Cheju climate by month
Averages and records for each calendar month at Cheju, South Korea, from 1973 to 2026. The warmest month is August, averaging 30.0°C; the coolest is January at 8.5°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 8.5°C | 3.8°C | 21.5°C6 January 1989 | −10.5°C19 January 1984 | 40 / 54 |
| February | 9.2°C | 4.0°C | 24.5°C21 February 2004 | −6.0°C16 February 1977 | 35 / 54 |
| March | 12.7°C | 7.9°C | 28.3°C25 March 2025 | −6.5°C22 March 2004 | 43 / 54 |
| April | 17.6°C | 12.4°C | 30.1°C28 April 2005 | 0.8°C1 April 1985 | 43 / 54 |
| May | 21.7°C | 15.8°C | 31.6°C13 May 1993 | 6.0°C5 May 1973 | 47 / 54 |
| June | 24.9°C | 20.8°C | 34.5°C30 June 1994 | 6.6°C4 June 1993 | 44 / 54 |
| July | 29.2°C | 24.3°C | 42.7°C8 July 1990 | 13.7°C24 July 1984 | 44 / 54 |
| August | 30.0°C | 26.8°C | 43.4°C8 August 1986 | 14.4°C31 August 2002 | 47 / 54 |
| September | 25.9°C | 24.6°C | 34.6°C7 September 2025 | 8.6°C17 September 2006 | 43 / 54 |
| October | 21.5°C | 20.0°C | 30.8°C13 October 2025 | 1.3°C23 October 1993 | 44 / 53 |
| November | 16.0°C | 11.9°C | 28.4°C1 November 2023 | −3.0°C21 November 2004 | 39 / 53 |
| December | 11.0°C | 6.3°C | 22.2°C28 December 1987 | −6.2°C27 December 1988 | 38 / 53 |
Years shows the number behind the average high, then the number holding a record for that month. They differ because a year contributes an average only when the month has at least 25 days of readings, while a single reading is enough to set a record. The average low is withheld on the same 25-day rule and is counted separately again; it is shown as a dash where the archive cannot support it. Across the twelve months here the averages rest on 35 to 47 years each.
See what Cheju is doing right now
Every figure on this page is computed from NOAA GHCN-Daily observations stored per station, per year, per month. Nothing is modelled, interpolated or estimated, and a month the archive never covered is left out rather than filled in. A station appears here only once all twelve months carry an average from at least 10 years. See how this is built.