Stuttgart 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 | ~23 Apr 2027 | 13 Apr – 4 May | validated | 2.29 d |
| Forsythia | Season over | ~17 Mar 2027 | 6 Mar – 3 Apr | validated | 4.53 d |
| Wood anemone | Season over | ~23 Mar 2027 | 18 Mar – 30 Mar | approximate | 5.21 d |
| Sweet cherry blossom | Season over | ~10 Apr 2027 | 3 Apr – 21 Apr | validated | 4.35 d |
| Horse chestnut | Season over | ~26 Apr 2027 | 15 Apr – 5 May | validated | 2.57 d |
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Lilac in Stuttgart validated
Season over. Next expected start ~23 Apr 2027. Likely start range (80% of past weather years): 13 Apr 2027 – 4 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): 2.29 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): ±5.93 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:
Forsythia in Stuttgart validated
Season over. Next expected start ~17 Mar 2027. Likely start range (80% of past weather years): 6 Mar 2027 – 3 Apr 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): 4.53 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): ±8.58 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 Stuttgart approximate
Season over. Next expected start ~23 Mar 2027. Likely start range (80% of past weather years): 18 Mar 2027 – 30 Mar 2027. Expected flowering length: ~36 days (measured in Sweden).
Not called validated: backtest error 5.21 days is above our 5-day bar.
- Typical error if the weather were known (model backtest, MAE): 5.21 days; 63% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±6.38 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 Stuttgart validated
Season over. Next expected start ~10 Apr 2027. Likely start range (80% of past weather years): 3 Apr 2027 – 21 Apr 2027. Expected flowering length: ~13 days.
Backtested against 10 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): 4.35 days; 60% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±5.03 days. Months ahead, the weather is unknown, so expect about this much.
- Observations used: 10 years at this city (1992–2013).
Observed first-bloom date by year (city median of observers) vs. model expectation:
Horse chestnut in Stuttgart validated
Season over. Next expected start ~26 Apr 2027. Likely start range (80% of past weather years): 15 Apr 2027 – 5 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): 2.57 days; 91% of years within ±5 days.
- Typical error of a long-range estimate like this one (spread of past years at this city, MAE): ±5.44 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.