Which weather model is most accurate in Charlotte?
Charlotte, North Carolina · daily high temperature · trailing 30 days · refreshed at most every 6 hours
Every day, The Spread archives what each major weather model predicted for Charlotte 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 AIFS (AI) has been most accurate (typical miss 1.26°F); at three days, ECMWF AIFS (AI) (1.2°F); at seven days, ECMWF AIFS (AI) (2.92°F).
The largest standing bias belongs to GEM (Canada), which has run warm by about 4.76°F at 1-day lead over this window.
The Spread's own bias-corrected blend scored a 1.03°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 AIFS (AI) | 1.3° (-0.0°) | 1.2° (-0.6°) | 2.9° (-1.0°) | 30 |
| NOAA AIGFS (AI) | 1.6° (+0.6°) | 2.7° (-1.6°) | 3.8° (-1.7°) | 30 |
| DWD ICON | 1.9° (+0.4°) | 3.3° (+0.6°) | — | 30 |
| ECMWF IFS | 2.0° (+0.8°) | 2.1° (-0.1°) | 3.4° (+1.2°) | 30 |
| UKMO (UK) | 2.1° (+1.8°) | 3.0° (+1.6°) | — | 30 |
| NOAA GFS | 2.6° (+2.4°) | 4.8° (+3.9°) | 6.8° (+5.6°) | 30 |
| GEM (Canada) | 4.9° (+4.8°) | 2.6° (-1.0°) | 4.1° (-0.0°) | 30 |
| NBM (US blend) | 1.6° (-0.1°) | 2.0° (-0.7°) | 3.3° (+1.4°) | 30 |
| Blended (bias-corrected) | 1.0° (+0.0°) | 1.5° (+0.0°) | 2.6° (+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.
- Sun Aug 2 8 days out the models said 85–90; it hit 86. AIGFS led (off 0.4°); ICON ran 4° cold.
- Sat Aug 1 7 days out the models said 79–87; it hit 86. AIFS led (off 1.2°); GEM ran 6° hot.
- Fri Jul 31 6 days out the models said 85–94; it hit 88. AIFS led (off 0.0°); GEM ran 4° hot.
- Thu Jul 30 5 days out the models said 84–92; it hit 84. ECMWF led (off 0.4°); GEM ran 6° hot.
- Wed Jul 29 4 days out the models said 85–94; it hit 88. ECMWF led (off 0.8°); GEM ran 6° hot.
- Tue Jul 28 3 days out the models said 89–98; it hit 91. ECMWF led (off 0.8°); AIFS ran 4° cold.
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