Temperatuur — 2020
| Month | Katwijk | Voorschoten | Difference |
|---|---|---|---|
| Jan | 6.8 °C | 6.5 °C | +0.3 |
| Feb | 7.3 °C | 7.3 °C | +0.0 |
| Mar | 6.9 °C | 6.9 °C | +0.0 |
| Apr | 10.2 °C | 10.8 °C | -0.6 |
| May | 12.5 °C | 13.1 °C | -0.6 |
| Jun | 16.5 °C | 17.1 °C | -0.6 |
| Jul | 16.9 °C | 17.1 °C | -0.2 |
| Aug |
| – |
| – |
| – |
| Sep | – | – | – |
| Oct | – | – | – |
| Nov | – | – | – |
| Dec | – | – | – |