (Thu) 3 (Fri) 4 (Sat) 5 (Sun) 6 (Mon) 7 (Tue) 8 (Wed) 9 (Thu) 10 (Fri) 11 (Sat) 12 (Sun) 13 (Mon) 14 (Tue) 15 (Wed) 16 (Thu) 17 (Fri) 18 (Sat) 19 (Sun) 20 (Mon) 21 (Tue) 22 (Wed) 23 (Thu) 24 (Fri) 25 (Sat) 26 (Sun) 27 (Mon) 28 (Tue) 29 (Wed) 30 (Thu) ~ September 1 (Wed) 2 (Thu) 3 (Fri) 4 (Sat) 5 (Sun) 6 (Mon) 7 (Tue) 8 (Wed) 9 (Thu) 10 (Fri) 11 (Sat) 12 (Sun) 13 (Mon) 14 (Tue) 15 (Wed) 16 (Thu) 17 (Fri) 18 (Sat) 19 (Sun) 20 (Mon) 21 (Tue) 22 (Wed) 23 (Thu) 24 (Fri) 25 (Sat) 26 (Sun) 27 (Mon) 28 (Tue) 29 (Wed) 30 (Thu) 1-7 8-14 15-21 22-end Whole month
You can also click two dates on the axis. Hover a cell to see that day's rain. By year Driest trips first
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
Trip rain days Month rain days Tap a date to start, tap another to end. Each cell is that date in one year. '06 '07 '08 '09 '10 '11 '12 '13 '14 '15 '16 '17 '18 '19 '20 '21 '22 '23 '24 '25
of 20 10 Fri Pick September 10
4 11 Sat Pick September 11
6 12 Sun Pick September 12
5 13 Mon Pick September 13
5 14 Tue Pick September 14
4 15 Wed Pick September 15
2 16 Thu Pick September 16
7 17 Fri Pick September 17
9 18 Sat Pick September 18
4 19 Sun Pick September 19
5 20 Mon Pick September 20
7 21 Tue Pick September 21
7 22 Wed Pick September 22
4 23 Thu Pick September 23
3 24 Fri Pick September 24
4 25 Sat Pick September 25
0 26 Sun Pick September 26
1 27 Mon Pick September 27
5 28 Tue Pick September 28
3 29 Wed Pick September 29
4 30 Thu Pick September 30
2 Dates outside your trip are dimmed.
One row per year, one cell per day. 2009 had 2 rain days, 2007 had 17.
Common questions Does it rain a lot in Seoul in September? Over the past 20 years September averaged 7 rain days (1 mm or more) out of 30. Individual years ran from 2 in the driest to 17 in the wettest.
What should I wear in Seoul in September? Days averaged 27°C and nights 18°C. Pack a compact umbrella, T-shirts, a light layer for the evenings, and sunscreen plus a hat.
Is September a good time to visit Seoul? On warmth and rain days alone, Seoul's easiest months were May and September. September ranked 2 of 12, close to the top.
Is Seoul humid in September? Mean relative humidity was 77%, with about 6 muggy days (dew point of 20°C or more) in the month.
Previous month Seoul in August Next month Seoul in October Whole year Seoul weather by month Where to go September By country South Korea: all cities this month Compare Compare with Busan Compare Compare with Tokyo