Weather statistics, phenology and records
Monthly averages, climate normals, phenology, growing degree days and weather records for Heerhugowaard.
Highest temperature
37.0 C
26 Jun
Lowest temperature
-5.0 C
11 Jan
Total precipitation
547.6 mm
135 Rain days
Strongest wind gust
61.0 km/h
24 Mar
Monthly averages
| Month | Avg temp | Max temp | Min temp | Precipitation | Rain days |
|---|---|---|---|---|---|
| Jan | 2.3 C | 11.0 C | -5.0 C | 93.5 mm | 22 |
| Feb | 4.8 C | 18.0 C | -3.0 C | 39.1 mm | 17 |
| Mar | 8.1 C | 18.0 C | 0.0 C | 57.7 mm | 14 |
| Apr | 10.6 C | 22.0 C | 2.0 C | 6.9 mm | 8 |
| May | 14.5 C | 30.0 C | 5.0 C | 40.4 mm | 13 |
| Jun | 18.8 C | 37.0 C | 9.0 C | 71.4 mm | 14 |
| Jul | 19.5 C | 32.0 C | 14.0 C | 8.6 mm | 6 |
| Aug | 19.3 C | 34.0 C | 11.0 C | 96.0 mm | 15 |
| Sep | 17.2 C | 26.0 C | 10.0 C | 77.2 mm | 18 |
| Oct | 14.9 C | 22.0 C | 7.0 C | 56.9 mm | 8 |
| Nov | -- | -- | -- | -- | -- |
| Dec | -- | -- | -- | -- | -- |
Season Tracker 2026
Seasonal milestones
| Milestone | 2026 | Difference |
|---|---|---|
| 🌸 First spring day | 25 Feb | 237 days earlier |
| ☀️ First summer day | 22 May | — |
| 🌡️ First tropical day | 26 May | — |
| ❄️ Last spring frost | 15 Feb | — |
| 🍂 First autumn frost | — | — |
| 🧊 First ice day | 10 Jan | — |
Growing Degree Days (base 10 °C) — Total GDD: 1353
Peak GDD period
Shows daily GDD bars and a 14-day rolling total so warm stretches stand out.
Best 14-day period
17 Jun
– 30 Jun
178.0 GDD
Average per day: 12.7 GDD
What are Growing Degree Days?
Growing Degree Days (GDD) measure accumulated heat above a base temperature — not calendar days.
Each day contributes a value equal to how many degrees the average temperature exceeds 10 °C. A day with a high of 26 °C and a low of 12 °C contributes (26 + 12) / 2 − 10 = 9 GDD.
The total GDD for a year is the sum of all daily values. A warm summer can easily produce 1 000 – 1 500 GDD, which is why the total is much larger than 365.
Base temperature: 10 °C (growing threshold for most plants in temperate climates).
All-time records
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