August has the warmest sea of the year, at about 25 °C, and highs of 31 °C — and it is the most crowded month in Split, with Croatians on holiday alongside everyone else. It suits beach-and-boat trips planned around early mornings; anyone with flexible dates should look at September.
By Marin Perić
For the sea, it is the best month of the year. For everything else, it is the hardest. The water is at its warmest, the nights are hot and long, and every boat runs. But the airport is almost as busy as in July — about 758,000 passengers in August 2025 — cruise calls peak, and Croatia itself is on holiday around the two public holidays in the middle of the month. August works if you swim early, rest at midday and accept that nothing is spontaneous.
The DHMZ Split-Marjan normals give an average high of 30.9 °C and a low of 22.9 °C — essentially the same as July. About 20 days in an average August reach 30 °C. Rain is scarce, 32 mm over about three days, though the storms that make September wetter can start in the last week. Sunshine averages almost eleven hours a day, and sunset is back before eight by mid-month.
Yes — this is the warmest sea of the year, averaging about 25 °C, with a ten-year range of roughly 23 °C to 28 °C. The catch is space: Bačvice and the town beaches are full from late morning. Walk west under the Marjan pines, or take a boat to a cove.
Where to find room: Kašjuni, or the full
The number that matters in August is not the high but the low. Nights average 22.9 °C at the Split-Marjan station, so stone streets and old apartments do not cool down after dark. Air conditioning is worth paying for, and a room that faces away from the Riva will be quieter as well as cooler. Drink more water than you think you need, carry a hat for the palace, and leave anything inland — Krka, Klis, Salona — for the first hours of the morning.
5 August — Victory and Homeland Thanksgiving Day, a public holiday.
15 August — Assumption of Mary (Velika Gospa), a public holiday and the heart of the Croatian summer holiday. The fortnight around it is the busiest of the year on the coast.
Cruise calls peak: Split logged 48 cruise visits in August 2025, more than in June, July or September that year. On a ship day the palace is packed from about eleven to four.
The Split Summer Festival continues until mid-August — 14 August in 2026 — with opera on the Peristyle.
Late August brings a festival built around the palace's Roman past, staged on the Peristyle and in the palace. In 2026 it ran from 27 to 30 August under the name Stories of Diocletian.
The festival programme: Split Summer Festival.
Everything, at full timetable, and full. Catamarans to the islands run several times a day and sell out on popular sailings. Krka is at its €40 summer price for adults, and like everything else it is best first thing in the morning.
Swim at seven, palace at eight, coffee in a side street at ten, and stay out of the stone heat from noon to five. The evenings are the reason to come: drinks at Sustipan for sunset, dinner late, and the Riva busy until the small hours. If you are with children, the morning-and-evening rhythm suits them too.
See Sustipan for sunset,
the Riva bars and
things to do in Split with kids.
Everything, as early as you can. Rooms months ahead, and look for air conditioning and a quiet street rather than a view of the Riva. Catamaran tickets several days ahead. Boat trips and restaurant tables well ahead, especially around 15 August.
Budgeting: is Split expensive?
Comparing months? Read Split in summer and
Where these numbers come from: air temperature, rain and sunshine are the 1991–2020 climate normals for the Croatian Meteorological and Hydrological Service (DHMZ) station at Split-Marjan, 122 m up on Marjan hill, as published by the World Meteorological Organization through NOAA. A rain day is one with at least 1 mm. Sea temperature is the ten-year average for Split from seatemperature.info. Daylight and sunset are for the 15th of the month. Passenger figures are from the Croatian Bureau of Statistics.
Get out there
Guided trips that include this stop, with live availability.
Boat trips
A full day on a fast twelve-seat boat: the Blue Cave on Biševo, the Monk Seal cave, Stiniva's famous cove, lunch on Vis and a swim off Budikovac's turquoise lagoon, finishing with a stop at Hvar town. Ten and a half hours, small group, no coach transfer.
History
Ninety minutes through the palace with a guide who lives inside it: the Golden Gate, the cellars, the Peristyle, the cathedral and the streets in between. Small group, no flag, and a proper explanation of why a Roman emperor retired to a cabbage patch in Dalmatia.
Boat trips
Five hours to Šolta and back on a ten-person boat: three swim stops in coves you cannot reach by road, an hour in Maslinica for dinner or a drink, and the run home across the channel as the sun goes down behind the island.