Hamburg Germany
Expected first-bloom dates for spring 2027, based on a degree-day temperature model and years of observations. 25 Apr 2027 status shown.
| Flower | Status today | Expected start | Likely range | Reliability | Model error (backtest) |
|---|---|---|---|---|---|
| Lilac | Soon | ~6 May 2027 | 24 Apr – 15 May | validated | 3.13 d |
| Forsythia | Season over | ~23 Mar 2028 | 9 Mar – 12 Apr | validated | 4.36 d |
| Wood anemone | Blooming | ~27 Mar 2027 | 20 Mar – 8 Apr | validated | 3.94 d |
| Sweet cherry blossom | Blooming | ~16 Apr 2027 | 9 Apr – 24 Apr | validated | 3.14 d |
| Horse chestnut | Soon | ~6 May 2027 | 24 Apr – 11 May | validated | 3.66 d |
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Lilac in Hamburg validated
Expected to start in ~11 days (~6 May 2027). Likely start range (80% of past weather years): 24 Apr 2027 – 15 May 2027. Expected flowering length: ~20 days (measured in Sweden).
Backtested against 35 years of local observations at this city (leave-one-year-out); the model beat simple climatology.
- Typical error if the weather were known (model backtest, MAE): 3.13 days; 83% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±6.31 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 35 years at this city (1991–2025).
Observed first-bloom date by year (city median of observers) vs. model expectation:
Forsythia in Hamburg validated
Season over. Next expected start ~23 Mar 2028. Likely start range (80% of past weather years): 9 Mar 2028 – 12 Apr 2028. Expected flowering length: ~14 days (assumed, not measured).
Backtested against 35 years of local observations at this city (leave-one-year-out); the model beat simple climatology.
- Typical error if the weather were known (model backtest, MAE): 4.36 days; 69% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±10.93 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 35 years at this city (1991–2025).
Observed first-bloom date by year (city median of observers) vs. model expectation:
Wood anemone in Hamburg validated
Expected in bloom now (started ~27 Mar, ends ~2 May). Likely start range (80% of past weather years): 20 Mar 2027 – 8 Apr 2027. Expected flowering length: ~36 days (measured in Sweden).
Backtested against 35 years of local observations at this city (leave-one-year-out); the model beat simple climatology.
- Typical error if the weather were known (model backtest, MAE): 3.94 days; 71% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±6.81 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 35 years at this city (1991–2025).
Observed first-bloom date by year (city median of observers) vs. model expectation:
Sweet cherry blossom in Hamburg validated
Expected in bloom now (started ~16 Apr, ends ~29 Apr). Likely start range (80% of past weather years): 9 Apr 2027 – 24 Apr 2027. Expected flowering length: ~13 days.
Backtested against 21 years of local observations at this city (leave-one-year-out); the model beat simple climatology.
- Typical error if the weather were known (model backtest, MAE): 3.14 days; 81% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±5.3 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 21 years at this city (1991–2014).
Observed first-bloom date by year (city median of observers) vs. model expectation:
Horse chestnut in Hamburg validated
Expected to start in ~11 days (~6 May 2027). Likely start range (80% of past weather years): 24 Apr 2027 – 11 May 2027. Expected flowering length: ~14 days (assumed, not measured).
Backtested against 35 years of local observations at this city (leave-one-year-out); the model beat simple climatology.
- Typical error if the weather were known (model backtest, MAE): 3.66 days; 77% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±6.06 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 35 years at this city (1991–2025).
Observed first-bloom date by year (city median of observers) vs. model expectation:
“Start” = first flowers open (BBCH 60), not the peak. Peak is usually later; we have no open peak data. Individual gardens differ by ±4–8 days from the city median. See How it works and Sources.