Bewolking — 2020
| Month | Beverwijk | Heemskerk | Difference |
|---|---|---|---|
| Jan | 79.5 % | 79.5 % | +0.0 |
| Feb | 73.8 % | 73.8 % | +0.0 |
| Mar | 52.2 % | 52.2 % | +0.0 |
| Apr | 40 % | 40 % | +0.0 |
| May | 44.8 % | 44.8 % | +0.0 |
| Jun | 66.1 % | 66.1 % | +0.0 |
| Jul | 61.8 % | 61.8 % | +0.0 |
| Aug |
| – |
| – |
| – |
| Sep | – | – | – |
| Oct | – | – | – |
| Nov | – | – | – |
| Dec | – | – | – |