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Gunsan weather by month: averages, rainfall & climate trends

Gunsan swings through a wide annual range, with 26.2°C between the monthly means of its warmest and coldest months. Rainfall is strongly seasonal: the bulk of the year's rain falls between June and September. Gunsan weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

−3.5°Chigh well below average

15° / 8°Today
19° / 12°Average
see today in detail →

How it's changed

+1.9°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4959frost days a year now (2016–2025) · 72 in the 1940sfrost days a year · 72 in the 1940s31days above 30°C a year now (2016–2025) · 4 in the 1940sdays above 30°C · 4 in the 1940s+1.9°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 35 mmhigh 3°low −3°February, rain 36 mmhigh 5°low −1°March, rain 53 mmhigh 9°low 3°April, rain 85 mmhigh 15°low 9°May, rain 95 mmhigh 20°low 14°June, rain 152 mmhigh 24°low 19°July, rain 273 mmhigh 27°low 23°August, rain 202 mmhigh 29°low 24°September, rain 147 mmhigh 25°low 19°October, rain 56 mmhigh 19°low 13°November, rain 52 mmhigh 13°low 6°December, rain 37 mmhigh 6°low 0°wettest month July, 273 mm · 1,222 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Partly cloudy

Right now

9.1°

7°feels like
69%humidity
4°dew point
2 km/hfrom E
UV index0.0
sunrise06:46sunset17:49day length11h 03m
ThuClear15°8°
FriPartly cloudy20°9°
SatLight rain17°15°
SunOvercast21°16°
MonLight rain19°17°
TuePartly cloudy18°7°
WedMostly clear13°4°

On this date: October 21

Today (forecast)
15° / 8°
Average for October 21
19° / 12°

High well below average · −3.5°C

  • Highest since 1940: 23.9° · 2006
  • Lowest since 1940: 6.1° · 1955
  • One year ago: 15° / 10°

Every October 21 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 21 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Gunsan is sampled from the ECMWF ERA5 reanalysis at 35.98°N, 126.71°E, with daily records since 1940.

Coordinates
35.98°N, 126.71°E
Time zone
Asia/Seoul
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

24 of the last 31 days were warmer than the historical average for that date. Average difference: +1.7°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

August brings the year's peak warmth, with afternoons typically reaching 28.8°C and nights around 24.2°C. Around 100 nights a year stay above 20°C. In January, the coolest month, afternoons reach about 3.1°C and nights dip to −3.0°C. Around 60 days a year dip below freezing.

In total, Gunsan averages about 1,222 mm of precipitation a year; July is usually the wettest month (273 mm) and January the driest (35 mm).

Over the full record (since 1940), the annual mean temperature in Gunsan has risen by 1.9°C between its first decade and its last. The count of days past 30°C has risen from roughly 4 a year to 30 between the record's first and last decades.

Climate graph (climograph)

August is the warmest month, January the coolest: a yearly swing of 26°C. Wettest month: July (~273 mm). Whole year averages ~1,222 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 82 rainy days a year: most in July (~13), fewest in February (~4).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Gunsan month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Highest and Lowest are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightHighestLowest
January3.1°−3.0°35 mm49.8 h14.9° (2002)−15.7° (1945)
February4.6°−1.5°36 mm410.7 h17.8° (2004)−13.3° (1963)
March9.2°3.3°53 mm511.7 h23.0° (2025)−7.4° (1977)
April15.4°9.3°85 mm612.9 h27.1° (1998)0.7° (1962)
May20.5°14.5°95 mm613.9 h28.9° (1991)7.6° (1947)
June24.2°19.2°152 mm814.4 h31.0° (2024)13.0° (1997)
July27.4°23.5°273 mm1314.2 h34.9° (2025)16.7° (1976)
August28.8°24.2°202 mm1213.4 h35.7° (1951)16.7° (1972)
September25.0°19.4°147 mm812.2 h33.9° (2024)10.6° (1957)
October19.3°12.7°56 mm411.1 h28.5° (2016)3.1° (1986)
November12.6°6.2°52 mm510.1 h24.2° (2011)−4.4° (1970)
December5.9°0.0°37 mm59.6 h18.4° (2004)−12.2° (1967)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +1.9°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.19°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Mar–May is warming fastest: +0.23°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 4.1 early in the record → 30.5 recently. Frost days: 72 → 59.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

Hottest day since 1940 in 1951, coldest in 1945: 35.7°C / −15.7°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~1,222 mm/year on average. Last decade: −1% vs that average. Long-term trend: +13 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Gunsan

Which is the warmest month in Gunsan?
On long-term average, the warmest month in Gunsan is August (mean daily temperature of about 26.4°C) and the coolest is January (about 0.2°C).
How does today's temperature in Gunsan compare to the historical average?
On October 21, 2026, Gunsan is forecast to reach a high of 15.1°C and a low of 7.8°C. The long-term average for this date (the full record since 1940) is a high of 18.6°C and a low of 11.8°C, so today's high is 3.5°C cooler than that average.
How much has Gunsan warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Gunsan is about 1.9°C warmer.
How much does it rain in Gunsan?
Gunsan receives about 1,222 mm of precipitation per year on long-term average, with July typically the wettest month.
What is the average temperature in Gunsan?
Over the full record (since 1940), the annual mean temperature in Gunsan is about 13.5°C. The warmest month is August and the coolest is January.
What are the average temperatures in Gunsan by month?
Average daily highs and lows for each month in Gunsan (°C, full record since 1940): January 3°/−3°, February 5°/−1°, March 9°/3°, April 15°/9°, May 20°/14°, June 24°/19°, July 27°/23°, August 29°/24°, September 25°/19°, October 19°/13°, November 13°/6°, December 6°/0°.
What is the weather like in Gunsan in summer?
In summer, June through August, Gunsan is wet and warm. It warms from 24°C by day and 19°C at night in June to 29°C and 24°C in August. Rain is steady at around 209 mm a month, spread over roughly 11 days. No season is wetter.
What is the weather like in Gunsan in winter?
In winter, December through February, Gunsan is cold. Daytime highs sit at 3–6°C and nights at −3 to 0°C; January is the coldest month. Rain and snow are steady at around 36 mm a month, spread over roughly 4 days. It is the driest season of the year.
What is the weather like in Gunsan in spring?
March to May is spring in Gunsan, and it is fairly mild. March starts at 9°C by day and 3°C at night; by May it is 20°C and 14°C. Rain rises from 53 mm on 5 days in March to 95 mm on 6 days in May.
What is the weather like in Gunsan in autumn?
September to November is autumn in Gunsan, and it is mild. September is still 25°C by day and 19°C at night; by November it is down to 13°C and 6°C. Rain eases through the season: 8 rainy days and 147 mm in September, 5 days and 52 mm in November.
How many days a year does it rain in Gunsan?
On long-term average, Gunsan has about 82 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,222 mm.

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