Which weather model is most accurate in Charlotte?
Charlotte, North Carolina · daily high temperature in °C · 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 the CLT observations once the day has happened. This page covers the trailing 30 days (2026-08-04 to 2026-09-02), for daily high temperature.
One day out, too close to call; at three days, NOAA AIGFS (AI) (0.94°C); at seven days, NOAA AIGFS (AI) (1.23°C).
The largest standing bias belongs to GEM (Canada), which has run cool by about 2.06°C at 3-day lead over this window.
The Spread's own bias-corrected blend scored a 0.88°C 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) in °C 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 |
|---|---|---|---|---|
| NOAA AIGFS (AI) | 1.0° (+0.3°) | 0.9° (-0.3°) | 1.2° (-0.3°) | 30 |
| ECMWF AIFS (AI) | 1.1° (-1.0°) | 1.4° (-1.2°) | 1.7° (-1.4°) | 30 |
| GEM (Canada) | 1.1° (+0.7°) | 2.2° (-2.1°) | 3.2° (-3.0°) | 30 |
| ECMWF IFS | 1.2° (-0.5°) | 1.4° (+0.0°) | 1.9° (+0.3°) | 30 |
| UKMO (UK) | 1.3° (-0.8°) | 1.6° (-0.9°) | — | 30 |
| DWD ICON | 1.4° (-0.9°) | 1.3° (-0.2°) | — | 30 |
| NOAA GFS | 2.3° (+1.7°) | 2.0° (+1.6°) | 2.9° (+1.5°) | 30 |
| NBM (US blend) | 1.1° (-0.7°) | 1.2° (-0.8°) | 1.4° (-1.2°) | 30 |
| Blended (bias-corrected) | 0.9° (+0.0°) | 0.9° (-0.0°) | 0.9° (-0.0°) | 30 |
Method, honestly
The Spread's Charlotte point is the Charlotte Douglas station (CLT), 10 km from downtown, used for both forecasts and verifications. 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 CLT observations — the station's own daily highs, a thermometer rather than a grid, and no correction applies: the thermometer is the truth outright. 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.
- Tue Sep 1 10 days out the models said 29–34; it hit 36. AIGFS led (off 0.1°C); UKMO ran 2°C cold.
- Mon Aug 31 9 days out the models said 27–32; it hit 33. AIGFS led (off 0.2°C); GFS ran 2°C hot.
- Sun Aug 30 8 days out the models said 26–33; it hit 30. AIFS led (off 0.3°C); GFS ran 3°C hot.
- Sat Aug 29 7 days out the models said 26–34; it hit 31. ECMWF led (off 0.2°C); AIFS ran 2°C cold.
- Fri Aug 28 6 days out the models said 25–33; it hit 32. AIGFS led (off 0.3°C); ICON ran 3°C cold.
- Thu Aug 27 5 days out the models said 26–30; it hit 31. AIGFS led (off 0.4°C); UKMO ran 3°C cold.
- Wed Aug 26 4 days out the models said 29–35; it hit 32. AIGFS led (off 0.1°C); GEM ran 4°C cold.
- Tue Aug 25 3 days out the models said 26–32; it hit 31. ECMWF led (off 0.3°C); UKMO ran 2°C cold.
- Wed Aug 19 13 days out the models said 29–38; it hit 34. ECMWF led (off 0.1°C); GEM ran 2°C hot.
- Tue Aug 18 13 days out the models said 27–35; it hit 34. ICON led (off 0.1°C); GEM ran 2°C hot.
- Mon Aug 17 13 days out the models said 26–34; it hit 36. ICON led (off 0.1°C); GEM ran 3°C hot.
- Sun Aug 16 13 days out the models said 23–33; it hit 36. GFS led (off 0.1°C); ICON ran 3°C cold.
- Sat Aug 15 13 days out the models said 30–37; it hit 35. GFS led (off 0.0°C); ICON ran 2°C cold.
- Fri Aug 14 13 days out the models said 29–35; it hit 35. ECMWF led (off 0.3°C); AIGFS ran 2°C hot.
- Thu Aug 13 13 days out the models said 31–38; it hit 33. ICON led (off 0.0°C); GEM ran 4°C hot.
- Wed Aug 12 13 days out the models said 28–33; it hit 32. ECMWF led (off 0.2°C); GEM ran 3°C hot.
- Tue Aug 11 13 days out the models said 32–37; it hit 33. AIFS led (off 1.6°C); GEM ran 4°C hot.
- Mon Aug 10 13 days out the models said 32–35; it hit 33. AIFS led (off 0.1°C); GEM ran 3°C hot.
- Sun Aug 9 13 days out the models said 29–37; it hit 33. AIFS led (off 0.1°C); GEM ran 3°C hot.
- Sat Aug 8 14 days out the models said 29–37; it hit 32. ECMWF led (off 0.4°C); GEM ran 3°C hot.
- Fri Aug 7 13 days out the models said 29–33; it hit 30. ICON led (off 0.3°C); GEM ran 3°C hot.
- Thu Aug 6 12 days out the models said 29–32; it hit 31. GFS led (off 0.2°C); GEM ran 3°C hot.
- Wed Aug 5 11 days out the models said 29–33; it hit 31. AIGFS led (off 0.2°C); GFS ran 3°C cold.
- Tue Aug 4 10 days out the models said 26–32; it hit 27. ICON led (off 0.1°C); GEM ran 3°C hot.
- Mon Aug 3 9 days out the models said 27–30; it hit 30. ECMWF led (off 0.0°C); UKMO ran 2°C hot.
- Sun Aug 2 8 days out the models said 29–32; it hit 30. AIGFS led (off 0.2°C); ICON ran 2°C cold.
- Sat Aug 1 7 days out the models said 26–31; it hit 30. AIFS led (off 0.7°C); GEM ran 3°C hot.
- Fri Jul 31 6 days out the models said 29–34; it hit 31. AIFS led (off 0.0°C); GEM ran 2°C hot.
- Thu Jul 30 5 days out the models said 29–33; it hit 29. ECMWF led (off 0.2°C); GEM ran 3°C hot.
- Wed Jul 29 4 days out the models said 30–35; it hit 31. ECMWF led (off 0.4°C); GEM ran 3°C hot.
- Tue Jul 28 3 days out the models said 32–36; it hit 33. ECMWF led (off 0.4°C); AIFS ran 2°C cold.
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