The perception that the sea feels warmer at night is often attributed to several factors:
Air temperature: During the day, the sun's rays warm both the air and the sea. However, after sunset, the air temperature tends to cool down more quickly than the water temperature. As a result, the relatively cooler air at night can create the sensation of the sea being warmer in comparison.
Thermal inertia: Water has a higher specific heat capacity than air, meaning it can retain heat for longer periods. As a result, even after the sun sets, the sea retains some of the heat it absorbed during the day. This thermal inertia can make the water feel relatively warmer compared to the surrounding air at night.
Human perception: Our perception of temperature can be influenced by various factors, including our expectations and the immediate environment. At night, the air temperature tends to be cooler, and our bodies adjust to that cooler temperature. When we enter the sea, which is still relatively warmer, it can give us the sensation of the water being warmer than it actually is.
It's important to note that these factors may vary depending on the specific location and weather conditions. The perception of the sea feeling warmer at night can also be subjective and vary from person to person.