Summer at the Belgian seaside

We had been promised fabulous weather and tropical temperatures for the weekend, so I went to visit my family at the seaside. Once again the weather forecast had been a bit misleading, because this was what we got:

A lot of wind and not a lot of sun. During one of the sunny spells we ventured out to the beach and had to flee within 10 min because it started raining. And then friends call from Portugal telling they're enjoying the sun on the beach with live Brazilian music and caipirinhas.... I'll have to go back there soon.
What can you do with this weather at the seaside?
You can get an ice cream at De la Poste in Knokke (the best) and you can look for fossils.
Here's my cousin's collection of shark and ray teeth: