Bewolking — 2020
| Month | Zwijndrecht | Alblasserdam | Difference |
|---|---|---|---|
| Jan | 76.4 % | 78.6 % | -2.2 |
| Feb | 75.2 % | 74.8 % | +0.4 |
| Mar | 52.2 % | 53 % | -0.8 |
| Apr | 33.7 % | 36.1 % | -2.4 |
| May | 47.6 % | 47.8 % | -0.2 |
| Jun | 64 % | 65.3 % | -1.3 |
| Jul | 61.9 % | 63 % | -1.1 |
| Aug |
| – |
| – |
| – |
| Sep | – | – | – |
| Oct | – | – | – |
| Nov | – | – | – |
| Dec | – | – | – |