Seoul in May
What to expect
May in Seoul is late spring, a shoulder-season window, so you can get a bit of variety across the month. The month is warm and inviting for long walks, with a noticeable cool-down after sunset. There is plenty of daylight to stretch outdoor time. Most days feel close to what the averages suggest, with straightforward pacing.
May in context
How it compares to the rest of the year in Seoul.
Monthly climate breakdown
Temperature
- Daytime high
-
- Nighttime low
-
- Feels like (avg)
-
Sunshine
- Daylight hours
- 14.2 h
- UV index (max)
- 8
- Typical sun hours
- 05:22 - 19:34
Rain & Snow
- Total rain
-
- Rainy days
- 10 days
- Cloud cover (avg)
- 56%
Humidity & Wind
- Humidity (avg)
- 72%
- Wind (avg)
-
- Wind (max gusts)
-
Daily climate explorer
Day 15 selected for May. Typical high 21.3°C and low 12.2°C.
Typical disruptions in May
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in May.
Rain disruption Measures: Likely rain disruption days. Observed about 15% of days (4.7 days/month) in May. Historical risk signal only, not a day-by-day forecast.
4.7 days / month
~15% of days
Why this matters
- Expected days 4.7 days / month
- Probability ~15% of days
- Intensity Up to ~58mm (P95)
Rain disruption risk appears on ~5 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Washout risk Measures: Washout day risk. Observed about 14% of days (4.4 days/month) in May. Historical risk signal only, not a day-by-day forecast.
4.4 days / month
~14% of days
Why this matters
- Expected days 4.4 days / month
- Probability ~14% of days
- Intensity Up to ~59mm (P95)
Washout conditions are possible on ~4 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Stormy conditions Measures: Storm-impact proxy days. Observed about 4% of days (1.1 days/month) in May. Historical risk signal only, not a day-by-day forecast.
1.1 days / month
~4% of days
Why this matters
- Expected days 1.1 days / month
- Probability ~4% of days
- Intensity Up to ~80km/h (P95)
Stormy conditions are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 3% of days (1.0 days/month) in May. Historical risk signal only, not a day-by-day forecast.
1.0 days / month
~3% of days
Why this matters
- Expected days 1.0 days / month
- Probability ~3% of days
- Intensity Up to ~81km/h (P95)
Strong gusts are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Cold feels-like nights Measures: Cold feels-like nights (min <=5C). Observed about 7% of days (2.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
2.3 days / month
~7% of days
Why this matters
- Expected days 2.3 days / month
- Probability ~7% of days
- Intensity Up to ~5°C (P95)
Cold feels-like nights are possible on ~2 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 3% of days (0.9 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.9 days / month
~3% of days
Why this matters
- Expected days 0.9 days / month
- Probability ~3% of days
- Intensity Up to ~97% (P95)
Fog-likely conditions are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Show all disruptions (17 more)
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 9% of days (2.9 days/month) in May. Historical risk signal only, not a day-by-day forecast.
2.9 days / month
~9% of days
Why this matters
- Expected days 2.9 days / month
- Probability ~9% of days
- Intensity Up to ~61mm (P95)
Heavy rain is possible on ~3 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 4% of days (1.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
1.3 days / month
~4% of days
Why this matters
- Expected days 1.3 days / month
- Probability ~4% of days
- Intensity Up to ~68mm (P95)
Very heavy rain is possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Washout run Measures: Multi-day washout runs. Observed about 0.8 days/month in May. Historical risk signal only, not a day-by-day forecast.
0.8 days / month
Probability unavailable
Why this matters
- Expected days 0.8 days / month
- Probability —
- Intensity Up to ~61mm (P95)
Multi-day washout runs are possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Extreme rain Measures: Extreme rain days (>=50mm). Observed about 1% of days (0.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.3 days / month
~1% of days
Why this matters
- Expected days 0.3 days / month
- Probability ~1% of days
- Intensity Up to ~78mm (P95)
Extreme rain is possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Hot feels-like days Measures: Hot feels-like days (>=32C). Observed about 1% of days (0.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~34°C (P95)
Feels-like heat >=32C is possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 49% of days (15.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
15.2 days / month
~49% of days
Why this matters
- Expected days 15.2 days / month
- Probability ~49% of days
- Intensity Up to ~100% (P95)
Cloudy skies are possible on ~15 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Wet days Measures: Wet days (>=0.1mm). Observed about 38% of days (11.8 days/month) in May. Historical risk signal only, not a day-by-day forecast.
