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Suwon weather by month: averages, rainfall & climate trends

Suwon swings through a wide annual range, with 28.1°C between the monthly means of its warmest and coldest months. Most of the year's rain is packed into the months from June to September. Suwon weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

+1.1°Chigh near average

20° / 10°Today
19° / 9°Average
see today in detail →

How it's changed

+2.3°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4996frost days a year now (2016–2025) · 118 in the 1940sfrost days a year · 118 in the 1940s42days above 30°C a year now (2016–2025) · 15 in the 1940sdays above 30°C · 15 in the 1940s+2.3°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 27 mmhigh 1°low −7°February, rain 28 mmhigh 4°low −4°March, rain 46 mmhigh 10°low 1°April, rain 79 mmhigh 17°low 7°May, rain 87 mmhigh 22°low 12°June, rain 133 mmhigh 26°low 18°July, rain 286 mmhigh 28°low 22°August, rain 215 mmhigh 29°low 22°September, rain 140 mmhigh 25°low 17°October, rain 51 mmhigh 19°low 9°November, rain 49 mmhigh 12°low 3°December, rain 30 mmhigh 4°low −4°wettest month July, 286 mm · 1,171 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Mostly clear

Right now

10.9°

10°feels like
87%humidity
9°dew point
1 km/hfrom E
UV index0.0
sunrise06:44sunset17:49day length11h 05m
TueOvercast20°10°
WedMostly clear16°6°
ThuClear14°4°
FriPartly cloudy20°5°
SatOvercast20°13°
SunOvercast20°14°
MonLight rain19°16°

On this date: October 19

Today (forecast)
20° / 10°
Average for October 19
19° / 9°

High near average · +1.1°C

  • Highest since 1940: 25.3° · 1951
  • Lowest since 1940: −3.0° · 1956
  • One year ago: 20° / 6°

Every October 19 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 19 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 Suwon is sampled from the ECMWF ERA5 reanalysis at 37.29°N, 127.01°E, with daily records since 1940.

Coordinates
37.29°N, 127.01°E
Time zone
Asia/Seoul
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

26 of the last 31 days were warmer than the historical average for that date. Average difference: +2.1°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

The year peaks in August, at around 29.1°C by mid-afternoon, with nights around 22.5°C. On about 75 nights a year, the temperature never drops below 20°C. At the other extreme, January brings afternoon highs of about 1.4°C and typical overnight lows of −6.9°C. Frost shows up on around 95 mornings a year.

Suwon picks up roughly 1,171 mm a year, with a peak of 286 mm in July and as little as 27 mm in January.

Over the full record (since 1940), the annual mean temperature in Suwon has risen by 2.3°C between its first decade and its last. The count of days past 30°C has risen from roughly 15 a year to 40 between the record's first and last decades.

Climate graph (climograph)

August is the warmest month, January the coolest: a yearly swing of 28°C. Wettest month: July (~286 mm). Whole year averages ~1,171 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 78 rainy days a year: most in July (~14), fewest in January (~3).

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.

Suwon 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
January1.4°−6.9°27 mm39.7 h14.9° (2002)−22.3° (1941)
February4.0°−4.4°28 mm310.6 h18.5° (2021)−20.4° (1969)
March9.7°0.6°46 mm511.7 h25.3° (2025)−14.4° (1969)
April16.8°6.7°79 mm613.0 h29.0° (2005)−3.0° (1941)
May22.2°12.3°87 mm614.0 h31.4° (2019)4.3° (1978)
June25.9°17.6°133 mm714.6 h35.1° (2024)9.3° (1981)
July28.2°22.2°286 mm1414.3 h36.6° (2025)13.5° (1941)
August29.1°22.5°215 mm1213.4 h38.0° (2018)13.7° (1972)
September25.2°16.8°140 mm712.2 h33.6° (2024)5.9° (1956)
October19.3°9.4°51 mm411.0 h28.9° (2006)−3.1° (1986)
November11.6°2.6°49 mm610.0 h25.5° (2023)−10.5° (1996)
December4.1°−4.0°30 mm49.4 h17.6° (2023)−19.0° (2000)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +2.3°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: +0.23°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: +0.28°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: 14.9 early in the record → 41.5 recently. Frost days: 118 → 96.

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 2018, coldest in 1941: 38.0°C / −22.3°C.

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

Annual rainfall

~1,171 mm/year on average. Last decade: −1% vs that average. Long-term trend: +15 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 Suwon

Which is the warmest month in Suwon?
On long-term average, the warmest month in Suwon is August (mean daily temperature of about 25.5°C) and the coolest is January (about −2.6°C).
How does today's temperature in Suwon compare to the historical average?
On October 19, 2026, Suwon is forecast to reach a high of 20.4°C and a low of 9.9°C. The long-term average for this date (the full record since 1940) is a high of 19.3°C and a low of 8.8°C, so today's high is 1.1°C warmer than that average.
How much has Suwon warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Suwon is about 2.3°C warmer.
How much does it rain in Suwon?
Suwon receives about 1,171 mm of precipitation per year on long-term average, with July typically the wettest month.
What is the average temperature in Suwon?
Over the full record (since 1940), the annual mean temperature in Suwon is about 12.1°C. The warmest month is August and the coolest is January.
What are the average temperatures in Suwon by month?
Average daily highs and lows for each month in Suwon (°C, full record since 1940): January 1°/−7°, February 4°/−4°, March 10°/1°, April 17°/7°, May 22°/12°, June 26°/18°, July 28°/22°, August 29°/22°, September 25°/17°, October 19°/9°, November 12°/3°, December 4°/−4°.
What is the weather like in Suwon in summer?
In summer, June through August, Suwon is wet and warm. Daytime highs sit at 26–29°C and nights at 18–22°C; August is the warmest month. Rain rises from 133 mm on 7 days in June to 215 mm on 12 days in August. It is the wettest season of the year.
What is the weather like in Suwon in winter?
In winter, December through February, Suwon is cold. Afternoons run 1–4°C and nights −7 to −4°C; January is the coldest month. Rain and snow are steady at around 29 mm a month, spread over roughly 4 days. It is the driest season of the year.
What is the weather like in Suwon in spring?
March to May is spring in Suwon, and it is fairly mild. March starts at 10°C by day and 1°C at night; by May it is 22°C and 12°C. Rain rises from 46 mm on 5 days in March to 87 mm on 6 days in May.
What is the weather like in Suwon in autumn?
Autumn in Suwon (September to November) is mild. September is still 25°C by day and 17°C at night; by November it is down to 12°C and 3°C. Rain falls off from 140 mm on 7 days in September to 49 mm on 6 days in November.
How many days a year does it rain in Suwon?
On long-term average, Suwon has about 78 days a year with at least 2 mm of rain or snow. The annual total is roughly 1,171 mm.

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