We have the most wonderful weather here with temperatures up to 30 degrees C (86F). At the IJssel-lake was a competition between sailboats.
The brave ones took a swim in the, in my opinion, still cold lake.
At the horizon you can see the fortress island Pampus which I visited a few weeks ago at a cold rainy day (look here). You never know what weather it will be here when you have made plans before.