11.8 days / month
~38% of days
Why this matters
- Expected days 11.8 days / month
- Probability ~38% of days
- Intensity Up to ~37mm (P95)
Measurable rain is possible on ~12 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Gusty days Measures: Gusty days (>=40 km/h). Observed about 34% of days (10.6 days/month) in May. Historical risk signal only, not a day-by-day forecast.
10.6 days / month
~34% of days
Why this matters
- Expected days 10.6 days / month
- Probability ~34% of days
- Intensity Up to ~67km/h (P95)
Gusty conditions are possible on ~11 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 30% of days (9.5 days/month) in May. Historical risk signal only, not a day-by-day forecast.
9.5 days / month
~30% of days
Why this matters
- Expected days 9.5 days / month
- Probability ~30% of days
- Intensity Up to ~100% (P95)
Mostly cloudy skies are possible on ~9 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 28% of days (8.7 days/month) in May. Historical risk signal only, not a day-by-day forecast.
8.7 days / month
~28% of days
Why this matters
- Expected days 8.7 days / month
- Probability ~28% of days
- Intensity Up to ~21h (P95)
Several rainy hours are possible on ~9 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
High humidity Measures: High humidity days (RH >=80%). Observed about 24% of days (7.4 days/month) in May. Historical risk signal only, not a day-by-day forecast.
7.4 days / month
~24% of days
Why this matters
- Expected days 7.4 days / month
- Probability ~24% of days
- Intensity Up to ~94% (P95)
High humidity is possible on ~7 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 19% of days (5.9 days/month) in May. Historical risk signal only, not a day-by-day forecast.
5.9 days / month
~19% of days
Why this matters
- Expected days 5.9 days / month
- Probability ~19% of days
- Intensity Up to ~22h (P95)
Wet-most-of-day conditions are possible on ~6 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 16% of days (4.9 days/month) in May. Historical risk signal only, not a day-by-day forecast.
4.9 days / month
~16% of days
Why this matters
- Expected days 4.9 days / month
- Probability ~16% of days
- Intensity Up to ~100% (P95)
Overcast skies are possible on ~5 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 3% of days (0.9 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.9 days / month
~3% of days
Why this matters
- Expected days 0.9 days / month
- Probability ~3% of days
- Intensity Up to ~97 (P95)
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Convective risk Measures: Convective storm risk proxy. Observed about 1% of days (0.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~20°C (P95)
Convective risk signal appears on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humid days Measures: Humid days (dew point >=18C). Observed about 1% of days (0.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~20°C (P95)
Humid conditions are possible on ~0 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cold nights Measures: Cold nights (min <=5C). Observed about 1% of days (0.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~5°C (P95)
Cold nights are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Frequently asked questions
Is May a good time to visit Seoul?
Typical May days in Seoul reach highs of 22°C (72°F) with nights around 12°C (54°F). It usually feels warm by day and cool after dark. Overall, May sits in the middle of the Seoul climate range.
What are temperatures like in May?
Daytime temperatures in May typically peak near 22°C (72°F), while nights drop to around 12°C (54°F). Expect warm afternoons and cool evenings.
How much does it rain in May?
Rainfall in May averages 99 mm (3.9 in) across roughly 10 days. Overall it is a quite rainy time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in May?
You can expect about 14 hours of daylight in May. Sunrise is typically around 05:22 and sunset near 19:34. You get long days with comfortable amounts of daylight.
How strong is the sun in May?
UV levels frequently reach very high levels (around 8), so strong sun protection is essential, especially around midday.
Is it windy in May?
In May, average wind speeds are around 9 km/h (6 mph), with gusts on the windiest days reaching about 52 km/h (32 mph). On the ground, it is it can feel quite windy at times, particularly when weather systems move through.