The title will be ceremonially handed to Pärnu Mayor Toomas Kivimägi by Deputy Mayor of Tallinn Eha Võrk and Tallinn City Secretary Toomas Sepp at the Vallikäär park in Pärnu at 19:00.
The seaside town Pärnu with a population of around 44,000 people, was first named the summer capital in 1996.
Representatives of the spring, autumn and winter capitals - Türi, Narva and Otepää, respectively - will also be present at the ceremony.
The presentation ceremony will be followed by a concert and the traditional light ceremony.
Another event marking the beginning of summer in Pärnu, the annual Watergate music and culture festival, also starts today.