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Climate and Average Weather Year Round in Incheon South Korea

In Incheon, the summers are warm, muggy, wet, and partly cloudy and the winters are short, freezing, dry, windy, and mostly clear. Over the course of the year, the temperature typically varies from 19°F to 85°F and is rarely below 8°F or above 91°F.

Based on the tourism score, the best times of year to visit Incheon for warm-weather activities are from late May to mid July and from mid August to late September.

Climate in Incheon

very coldcoldcoolwarmcoolcoldJanFebMarAprMayJunJulAugSepOctNovDecNowNow72%72%45%45%clearovercastprecipitation: 11.0 inprecipitation: 11.0 in0.6 in0.6 inmuggy: 93%muggy: 93%0%0%drydrytourism score: 6.8tourism score: 6.80.00.0
Incheon weather by month. Click on each chart for more information.

Average Temperature in Incheon

The warm season lasts for 3.8 months, from May 30 to September 25, with an average daily high temperature above 75°F. The hottest day of the year is August 4, with an average high of 85°F and low of 73°F.

The cold season lasts for 3.0 months, from December 2 to March 1, with an average daily high temperature below 44°F. The coldest day of the year is January 18, with an average low of 19°F and high of 33°F.

Average High and Low Temperature in Incheon

Average High and Low Temperature in IncheonwarmcoldcoldJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FJan 1833°FJan 1833°FAug 485°FAug 485°F19°F19°F73°F73°FMay 3075°FMay 3075°FSep 2575°FSep 2575°FDec 244°FDec 244°FMar 144°FMar 144°F59°F59°F59°F59°F30°F30°F28°F28°FNowNow
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in Incheon

Average Hourly Temperature in IncheonJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNowNowfreezingfreezingvery coldcoldcoldcoolcoolcomfortablewarmvery coldfreezingwarmfreezing
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Chicago, Illinois, United States (6,552 miles away) is the far-away foreign place with temperatures most similar to Incheon (view comparison).

Compare Incheon to another city:

Clouds

In Incheon, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Incheon begins around September 11 and lasts for 5.9 months, ending around March 7. On October 20, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 72% of the time, and overcast or mostly cloudy 28% of the time.

The cloudier part of the year begins around March 7 and lasts for 6.1 months, ending around September 11. On July 14, the cloudiest day of the year, the sky is overcast or mostly cloudy 55% of the time, and clear, mostly clear, or partly cloudy 45% of the time.

Cloud Cover Categories in Incheon

Cloud Cover Categories in IncheonclearerclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Oct 2072%Oct 2072%Jul 1445%Jul 1445%Sep 1158%Sep 1158%Mar 759%Mar 759%NowNowclearovercastmostly cloudypartly cloudymostly clear
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Incheon varies significantly throughout the year.

The wetter season lasts 2.8 months, from June 19 to September 12, with a greater than 30% chance of a given day being a wet day. The chance of a wet day peaks at 52% on July 22.

The drier season lasts 9.2 months, from September 12 to June 19. The smallest chance of a wet day is 9% on January 22.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 52% on July 22.

Daily Chance of Precipitation in Incheon

Daily Chance of Precipitation in IncheonwetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jul 2252%Jul 2252%Jan 229%Jan 229%Jan 19%Jan 19%Jun 1930%Jun 1930%Sep 1230%Sep 1230%NowNowrainsnow
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Incheon experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 11 months, from January 27 to December 29, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around July 17, with an average total accumulation of 11.0 inches.

The rainless period of the year lasts for 4.1 weeks, from December 29 to January 27. The least rain falls around January 16, with an average total accumulation of 0.4 inches.

Average Monthly Rainfall in Incheon

Average Monthly Rainfall in IncheonrainJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in5 in5 in10 in10 in15 in15 in20 in20 inJul 1711.0 inJul 1711.0 inJan 160.4 inJan 160.4 inDec 290.5 inDec 290.5 inNowNow
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

The sliding 31-day liquid-equivalent quantity of snowfall in Incheon does not vary significantly over the course of the year, staying within 0.1 inches of 0.1 inches throughout.

