Bewolking — 2026
| Month | Heemskerk | Velsen | Difference |
|---|---|---|---|
| Jan | – | – | – |
| Feb | – | – | – |
| Mar | 53.4 % | 53.4 % | +0.0 |
| Apr | 79.4 % | 81.2 % | -1.8 |
| May | 57.7 % | 56.2 % | +1.5 |
| Jun | 59.8 % | 58.1 % | +1.7 |
| Jul | 51.9 % | 50.5 % | +1.4 |
| Aug |
| 51.5 % |
| 49.8 % |
| +1.7 |
| Sep | 70.1 % | 70 % | +0.1 |
| Oct | 66.5 % | 65.7 % | +0.8 |
| Nov | – | – | – |
| Dec | – | – | – |