You can’t rely on great weather at any time of the year, but in the summer months we do tend to get days that are warm and sunny. Unfortunately, it can become stiflingly hot inland, with little respite from that heat.
There are several reasons why people head for the coast on warm sunny days. If you like to swim in the sea, there is no better time to do it than on days like these. However, it can also be cooler on the coast than it is inland. The air over the sea will generally be colder than that over the land, because land warms up far faster than water. So, if you want some of that fresh cool air, the coast is the place to head for.
However, it does depend on the wind direction. To benefit from cooler air temperatures, the wind must be blowing in from the sea. If it is blowing out towards the sea, it will merely bring the heat from inland towards the coast. That means there will be little to no respite from the heat felt by others inland.
You should also consider the issue of sunshine. Anywhere will feel warmer in the sun than it will in the shade. The coastal areas generally do get more sunshine too, because we have more stable air over water than we do over land. That means there is less chance that clouds will build up there. You could be inland and witness nothing but cloudy weather, and yet the coast will deliver nothing but sunshine. So, don’t be surprised if the weather on the coast is better than it is inland at times. It is a balance of temperature versus sunshine, and most people would probably rather it be slightly cooler and sunnier than the other way around.
It is important not to get caught out, though, because even when it is cooler, you’ll still be soaking up more sun than you would inland. That means you should take care to cover up and wear sunscreen, and not to simply judge what the weather is like from the temperature you feel.
Finally, don’t be fooled if you arrive at the coast early only to find fog or cloud hanging over the area. It soon disappears when the day warms up, as it will head back out to sea. The weather systems around coastal areas are therefore quite predictable in many cases. If you aren’t used to them, you now know how to benefit from enjoying a day or two at the seaside if the weather is good. Even if it doesn’t feel quite as warm, it is usually more appealing and enjoyable than it would be further inland, where it can be quite stifling.