Climate Insights for Koesan

Goesan-gun, Chungcheongbuk-do, South Korea

Hottest
August
30°C peak
Coldest
January
-6°C low
Wettest
July
271mm rain
Best to Visit
May
Mild temps & low rain

Climate Overview

The climate in Koesan is temperate. The average annual temperature is 13°C and approximately 1165mm of precipitation falls per year. July is the wettest month, receiving around 271mm of rainfall. Koesan is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, June. The coldest months are January, December, February, when temperatures can drop to -6°C. Light snow can occur between January and December.

Temperature

-10° 10° 20° 30° Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Max: 3° Average: -2° Min: -6° Feb Max: 6° Average: 1° Min: -4° Mar Max: 13° Average: 7° Min: 2° Apr Max: 19° Average: 13° Min: 8° May Max: 24° Average: 18° Min: 13° Jun Max: 28° Average: 23° Min: 18° Jul Max: 29° Average: 25° Min: 22° Aug Max: 30° Average: 26° Min: 22° Sep Max: 26° Average: 21° Min: 17° Oct Max: 20° Average: 14° Min: 10° Nov Max: 12° Average: 7° Min: 3° Dec Max: 4° Average: 0° Min: -4°
Max
Average
Min

Koesan has a wide annual temperature range, spanning 36°C from the coldest to warmest months. The warmest month is August, when average highs reach 30°C and the mean temperature sits around 26°C. The coldest month is January, when overnight lows fall to -6°C and the daily average is -2°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs. The sharpest temperature change occurs between November and December, with a 7°C shift in average temperatures.

Precipitation

0mm 50mm 100mm 150mm 200mm 250mm 300mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Precipitation: 23mm Snow: 5mm Feb Precipitation: 37mm Snow: 5mm Mar Precipitation: 55mm Snow: 3mm Apr Precipitation: 78mm Snow: 0mm May Precipitation: 94mm Snow: 0mm Jun Precipitation: 104mm Snow: 0mm Jul Precipitation: 271mm Snow: 0mm Aug Precipitation: 206mm Snow: 0mm Sep Precipitation: 147mm Snow: 0mm Oct Precipitation: 70mm Snow: 0mm Nov Precipitation: 50mm Snow: 1mm Dec Precipitation: 30mm Snow: 4mm
Precipitation
Snow

Koesan is a moderately rainy area, receiving approximately 1165mm of precipitation annually, which averages out to around 97mm per month. The wettest month is July, averaging 271mm of rainfall. August and September also tend to see above-average precipitation. The driest month is January, with just 23mm. That's 248mm less than July, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Light snowfall can occur between January and December, totalling around 19cm annually. February is the snowiest month with approximately 5cm.

Wind

0km/h 5km/h 10km/h 15km/h 20km/h Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Wind Speed: 15km/h Feb Wind Speed: 16km/h Mar Wind Speed: 16km/h Apr Wind Speed: 16km/h May Wind Speed: 16km/h Jun Wind Speed: 13km/h Jul Wind Speed: 13km/h Aug Wind Speed: 12km/h Sep Wind Speed: 12km/h Oct Wind Speed: 13km/h Nov Wind Speed: 14km/h Dec Wind Speed: 15km/h
Wind Speed

Koesan is mildly breezy, with an average annual wind speed of 14km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 16km/h, though still comfortable for most outdoor activities. The calmest conditions occur in September, with average winds dropping to 12km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 4km/h between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 15km/h in winter, 16km/h in spring, 13km/h in summer, 13km/h in autumn.

Seasons

Winter
Dec 21
Spring
Mar 20
Summer
Jun 21
Autumn
Sep 23

89 days until Summer

It is currently spring in Koesan, which began on March 20, 2026. Koesan is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 30°C, while the coldest stretch bottoms out in January near -6°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

Spring

Temperatures range from 2 to 24°C. Precipitation is moderate at around 228mm for the season, averaging 76mm per month. Winds are moderate at around 16km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.

Summer

Temperatures range from 18 to 30°C. Rainfall is heavy, totalling around 581mm across the season with a monthly average of 194mm. Winds are generally light, averaging 13km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.

Autumn

Temperatures range from 3 to 26°C. Precipitation is moderate at around 266mm for the season, averaging 89mm per month. Winds are generally light, averaging 13km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.

Winter

Temperatures range from -6 to 6°C. Rainfall is relatively light, with around 91mm over the season and a monthly average of 30mm. Expect around 14cm of snow accumulation during this period. Winds are moderate at around 15km/h. Warm winter clothing and waterproof boots are a must, and travel may be affected by snow.

Best Time to Visit

Jan -2°
Feb
Mar
Apr 13°
May 18°
Jun 23°
Jul 25°
Aug 26°
Sep 21°
Oct 14°
Nov
Dec

The best time to visit Koesan is during May, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 94mm per month. By contrast, August can be uncomfortably hot with highs reaching 30°C, while January is the coldest period with lows dropping to -6°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

Monthly Climate Data

The table below shows monthly climate averages for Koesan based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.

Month
Min Temperature
Max Temperature
Wind Speed
Precipitation
Snow
Jan
-6 °C
3 °C
15 km/h
23 mm
5 cm
Feb
-4 °C
6 °C
16 km/h
37 mm
5 cm
Mar Current
2 °C
13 °C
16 km/h
55 mm
3 cm
Apr
8 °C
19 °C
16 km/h
78 mm
0 cm
May
13 °C
24 °C
16 km/h
94 mm
0 cm
Jun
18 °C
28 °C
13 km/h
104 mm
0 cm
Jul
22 °C
29 °C
13 km/h
271 mm
0 cm
Aug
22 °C
30 °C
12 km/h
206 mm
0 cm
Sep
17 °C
26 °C
12 km/h
147 mm
0 cm
Oct
10 °C
20 °C
13 km/h
70 mm
0 cm
Nov
3 °C
12 °C
14 km/h
50 mm
1 cm
Dec
-4 °C
4 °C
15 km/h
30 mm
4 cm
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Metric (°C, km/h)