Colder than forecast
On Thursday 15 October in Boiro, a high of 22.5 °C was expected and it only got to 17.2 °C
Humidity stayed at 95% or more for 7 hours in the middle of the day, as usual with fog or low cloud.
Boiro station (AEMET), 1 km from Boiro.
What happened
- Only the ECMWF AIFS saw it coming: it gave 19 °C.
- Humidity stayed at 95% or more for 7 hours in the middle of the day, as usual with fog or low cloud.
- The Atlas Forecast missed too: 2.8 °C average error each hour (the median of the models, 3 °C).
What each model gave
| Model | For that day (0–24 h) | A day earlier (24–48 h) |
|---|---|---|
| ECMWF IFS | 20.8 °C | 20.6 °C |
| ECMWF AIFS (saw it) | 19 °C | 19.3 °C |
| GFS | 23.1 °C | 23.4 °C |
| ICON | 22.4 °C | 22.7 °C |
| ARPEGE | 22.7 °C | 22.2 °C |
| UKMO | 25.3 °C | 24.3 °C |
| Median | 22.5 °C | 22.5 °C |
| Measured | 17.2 °C | |
Hour by hour
Temperature at the Boiro station, with each model's forecast for that same day (0–24 h). Spanish mainland time.
- Measured
- Median of the models
- ECMWF AIFS (saw it)
- Each of the other models
Show the data in a table
| Time | Measured | ECMWF IFS | ECMWF AIFS | GFS | ICON | ARPEGE | UKMO |
|---|---|---|---|---|---|---|---|
| 03:00 | 12.1 | 14.3 | 14.8 | 14.9 | 16.7 | 14.1 | 14.1 |
| 04:00 | 11.8 | 14.2 | 14.4 | 14.8 | 16.8 | 14.3 | 13.9 |
| 05:00 | 11.1 | 14.1 | 14.1 | 14.5 | 16 | 14.5 | 13.4 |
| 06:00 | 10.8 | 14 | 13.9 | 14.3 | 15.8 | 14.6 | 13.1 |
| 07:00 | 11.4 | 13.8 | 13.8 | 14.1 | 15.5 | 14.8 | 12.6 |
| 08:00 | 11.9 | 13.8 | 14 | 13.7 | 14.8 | 14.7 | 11.8 |
| 09:00 | 12.3 | 13.8 | 14.6 | 13.4 | 14.9 | 14.4 | 12.1 |
| 10:00 | 13.4 | 13.9 | 15.5 | 15.6 | 15.5 | 14.3 | 13.7 |
| 11:00 | 14.3 | 14.5 | 16.6 | 19.2 | 17.4 | 14.6 | 16 |
| 12:00 | 14.9 | 16.2 | 17.6 | 21.8 | 19.2 | 16.4 | 19.1 |
| 13:00 | 15.3 | 18.5 | 18.5 | 22.8 | 19.9 | 17.7 | 21.6 |
| 14:00 | 15.9 | 20.1 | 19 | 23.1 | 20.8 | 18.8 | 23.5 |
| 15:00 | 16.5 | 20.8 | 19 | 22.5 | 21.5 | 18.6 | 24.7 |
| 16:00 | 16.8 | 20.8 | 18.8 | 21.9 | 22.1 | 21.2 | 25.3 |
| 17:00 | 16.5 | 20.4 | 18.4 | 20.9 | 22.4 | 20.5 | 25.3 |
| 18:00 | 16.8 | 19.5 | 17.9 | 19.7 | 21.7 | 21.5 | 24.7 |
| 19:00 | 17.2 | 18.1 | 17.4 | 18 | 20.4 | 22.7 | 23.2 |
| 20:00 | 16.4 | 17 | 16.9 | 15.2 | 18.5 | 20.2 | 19.7 |
| 21:00 | 14.9 | 16.3 | 16.5 | 15.1 | 17.3 | 18.2 | 18.1 |
| 22:00 | 13.6 | 15.8 | 16.1 | 15.2 | 15.8 | 17.3 | 16.9 |
| 23:00 | 12.7 | 15.5 | 15.7 | 15 | 14.9 | 16.4 | 15.8 |
| 00:00 | 12.2 | 15.3 | 15.3 | 14.7 | 14.8 | 15.5 | 15 |
| 01:00 | 11.7 | 15.3 | 14.9 | 14.4 | 14.7 | 15.4 | 14.2 |
| 02:00 | 11.6 | 15.1 | 14.5 | 14 | 14.4 | 15.2 | 13.6 |
Weather in Boiro · Model accuracy · The model league · Other misses
How we spot them
Every day we compare what the Meteocat (in Catalonia) and AEMET weather stations measured the day before with what each model had forecast for that same day (0–24 h ahead). It counts as a notable miss if 15 mm or more fell and the median of the models gave less than 3; if it gave 15 mm or more and less than 1 fell; if the high was off by 4 °C or more (and by at least 4 °C more than that station usually is); or if a gust went over 60 km/h and was 25 km/h or more above the forecast. Stations within 40 km with the same miss count as one episode, and we show at most 5 per day.
The explanations come from the same data: which model saw it, whether the rain came earlier or later, whether it fell (or was forecast) a few kilometres away, whether it was very concentrated… When none of that fits, we say so. Days run from midnight to midnight UTC (2 am to 2 am in summer and 1 am to 1 am in winter, Spanish mainland time).
Missing now and then is unavoidable: the weather is chaotic and every model has its days. How often each one gets it right, on average, is in Accuracy and in the model league.