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Which weather model is most accurate in Atlanta?

Forecast Highs Lows Rain Model accuracy

Atlanta, Georgia · daily high temperature in °F · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for Atlanta at 1-, 3-, and 7-day leads, then scores those forecasts against the ATL observations once the day has happened. This page covers the trailing 30 days (2026-09-17 to 2026-10-16), for daily high temperature.

One day out, too close to call; at three days, too close to call; at seven days, too close to call.

The largest standing bias belongs to ECMWF AIFS (AI), which has run cool by about 2.35°F at 1-day lead over this window.

Atlanta's full forecast, every model day by day, with the record on this page beside it. Request an invite; it's free during the beta.

The scoreboard

Typical miss (MAE) in °F with the bias in parentheses. Bias is the mean signed error of the predicted daily high — positive means the model ran warm. A model's high is the warmest of its hourly values and the station's is the warmest it got at any moment, so a model's high reads a little cool, and its low a little warm, even on a day it gets every hour right. ECMWF IFS gives a value only every 3 hours (every 6 past day 6), and ECMWF AIFS (AI) and NOAA AIGFS (AI) only every 6, with the hours between filled in, so their highs read cooler still and their lows warmer. In the forecasts scored here GFS also steps to every 3 hours from day 5, ICON and GEM from day 4, and UKMO from day 3, every 6 by day 6. Days = scored days behind the 1-day number.

Model 1-day 3-day 7-day Days
NOAA AIGFS (AI) 1.7° (-1.1°) 2.6° (-1.4°) 4.6° (-1.6°) 29
DWD ICON 1.9° (-1.3°) 2.1° (-0.7°) — 29
ECMWF IFS 1.9° (-0.7°) 2.0° (+0.2°) 4.1° (-1.5°) 29
UKMO (UK) 2.0° (-1.5°) 2.5° (-1.6°) — 29
ECMWF AIFS (AI) 2.4° (-2.4°) 2.4° (-2.1°) 4.2° (-1.8°) 29
GEM (Canada) 2.5° (-2.2°) 3.3° (-1.5°) 4.8° (-1.8°) 29
NOAA GFS 2.7° (+1.6°) 3.0° (+1.8°) 5.5° (-0.6°) 29

Method, honestly

The Spread's Atlanta point is the Hartsfield-Jackson station (ATL), 9 mi from downtown, used for both forecasts and verifications. Each forecast is the last one The Spread archived on the day it was made, the forecast the model was showing at the time, not a reconstruction. A day the station did not report is left out. Truth is the thermometer at Hartsfield-Jackson (ATL) — 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; consensus products such as the NBM, itself a blend of models, are not scored here. 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.

