Which weather model is most accurate in Charlotte?
Charlotte, North Carolina · daily high temperature in °F · 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) (1.7°F); at seven days, NOAA AIGFS (AI) (2.21°F).
The largest standing bias belongs to GEM (Canada), which has run cool by about 3.7°F at 3-day lead over this window.
The Spread's own bias-corrected blend scored a 1.58°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) in °F 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) | 1.8° (+0.5°) | 1.7° (-0.5°) | 2.2° (-0.6°) | 30 |
| ECMWF AIFS (AI) | 2.0° (-1.9°) | 2.5° (-2.2°) | 3.1° (-2.5°) | 30 |
| GEM (Canada) | 2.0° (+1.2°) | 4.0° (-3.7°) | 5.7° (-5.4°) | 30 |
| ECMWF IFS | 2.2° (-0.8°) | 2.6° (+0.0°) | 3.4° (+0.5°) | 30 |
| UKMO (UK) | 2.4° (-1.4°) | 2.8° (-1.6°) | — | 30 |
| DWD ICON | 2.5° (-1.7°) | 2.4° (-0.3°) | — | 30 |
| NOAA GFS | 4.1° (+3.1°) | 3.6° (+3.0°) | 5.2° (+2.6°) | 30 |
| NBM (US blend) | 2.0° (-1.2°) | 2.2° (-1.4°) | 2.6° (-2.2°) | 30 |
| Blended (bias-corrected) | 1.6° (+0.0°) | 1.6° (-0.0°) | 1.6° (-0.0°) | 30 |
Method, honestly
The Spread's Charlotte point is the Charlotte Douglas station (CLT), 6 mi 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 84–93; it hit 96. AIGFS led (off 0.1°F); UKMO ran 4°F cold.
- Mon Aug 31 9 days out the models said 81–90; it hit 92. AIGFS led (off 0.3°F); GFS ran 4°F hot.
- Sun Aug 30 8 days out the models said 78–91; it hit 86. AIFS led (off 0.6°F); GFS ran 6°F hot.
- Sat Aug 29 7 days out the models said 80–93; it hit 88. ECMWF led (off 0.4°F); AIFS ran 4°F cold.
- Fri Aug 28 6 days out the models said 77–91; it hit 90. AIGFS led (off 0.6°F); ICON ran 6°F cold.
- Thu Aug 27 5 days out the models said 78–87; it hit 88. AIGFS led (off 0.7°F); UKMO ran 6°F cold.
- Wed Aug 26 4 days out the models said 84–94; it hit 89. AIGFS led (off 0.2°F); GEM ran 8°F cold.
- Tue Aug 25 3 days out the models said 79–89; it hit 88. ECMWF led (off 0.6°F); UKMO ran 4°F cold.
- Wed Aug 19 13 days out the models said 84–101; it hit 94. ECMWF led (off 0.1°F); GEM ran 4°F hot.
- Tue Aug 18 13 days out the models said 81–96; it hit 93. ICON led (off 0.2°F); GEM ran 4°F hot.
- Mon Aug 17 13 days out the models said 78–94; it hit 97. ICON led (off 0.1°F); GEM ran 5°F hot.
- Sun Aug 16 13 days out the models said 74–92; it hit 96. GFS led (off 0.1°F); ICON ran 5°F cold.
- Sat Aug 15 13 days out the models said 86–98; it hit 95. GFS led (off 0.0°F); ICON ran 3°F cold.
- Fri Aug 14 13 days out the models said 84–96; it hit 94. ECMWF led (off 0.5°F); AIGFS ran 4°F hot.
- Thu Aug 13 13 days out the models said 88–101; it hit 92. ICON led (off 0.0°F); GEM ran 6°F hot.
- Wed Aug 12 13 days out the models said 83–92; it hit 90. ECMWF led (off 0.3°F); GEM ran 6°F hot.
- Tue Aug 11 13 days out the models said 89–99; it hit 92. AIFS led (off 2.8°F); GEM ran 7°F hot.
- Mon Aug 10 13 days out the models said 89–95; it hit 91. AIFS led (off 0.2°F); GEM ran 5°F hot.
- Sun Aug 9 13 days out the models said 84–99; it hit 91. AIFS led (off 0.1°F); GEM ran 5°F hot.
- Sat Aug 8 14 days out the models said 83–98; it hit 89. ECMWF led (off 0.7°F); GEM ran 6°F hot.
- Fri Aug 7 13 days out the models said 84–91; it hit 87. ICON led (off 0.6°F); GEM ran 5°F hot.
- Thu Aug 6 12 days out the models said 84–90; it hit 88. GFS led (off 0.3°F); GEM ran 5°F hot.
- Wed Aug 5 11 days out the models said 84–92; it hit 87. AIGFS led (off 0.4°F); GFS ran 5°F cold.
- Tue Aug 4 10 days out the models said 78–90; it hit 81. ICON led (off 0.2°F); GEM ran 5°F hot.
- Mon Aug 3 9 days out the models said 80–87; it hit 86. ECMWF led (off 0.0°F); UKMO ran 4°F hot.
- Sun Aug 2 8 days out the models said 85–90; it hit 86. AIGFS led (off 0.4°F); ICON ran 4°F cold.
- Sat Aug 1 7 days out the models said 79–87; it hit 86. AIFS led (off 1.2°F); GEM ran 6°F hot.
- Fri Jul 31 6 days out the models said 85–94; it hit 88. AIFS led (off 0.0°F); GEM ran 4°F hot.
- Thu Jul 30 5 days out the models said 84–92; it hit 84. ECMWF led (off 0.4°F); GEM ran 6°F hot.
- Wed Jul 29 4 days out the models said 85–94; it hit 88. ECMWF led (off 0.8°F); GEM ran 6°F hot.
- Tue Jul 28 3 days out the models said 89–98; it hit 91. ECMWF led (off 0.8°F); AIFS ran 4°F cold.
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