Average Liquid-Equivalent Monthly Snowfall in Incheon

Average Liquid-Equivalent Monthly Snowfall in IncheonsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 in12 in12 inJan 230.1 inJan 230.1 inJul 160.0 inJul 160.0 inDec 250.1 inDec 250.1 inNowNow
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in Incheon varies significantly over the course of the year. In 2021, the shortest day is December 22, with 9 hours, 35 minutes of daylight; the longest day is June 21, with 14 hours, 45 minutes of daylight.

Hours of Daylight and Twilight in Incheon

Hours of Daylight and Twilight in IncheonJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 8 minMar 2012 hr, 8 minMar 2014 hr, 45 minJun 2114 hr, 45 minJun 2112 hr, 10 minSep 2312 hr, 10 minSep 239 hr, 35 minDec 229 hr, 35 minDec 22nightnightdayNowNow
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:11 AM on June 13, and the latest sunrise is 2 hours, 36 minutes later at 7:48 AM on January 6. The earliest sunset is at 5:14 PM on December 7, and the latest sunset is 2 hours, 43 minutes later at 7:58 PM on June 28.

Daylight saving time (DST) is not observed in Incheon during 2021.

Sunrise & Sunset with Twilight in Incheon

Sunrise & Sunset with Twilight in IncheonJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 135:11 AMJun 135:11 AM7:58 PMJun 287:58 PMJun 28Dec 75:14 PMDec 75:14 PM7:48 AMJan 67:48 AMJan 6daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2021. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

Moon

The figure below presents a compact representation of key lunar data for 2021. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

Moon Rise, Set & Phases in Incheon

The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Incheon experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.1 months, from June 15 to September 17, during which time the comfort level is muggy, oppressive, or miserable at least 23% of the time. The muggiest day of the year is August 4, with muggy conditions 93% of the time.

The least muggy day of the year is December 6, when muggy conditions are essentially unheard of.

Humidity Comfort Levels in Incheon

Humidity Comfort Levels in IncheonmuggyJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Dec 60%Dec 60%93%Aug 493%Aug 4Jun 1523%Jun 1523%Sep 1723%Sep 1723%NowNowoppressiveoppressivedrydrymuggymuggymiserablemiserablecomfortablecomfortable
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Incheon experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.7 months, from October 20 to May 10, with average wind speeds of more than 9.0 miles per hour. The windiest day of the year is December 25, with an average hourly wind speed of 10.9 miles per hour.

The calmer time of year lasts for 5.3 months, from May 10 to October 20. The calmest day of the year is June 14, with an average hourly wind speed of 7.1 miles per hour.

Average Wind Speed in Incheon

Average Wind Speed in IncheonwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mph16 mph16 mph18 mph18 mphDec 2510.9 mphDec 2510.9 mphJun 147.1 mphJun 147.1 mphOct 209.0 mphOct 209.0 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Incheon varies throughout the year.

The wind is most often from the west for 4.4 months, from February 25 to July 7, with a peak percentage of 44% on April 9. The wind is most often from the east for 1.6 months, from August 12 to September 29, with a peak percentage of 36% on September 8. The wind is most often from the north for 4.9 months, from September 29 to February 25, with a peak percentage of 54% on January 1.

Wind Direction in Incheon

Wind Direction in IncheonNWSENJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

Incheon is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences significant seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.1 months, from July 6 to October 9, with an average temperature above 68°F. The day of the year with the warmest water is August 21, with an average temperature of 76°F.

The time of year with cooler water lasts for 3.7 months, from December 24 to April 15, with an average temperature below 46°F. The day of the year with the coolest water is February 19, with an average temperature of 39°F.

