Weather In Jeju In June 2025. In general, the average temperature in jeju city at the beginning of june is 22.9 °c. You can expect warm maximum daytime temperatures of around 23°c and nighttime temperatures around.

If the temperature is a big factor for you to help you decide when to visit, the chart below shows the average minimum and maximum temperatures in jeju for each. Temperature, high temperature, low temperature, precipitation, daily sun hours, sea temperature.