Month-specific sea-surface temperature · Greece

Santorini Sea Temperature in April

17.8°C

64.0°F

In April, sea-surface temperature near Santorini has a historical monthly average of 17.8°C. This is not the reading for any particular holiday date.

Across 2022–2025, the lowest and highest yearly April monthly means were 17.3–18.4°C. These are not daily extremes.

Previous month

March · 17.1°C

Change into April: +0.7°C

Next month

May · 19.3°C

Change into next month: +1.5°C

Can you swim or snorkel in Santorini in April?

At 17.8°C our temperature-only guide describes the water as cold water. Comfort depends on your cold tolerance, immersion time and wind. A historical average cannot determine whether conditions are safe on any given day.

Do you need a wetsuit?

Use a full 3-5 mm wetsuit and keep the session within your cold-water experience.

Which beach should you choose?

Look for a beach sheltered from the actual forecast waves and wind on your visit. Exposure, currents and entry conditions vary even where water temperatures are similar. Follow local warnings.

Check the current waves, wind and snorkeling forecast →

A live forecast does not predict a future April. Check again close to your trip.

Santorini Sea Temperature: All 12 Months

Choose a month for available historical evidence, month comparisons and swim guidance. Missing history is clearly marked and never presented as a long-term normal.

January 17.9°C February 17.2°C March 17.1°C April 17.8°C May 19.3°C June 22.7°C July 24.6°C August 25.9°C September 25.1°C October 23.1°C November 21.3°C December 19.0°C

Data source and limitations

Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature; 2022–2025. Marine model grid near 36.39, 25.46. Based on 3 yearly monthly means and 2160 recorded samples. Source methodology.

Modelled sea-surface temperatures do not establish underwater visibility, wildlife, calm currents or safe entry.