Average Weather in Jeju City South Korea
In Jeju City, the temperature typically varies from 37°F to 85°F over the course of the year, and is rarely below 31°F or above 91°F.
The hot season lasts for 2.8 months, from June 24 to September 17, with an average daily high temperature above 77°F. The hottest day of the year is August 3, with an average high of 85°F and low of 76°F.
The cool season lasts for 3.3 months, from December 5 to March 15, with an average daily high temperature below 53°F. The coldest day of the year is January 28, with an average low of 37°F and high of 45°F.
Average High and Low Temperature
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
The length of the day in Jeju City varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 56 minutes of daylight; the longest day is June 21, with 14 hours, 23 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:23 AM on June 12, and the latest sunrise is 2 hours, 15 minutes later at 7:38 AM on January 8. The earliest sunset is at 5:25 PM on December 4, and the latest sunset is 2 hours, 22 minutes later at 7:47 PM on June 30.
Daylight saving time (DST) is not observed in Jeju City during 2017.
Sunrise & Sunset with Twilight
In Jeju City, 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 Jeju City begins around September 5 and lasts for 6.5 months, ending around March 19. On December 14, 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 19 and lasts for 5.5 months, ending around September 5. On July 2, the cloudiest day of the year, the sky is overcast or mostly cloudy 69% of the time, and clear, mostly clear, or partly cloudy 31% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Jeju City varies significantly throughout the year.
The wetter season lasts 3.0 months, from June 9 to September 10, with a greater than 33% chance of a given day being a wet day. The chance of a wet day peaks at 53% on July 5.
The drier season lasts 9.0 months, from September 10 to June 9. The smallest chance of a wet day is 13% on December 21.
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 53% on July 5.
Daily Chance of Precipitation
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 in the year. Jeju City experiences very significant seasonal variation in monthly rainfall.
Rain falls throughout the year in Jeju City. The most rain falls during the 31 days centered around July 3, with an average total accumulation of 10.5 inches.
The least rain falls around December 29, with and average total accumulation of 1.3 inches.
Average Monthly Rainfall
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.
Jeju City experiences very significant seasonal variation in the perceived humidity.
The muggier period of the year lasts for 3.8 months, from June 7 to October 2, during which time the comfort level is muggy, oppressive, or miserable at least 25% of the time. The muggiest day of the year is August 3, with muggy conditions 99% of the time.
The least muggy day of the year is January 20, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
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 Jeju City experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 5.4 months, from October 25 to April 8, with average wind speeds of more than 7.3 miles per hour. The windiest day of the year is January 18, with an average hourly wind speed of 9.4 miles per hour.
The calmer time of year lasts for 6.5 months, from April 8 to October 25. The calmest day of the year is June 6, with an average hourly wind speed of 5.3 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Jeju City varies throughout the year.
The wind is most often from the south for 2.1 weeks, from April 30 to May 15 and for 1.8 months, from June 22 to August 15, with a peak percentage of 52% on July 17. The wind is most often from the north for 6.0 days, from May 15 to May 21 and for 7.9 months, from September 3 to April 30, with a peak percentage of 72% on January 21. The wind is most often from the east for 1.0 months, from May 21 to June 22 and for 2.7 weeks, from August 15 to September 3, with a peak percentage of 38% on September 15.
Jeju City 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 2.3 months, from July 16 to September 25, with an average temperature above 75°F. The day of the year with the warmest water is August 15, with an average temperature of 80°F.
The time of year with cooler water lasts for 4.6 months, from December 27 to May 14, with an average temperature below 61°F. The day of the year with the coolest water is March 10, with an average temperature of 56°F.
Average Water Temperature
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 2.6 months, from April 13 to June 30, with an average daily incident shortwave energy per square meter above 5.6 kWh. The brightest day of the year is May 22, with an average of 6.4 kWh.
The darker period of the year lasts for 2.8 months, from November 11 to February 6, with an average daily incident shortwave energy per square meter below 3.4 kWh. The darkest day of the year is December 27, with an average of 2.6 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Jeju City are 33.510 deg latitude, 126.522 deg longitude, and 108 ft elevation (map ).
The topography within 2 miles of Jeju City contains only modest variations in elevation, with a maximum elevation change of 456 feet, and an average elevation above sea level of 136 feet. Within 10 miles contains extreme variations in elevation (5,889 feet). Within 50 miles also contains extreme variations in elevation (6,339 feet).
The area within 2 miles of Jeju City is covered by water (47%), trees (17%), grassland (14%), and cropland (13%), within 10 miles by water (59%) and trees (27%), and within 50 miles by water (94%).
This report illustrates the typical weather in Jeju City, 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 is only a single weather station, Jeju International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Jeju City.
At a distance of 3 kilometers from Jeju City, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.
The station records are corrected for the elevation difference between the station and Jeju City according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports and weather stations are provided by AskGeo.com .