The Seoul Metropolitan Government issued an ozone advisory for all 25 districts in the city on Friday.

The ozone level in some areas surpassed an average of zero-point-12 parts per million within a period of one hour, the point at which city officials issue an advisory.

The city government has advised people in the affected regions to avoid driving and outdoor activities. 

Amid hotter-than-usual temperatures, the Korea Meteorological Administration also issued heat wave advisories for most parts of the country, including the first advisory of the year for Seoul. 

The weather agency said daytime highs in the capital city will continue to exceed 30 degrees Celsius this weekend.

Temperatures are projected to cool down to seasonal norms when rain drenches the nation on Monday.