Neerslag — 2020
| Month | Katwijk | Wassenaar | Difference |
|---|---|---|---|
| Jan | 69.1 mm | 82.7 mm | -13.6 |
| Feb | 126.9 mm | 136.9 mm | -10.0 |
| Mar | 45.3 mm | 46.1 mm | -0.8 |
| Apr | 25.5 mm | 26 mm | -0.5 |
| May | 16.9 mm | 19.7 mm | -2.8 |
| Jun | 64.4 mm | 66 mm | -1.6 |
| Jul | 71.2 mm | 80.5 mm | -9.3 |
| Aug |
| – |
| – |
| – |
| Sep | – | – | – |
| Oct | – | – | – |
| Nov | – | – | – |
| Dec | – | – | – |