Frankfurt Germany
Expected first-bloom dates for spring 2027, based on a degree-day temperature model and years of observations. 16 Oct 2026 status shown.
| Flower | Status today | Expected start | Likely range | Reliability | Model error (backtest) |
|---|---|---|---|---|---|
| Lilac | Season over | ~22 Apr 2027 | 13 Apr – 5 May | validated | 3.7 d |
| Forsythia | Season over | ~17 Mar 2027 | 5 Mar – 3 Apr | approximate | 5.39 d |
| Wood anemone | Season over | ~23 Mar 2027 | 18 Mar – 29 Mar | validated | 3.26 d |
| Sweet cherry blossom | Season over | ~10 Apr 2027 | 3 Apr – 18 Apr | validated | 4.23 d |
| Horse chestnut | Season over | ~24 Apr 2027 | 15 Apr – 6 May | validated | 2.94 d |
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Lilac in Frankfurt validated
Season over. Next expected start ~22 Apr 2027. Likely start range (80% of past weather years): 13 Apr 2027 – 5 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): 3.7 days; 74% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±6.33 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 Frankfurt approximate
Season over. Next expected start ~17 Mar 2027. Likely start range (80% of past weather years): 5 Mar 2027 – 3 Apr 2027. Expected flowering length: ~14 days (assumed, not measured).
Not called validated: backtest error 5.39 days is above our 5-day bar.
- Typical error if the weather were known (model backtest, MAE): 5.39 days; 66% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±8.71 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 Frankfurt validated
Season over. Next expected start ~23 Mar 2027. Likely start range (80% of past weather years): 18 Mar 2027 – 29 Mar 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): 3.26 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): ±5.55 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 Frankfurt validated
Season over. Next expected start ~10 Apr 2027. Likely start range (80% of past weather years): 3 Apr 2027 – 18 Apr 2027. Expected flowering length: ~13 days.
Backtested against 11 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): 4.23 days; 73% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±5.36 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 11 years at this city (1991–2013).
Observed first-bloom date by year (city median of observers) vs. model expectation:
Horse chestnut in Frankfurt validated
Season over. Next expected start ~24 Apr 2027. Likely start range (80% of past weather years): 15 Apr 2027 – 6 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): 2.94 days; 86% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±5.11 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.