Average Water Temperature in Incheon

Average Water Temperature in IncheonwarmcoolJanFebMarAprMayJunJulAugSepOctNovDec30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°FAug 2176°FAug 2176°F39°FFeb 1939°FFeb 19Jul 668°FJul 668°FOct 968°FOct 968°FDec 2446°FDec 2446°FApr 1546°FApr 1546°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

To characterize how pleasant the weather is in Incheon throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Incheon for general outdoor tourist activities are from late May to mid July and from mid August to late September, with a peak score in the second week of June.

Tourism Score in Incheon

Tourism Score in Incheonbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.86.80.00.06.86.85.75.7NowNowprecipitationprecipitationcloudscloudstemperaturetemperaturetourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Incheon for hot-weather activities is from mid July to late August, with a peak score in the second week of August.

Beach/Pool Score in Incheon

Beach/Pool Score in Incheonbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.16.10.00.0NowNowprecipitationprecipitationcloudscloudstemperaturetemperature beach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Incheon typically lasts for 7.3 months (224 days), from around March 30 to around November 9, rarely starting before March 15 or after April 14, and rarely ending before October 23 or after November 25.

Time Spent in Various Temperature Bands and the Growing Season in Incheon

Time Spent in Various Temperature Bands and the Growing Season in Incheongrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Mar 3050%Mar 3050%Nov 950%Nov 990%Apr 1490%Apr 1490%Oct 2390%Oct 2310%Mar 1510%Mar 1510%Nov 2510%Nov 250%Jan 300%Jan 30Jul 19100%Jul 19100%NowNowfreezingvery coldcoolcomfortablewarmhotcoldfrigid
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Incheon should appear around April 18, only rarely appearing before April 9 or after April 27.

Growing Degree Days in Incheon

Growing Degree Days in IncheonJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°F3,000°F3,000°F3,500°F3,500°FApr 1888°FApr 1888°FJun 18900°FJun 18900°FJul 251,800°FJul 251,800°FDec 313,683°FDec 313,683°FNowNow
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences significant seasonal variation over the course of the year.

The brighter period of the year lasts for 3.6 months, from April 18 to August 5, with an average daily incident shortwave energy per square meter above 5.7 kWh. The brightest day of the year is June 1, with an average of 6.5 kWh.

The darker period of the year lasts for 2.9 months, from November 6 to February 3, with an average daily incident shortwave energy per square meter below 3.1 kWh. The darkest day of the year is December 20, with an average of 2.3 kWh.

Average Daily Incident Shortwave Solar Energy in Incheon

Average Daily Incident Shortwave Solar Energy in IncheonbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhJun 16.5 kWhJun 16.5 kWhDec 202.3 kWhDec 202.3 kWhApr 185.7 kWhApr 185.7 kWhAug 55.7 kWhAug 55.7 kWhNov 63.1 kWhNov 63.1 kWhFeb 33.1 kWhFeb 33.1 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Incheon are 37.456 deg latitude, 126.705 deg longitude, and 141 ft elevation.

The topography within 2 miles of Incheon contains significant variations in elevation, with a maximum elevation change of 591 feet and an average elevation above sea level of 116 feet. Within 10 miles contains significant variations in elevation (1,289 feet). Within 50 miles contains very significant variations in elevation (4,032 feet).

The area within 2 miles of Incheon is covered by sparse vegetation (41%), bare soil (21%), trees (15%), and artificial surfaces (11%), within 10 miles by water (29%) and sparse vegetation (24%), and within 50 miles by water (36%) and trees (25%).

Data Sources

This report illustrates the typical weather in Incheon, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Incheon.

For each station, the records are corrected for the elevation difference between that station and Incheon according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Incheon is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Incheon and a given station.

The stations contributing to this reconstruction are: Gimpo International Airport (RKSS, 55%, 14 kilometers, northeast); Incheon International Airport (RKSI, 26%, 22 kilometers, west); Suwon Ab (RKSW, 13%, 36 kilometers, southeast); and Mangilsan Ab (RKTM, 6%, 63 kilometers, south).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.