Winter Weather in Incheon South Korea

Daily high temperatures are around 38°F, rarely falling below 23°F or exceeding 53°F. The lowest daily average high temperature is 33°F on January 19.

Daily low temperatures are around 24°F, rarely falling below 8°F or exceeding 39°F. The lowest daily average low temperature is 19°F on January 18.

For reference, on August 3, the hottest day of the year, temperatures in Incheon typically range from 73°F to 85°F, while on January 18, the coldest day of the year, they range from 19°F to 33°F.

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

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

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The winter in Incheon experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 34% to 41%.

The clearest day of the winter is December 15, with clear, mostly clear, or partly cloudy conditions 67% of the time.

For reference, on July 13, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on October 19, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 72%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Incheon, the chance of a wet day over the course of the winter is essentially constant, remaining around 12% throughout.

For reference, the year's highest daily chance of a wet day is 52% on July 21, and its lowest chance is 9% on January 23.

Over the course of the winter in Incheon, the chance of a day with only rain remains an essentially constant 9% throughout, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 1% throughout.

Rainfall

To show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during the winter in Incheon is essentially constant, remaining about 0.8 inches throughout, and rarely exceeding 2.3 inches.

The lowest average 31-day accumulation is 0.4 inches on January 16.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day snowfall during the winter in Incheon is essentially constant, remaining about 0.9 inches throughout, and rarely exceeding 4.3 inches or falling below -0.0 inches.

The highest average 31-day accumulation is 1.3 inches on January 23.

Over the course of the winter in Incheon, the length of the day is rapidly increasing. From the start to the end of the season, the length of the day increases by 1 hour, 33 minutes, implying an average daily increase of 1 minute, 3 seconds, and weekly increase of 7 minutes, 20 seconds.

The shortest day of the winter is December 21, with 9 hours, 35 minutes of daylight and the longest day is February 28, with 11 hours, 20 minutes of daylight.

The latest sunrise of the winter in Incheon is 7:48 AM on January 6 and the earliest sunrise is 42 minutes earlier at 7:06 AM on February 28.

The earliest sunset is 5:14 PM on December 6 and the latest sunset is 1 hour, 11 minutes later at 6:25 PM on February 28.

Daylight saving time is not observed in Incheon during 2024.

For reference, on June 20, the longest day of the year, the Sun rises at 5:12 AM and sets 14 hours, 45 minutes later, at 7:57 PM, while on December 21, the shortest day of the year, it rises at 7:44 AM and sets 9 hours, 35 minutes later, at 5:18 PM.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

The figure below presents a compact representation of key lunar data for the winter of 2024. 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. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

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.

The chance that a given day will be muggy in Incheon is essentially constant during the winter, remaining around 0% throughout.

For reference, on August 2, the muggiest day of the year, there are muggy conditions 93% of the time, while on November 8, the least muggy day of the year, there are muggy conditions 0% of the time.

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 is essentially constant during the winter, remaining within 0.2 miles per hour of 10.6 miles per hour throughout.

For reference, on December 24, the windiest day of the year, the daily average wind speed is 10.9 miles per hour, while on June 13, the calmest day of the year, the daily average wind speed is 7.1 miles per hour.

The highest daily average wind speed during the winter is 10.9 miles per hour on December 25.

The wind direction in Incheon during the winter is predominantly out of the north from December 1 to February 25 and the west from February 25 to February 28.

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 surface water temperature in Incheon is very rapidly decreasing during the winter, falling by 13°F, from 52°F to 39°F, over the course of the season.

The lowest average surface water temperature during the winter is 39°F on February 20.

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 29 to around November 8, rarely starting before March 14 or after April 13, and rarely ending before October 22 or after November 24.

The winter in Incheon is reliably fully outside of 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.

The average accumulated growing degree days in Incheon are very rapidly decreasing during the winter, decreasing by 3,679°F, from 3,681°F to 2°F, over the course of the season.

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 in Incheon is rapidly increasing during the winter, rising by 1.6 kWh, from 2.4 kWh to 4.0 kWh, over the course of the season.

The lowest average daily incident shortwave solar energy during the winter is 2.3 kWh on December 19.

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%).