Ulsan climate

Name: Ulsan
Address: KR

Ulsan is warmest in August, with average highs of 28 °C, and coldest in January, when nights average -1.4 °C. July is the wettest month (222 mm) and December the driest (28 mm). Figures are 1991–2020 climate normals.

Across a full year Ulsan averages 1,246 mm of rain, 81 days above 25 °C and 56 days below freezing.

South Korea · population 1,098,421 · 1991–2020 normals

Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month

Warmest month August 28 °C
Coldest month January -1.4 °C
Driest month December 28 mm
Wettest month July 222 mm
Least cloud December 35 % cloud
Hottest on record August 38 °C
Coldest on record January -13 °C
Warmest sea August 26 °C

What to expectUlsan through the year

Ulsan has a clear annual cycle: average daily highs run from 5.9 °C in January to 28 °C in August, a swing of 24 °C in mean temperature across the year.

Counted across a normal year, 81 days a year reach 25 °C, 18 of them reach 30 °C, 56 nights drop below freezing. The warmest reading in the 1991–2020 record is 38 °C, in August.

Rain is strongly seasonal. July averages 222 mm against 28 mm in December — 8.1 times as much. Planning around the dry months matters more here than planning around temperature.

The sea off Ulsan is warmest in August at 26 °C and coldest in February at 14 °C. Sea temperature lags the air by a month or two, which is why late summer swims warmer than early summer at the same air temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	5.9 °C	33 mm	40 %
February	8.1 °C	39 mm	47 %
March	12.3 °C	71 mm	53 %
April	17.3 °C	92 mm	55 %
May	21.7 °C	100 mm	59 %
June	24.6 °C	152 mm	71 %
July	27.4 °C	222 mm	73 %
August	28.4 °C	215 mm	66 %
September	24.5 °C	174 mm	63 %
October	20.1 °C	75 mm	47 %
November	14.2 °C	46 mm	40 %
December	7.9 °C	28 mm	35 %

Temperature month by month

Month	Avg high	Avg low	Mean	Record high	Record low	Days above 25 °C	Days above 30 °C	Days below 0 °C
January	5.9 °C	-1.4 °C	2.0 °C	16.1 °C	-13.1 °C	0	0	21
February	8.1 °C	0.1 °C	3.8 °C	19.7 °C	-12.4 °C	0	0	15
March	12.3 °C	3.7 °C	7.8 °C	22.6 °C	-5.4 °C	0	0	4
April	17.3 °C	8.4 °C	12.7 °C	28.4 °C	-1.0 °C	0	0	0
May	21.7 °C	13.2 °C	17.3 °C	35.4 °C	5.1 °C	4	0	0
June	24.6 °C	17.8 °C	21.0 °C	34.7 °C	11.6 °C	13	1	0
July	27.4 °C	22.3 °C	24.6 °C	37.2 °C	14.8 °C	24	7	0
August	28.4 °C	23.4 °C	25.6 °C	37.9 °C	16.9 °C	26	9	0
September	24.5 °C	19.2 °C	21.7 °C	33.6 °C	9.5 °C	12	1	0
October	20.1 °C	13.2 °C	16.5 °C	27.5 °C	1.8 °C	1	0	0
November	14.2 °C	6.5 °C	10.1 °C	22.7 °C	-4.5 °C	0	0	2
December	7.9 °C	0.4 °C	3.8 °C	19.8 °C	-10.1 °C	0	0	15

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	33 mm	4	10 h/day	40 %	57 %	19 km/h	14.8 °C
February	39 mm	5	11 h/day	47 %	58 %	19 km/h	13.7 °C
March	71 mm	7	12 h/day	53 %	63 %	19 km/h	13.8 °C
April	92 mm	8	13 h/day	55 %	67 %	19 km/h	14.8 °C
May	100 mm	8	14 h/day	59 %	73 %	17 km/h	16.7 °C
June	152 mm	9	15 h/day	71 %	81 %	17 km/h	20.0 °C
July	222 mm	13	14 h/day	73 %	86 %	18 km/h	23.0 °C
August	215 mm	14	14 h/day	66 %	84 %	17 km/h	26.0 °C
September	174 mm	11	12 h/day	63 %	80 %	17 km/h	24.6 °C
October	75 mm	5	11 h/day	47 %	72 %	17 km/h	22.0 °C
November	46 mm	5	10 h/day	40 %	67 %	17 km/h	19.5 °C
December	28 mm	3	9.8 h/day	35 %	60 %	18 km/h	16.9 °C

How Ulsan compares

The same four figures for nearby destinations, so the numbers above have something to be read against. Summer high is the warmest month's average high; winter low is the coldest month's average low.

Destination	Summer high	Winter low	Rain per year	Days above 25 °C
Ulsan	28 °C	-1.4 °C	1,246 mm	81
Gyeongju · South Korea	29 °C	-2.8 °C	1,135 mm	104
Pohang · South Korea	29 °C	-1.8 °C	1,091 mm	86
Busan · South Korea	28 °C	-0.06 °C	1,329 mm	62
Gyeongsan-si · South Korea	30 °C	-3.3 °C	1,055 mm	114
Changwon · South Korea	29 °C	-1.5 °C	1,323 mm	92
Daegu · South Korea	30 °C	-3.4 °C	1,089 mm	114

Planning a trip? See the best time to visit Ulsan.

QuestionsCommon questions about Ulsan’s climate

When is the best time to visit Ulsan?

That depends on what you want, so the honest answer is a comparison rather than a single month. May, June, September sit closest to 20 °C on average, August is the warmest month and December the driest. The month-by-month table above has the full picture.

How hot does Ulsan get?

In August, the warmest month, daily highs average 28 °C. About 18 days a year pass 30 °C. The highest value in the 1991–2020 record is 38 °C.

How cold does it get in winter?

Nights average -1.4 °C in January, the coldest month. A normal year has 56 nights below freezing.

Which month is wettest in Ulsan?

July, averaging 222 mm over 13 days with rain. The driest month is December with 28 mm. The year as a whole averages 1,246 mm.

Are these figures a forecast?

No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Ulsan rather than what any particular week will bring. Individual years can differ substantially from the normal.

Data sources and method

ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
Open-Meteo — Open-Meteo.com. CC BY 4.0
NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
GeoNames — GeoNames.org. CC BY 4.0

Normal period: 1991–2020
Dataset version: era5-1991-2020-scores1.1
Last processed: 1 August 2026

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.