Is the sea cool?
To the question “Is the sea cool?” there is no single answer, because seawater temperature varies a lot depending on location, season and depth. On the coast of Finland and in the archipelago, the sea is generally cooler than, for example, in the Mediterranean, and even in summer it often stays quite cool compared to a heated swimming pool.
Factors affecting seawater temperature
Seawater temperature is affected by several factors:
- Geographic location: sea areas closer to the equator are usually warmer than sea areas near the poles.
- Season: in summer the sea is usually warmer than in winter, because the sun heats the water more.
- Depth: surface water is usually warmer than deeper water, since sunlight cannot heat the deeper layers as effectively.
- Ocean currents: currents can carry warmer or colder water into an area and change the local temperature.
Sea temperature in different parts of the world
As a rough guide:
- Baltic Sea (including the Finnish coast): typically cold, close to freezing in winter and roughly 15–20 °C at the surface in summer.
- Mediterranean Sea: noticeably warmer than the Baltic, often around 25–30 °C in summer and 10–15 °C in winter.
- Pacific Ocean: varies greatly by region – over 25 °C near the equator, much colder near the poles.
These are typical ranges rather than exact figures, since actual temperatures shift from year to year and place to place.
Conclusion
Seawater temperature depends on location, season, depth and currents, so there is no single answer to whether the sea is cold or cool – it depends on where and when you ask. For up-to-date figures for a specific area, check local weather or marine weather services.
Source: Finnish Meteorological Institute
NOAA: Oceans & Coasts
