Which weather model is most accurate in Salt Lake City?
Salt Lake City, Utah · daily high temperature · trailing 30 days · refreshed at most every 6 hours
Every day, The Spread archives what each major weather model predicted for Salt Lake City at 1-, 3-, and 7-day leads, then scores those forecasts against ERA5 reanalysis once the day has happened. This page covers the trailing 30 days (2026-07-06 to 2026-08-05), for daily high temperature.
One day out, ECMWF IFS has been most accurate (typical miss 1.47°F); at three days, ECMWF IFS (2.11°F); at seven days, NOAA AIGFS (AI) (4.33°F).
The largest standing bias belongs to ECMWF AIFS (AI), which has run cool by about 3.18°F at 3-day lead over this window.
The Spread's own bias-corrected blend scored a 1.18°F typical miss at one day. Its corrections come from the same window it is scored on (in-sample), so read it as a ceiling, not a promise.
The scoreboard
Typical miss (MAE) with the signed bias in parentheses — positive bias means the model ran warm. Days = scored days behind the 1-day number.
| Model | 1-day | 3-day | 7-day | Days |
|---|---|---|---|---|
| ECMWF IFS | 1.5° (-0.8°) | 2.1° (+0.8°) | 5.4° (+1.4°) | 30 |
| NOAA GFS | 2.0° (+1.6°) | 2.5° (+1.8°) | 4.5° (+3.7°) | 30 |
| DWD ICON | 2.2° (-1.5°) | 2.8° (-1.4°) | — | 30 |
| UKMO (UK) | 2.3° (-1.8°) | 2.4° (-0.2°) | — | 30 |
| GEM (Canada) | 2.4° (-0.8°) | 3.5° (-3.0°) | 4.4° (-2.7°) | 30 |
| ECMWF AIFS (AI) | 2.8° (-2.8°) | 3.4° (-3.2°) | 4.4° (-3.4°) | 30 |
| NOAA AIGFS (AI) | 3.3° (-3.2°) | 2.5° (-1.9°) | 4.3° (-1.8°) | 30 |
| NBM (US blend) | 1.7° (-1.1°) | 2.4° (-0.6°) | 3.7° (-1.4°) | 30 |
| Blended (bias-corrected) | 1.2° (+0.0°) | 1.7° (+0.0°) | 3.3° (-0.0°) | 30 |
Method, honestly
Forecasts come from each model's actual archived runs via Open-Meteo's Previous Runs API — what the model said at the time, not a reconstruction. Truth is ERA5 reanalysis daily highs. Rankings cover the models themselves; the two consensus products at the bottom of the table — NBM, which is itself a blend of models, and The Spread's own bias-corrected blend — are shown for comparison, never ranked or named "most accurate" here. The blend's corrections come from the same trailing window it is scored on (in-sample), so treat its score as a ceiling. A rolling 30-day window means these numbers move — that is the point.
Receipts — was the forecast right?
One page per settled date: what every model said as the day approached, what happened, and who was closest.
- Mon Aug 3 14 days out the models said 90–105; it hit 91. GFS led (off 0.6°); ICON ran 3° cold.
- Sun Aug 2 14 days out the models said 99–101; it hit 101. GFS led (off 0.3°); ICON ran 4° cold.
- Sat Aug 1 14 days out the models said 92–99; it hit 105. ECMWF led (off 0.6°); GEM ran 4° cold.
- Fri Jul 31 14 days out the models said 94–108; it hit 102. ECMWF led (off 0.1°); GEM ran 4° cold.
- Thu Jul 30 13 days out the models said 93–108; it hit 95. GEM led (off 0.1°); GFS ran 4° hot.
- Wed Jul 29 12 days out the models said 94–107; it hit 93. UKMO led (off 0.1°); AIFS ran 7° cold.
- Tue Jul 28 11 days out the models said 88–103; it hit 95. UKMO led (off 0.6°); AIFS ran 2° cold.
- Mon Jul 27 10 days out the models said 92–102; it hit 96. UKMO led (off 0.1°); AIFS ran 4° cold.
- Sun Jul 26 9 days out the models said 85–101; it hit 101. GEM led (off 0.2°); GFS ran 3° hot.
- Sat Jul 25 8 days out the models said 81–102; it hit 102. GEM led (off 0.6°); UKMO ran 4° cold.
- Fri Jul 24 7 days out the models said 82–103; it hit 99. ECMWF led (off 0.0°); AIFS ran 3° cold.
- Thu Jul 23 6 days out the models said 78–96; it hit 96. GFS led (off 0.2°); UKMO ran 5° cold.
- Wed Jul 22 5 days out the models said 80–98; it hit 87. ECMWF led (off 0.2°); AIFS ran 5° cold.
- Tue Jul 21 4 days out the models said 89–98; it hit 99. GFS led (off 0.1°); AIGFS ran 6° cold.
- Mon Jul 20 3 days out the models said 96–102; it hit 102. ECMWF led (off 0.6°); AIGFS ran 6° cold.
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