  • Fri Oct 16 14 days out the models said 56–84; it hit 84. GEM led (off 0.1°F); UKMO ran 3°F cool.
  • Thu Oct 15 14 days out the models said 64–80; it hit 88. GFS led (off 0.2°F); UKMO ran 5°F cool.
  • Wed Oct 14 14 days out the models said 70–82; it hit 87. ICON led (off 0.9°F); UKMO ran 4°F cool.
  • Tue Oct 13 14 days out the models said 62–79; it hit 87. GFS led (off 0.6°F); UKMO ran 4°F cool.
  • Mon Oct 12 14 days out the models said 69–81; it hit 84. GFS led (off 0.9°F); GEM ran 6°F cool.
  • Sun Oct 11 14 days out the models said 62–79; it hit 70. ECMWF led (off 0.2°F); AIGFS ran 3°F cool.
  • Sat Oct 10 14 days out the models said 65–79; it hit 68. UKMO led (off 2.2°F); ECMWF ran 5°F warm.
  • Fri Oct 9 14 days out the models said 59–82; it hit 73. GFS led (off 0.0°F); GEM ran 2°F cool.
  • Thu Oct 8 14 days out the models said 55–72; it hit 85. GFS led (off 0.8°F); UKMO ran 4°F cool.
  • Wed Oct 7 14 days out the models said 70–77; it hit 80. AIGFS led (off 0.3°F); AIFS ran 4°F cool.
  • Tue Oct 6 13 days out the models said 70–75; it hit 78. AIGFS led (off 0.1°F); GEM ran 4°F cool.
  • Mon Oct 5 14 days out the models said 62–84; it hit 76. AIGFS led (off 0.3°F); GEM ran 4°F cool.
  • Sun Oct 4 14 days out the models said 74–81; it hit 78. GFS led (off 3.2°F); GEM ran 6°F cool.
  • Sat Oct 3 14 days out the models said 72–84; it hit 86. GFS led (off 0.9°F); GEM ran 5°F cool.
  • Fri Oct 2 14 days out the models said 73–82; it hit 84. AIFS led (off 0.1°F); GFS ran 4°F warm.
  • Thu Oct 1 14 days out the models said 72–85; it hit 86. ECMWF led (off 0.1°F); GFS ran 3°F warm.
  • Wed Sep 30 14 days out the models said 71–88; it hit 87. AIGFS led (off 0.4°F); AIFS ran 3°F cool.
  • Tue Sep 29 14 days out the models said 68–92; it hit 84. AIGFS led (off 1.0°F); GFS ran 2°F warm.
  • Mon Sep 28 14 days out the models said 81–87; it hit 80. ICON led (off 0.4°F); GFS ran 5°F warm.
  • Sun Sep 27 14 days out the models said 76–90; it hit 81. ICON led (off 0.1°F); GEM ran 4°F cool.
  • Sat Sep 26 14 days out the models said 80–86; it hit 81. ICON led (off 0.7°F); GEM ran 4°F cool.
  • Fri Sep 25 14 days out the models said 68–90; it hit 77. ICON led (off 0.5°F); AIFS ran 5°F cool.
  • Thu Sep 24 14 days out the models said 66–85; it hit 70. GFS led (off 0.7°F); ECMWF ran 5°F warm.
  • Wed Sep 23 14 days out the models said 72–86; it hit 82. ECMWF led (off 2.7°F); AIGFS ran 8°F cool.
  • Tue Sep 22 14 days out the models said 68–94; it hit 86. AIFS led (off 0.5°F); GFS ran 6°F warm.
  • Mon Sep 21 14 days out the models said 74–88; it hit 90. AIGFS led (off 0.4°F); GFS ran 5°F warm.
  • Sun Sep 20 14 days out the models said 74–79; it hit 89. AIGFS led (off 0.3°F); ICON ran 7°F cool.
  • Sat Sep 19 14 days out the models said 81–87; it hit 92. UKMO led (off 0.4°F); GFS ran 4°F warm.
  • Fri Sep 18 14 days out the models said 78–94; it hit 93. GEM led (off 0.2°F); GFS ran 5°F warm.
  • Thu Sep 17 14 days out the models said 76–102; it hit 90. AIGFS led (off 0.5°F); GFS ran 3°F warm.
  • Wed Sep 16 14 days out the models said 88–95; it hit 89. AIGFS led (off 0.6°F); UKMO ran 3°F cool.
  • Tue Sep 15 14 days out the models said 76–91; it hit 90. AIFS led (off 0.1°F); UKMO ran 5°F cool.
  • Mon Sep 14 14 days out the models said 81–96; it hit 93. ECMWF led (off 0.1°F); GFS ran 3°F warm.
  • Sun Sep 13 14 days out the models said 90–92; it hit 90. UKMO led (off 0.1°F); GEM ran 5°F cool.
  • Sat Sep 12 14 days out the models said 87–98; it hit 85. ICON led (off 1.0°F); AIFS ran 4°F cool.
  • Fri Sep 11 14 days out the models said 79–90; it hit 88. GEM led (off 0.2°F); GFS ran 5°F warm.
  • Thu Sep 10 14 days out the models said 82–105; it hit 91. GEM led (off 0.6°F); UKMO ran 4°F cool.
  • Wed Sep 9 14 days out the models said 86–94; it hit 89. GEM led (off 0.1°F).
  • Tue Sep 8 14 days out the models said 79–98; it hit 88. ECMWF led (off 0.1°F); GEM ran 4°F cool.
  • Mon Sep 7 14 days out the models said 82–97; it hit 83. ICON led (off 0.0°F); GFS ran 4°F warm.
  • Sun Sep 6 14 days out the models said 92–98; it hit 95. AIGFS led (off 0.0°F); GFS ran 4°F warm.
  • Sat Sep 5 14 days out the models said 80–91; it hit 97. UKMO led (off 0.1°F); GFS ran 6°F warm.
  • Fri Sep 4 14 days out the models said 81–104; it hit 95. AIGFS led (off 0.9°F); GEM ran 4°F cool.
  • Thu Sep 3 13 days out the models said 91–102; it hit 96. AIGFS led (off 0.1°F); GFS ran 4°F warm.
  • Wed Sep 2 12 days out the models said 90–102; it hit 95. AIGFS led (off 0.0°F); GFS ran 4°F warm.
  • Tue Sep 1 11 days out the models said 88–98; it hit 94. ECMWF led (off 0.3°F); UKMO ran 3°F cool.
  • Mon Aug 31 10 days out the models said 85–96; it hit 94. GFS led (off 1.0°F); UKMO ran 5°F cool.
  • Sun Aug 30 9 days out the models said 82–96; it hit 91. GFS led (off 0.2°F); GEM ran 5°F cool.
  • Sat Aug 29 8 days out the models said 85–96; it hit 89. GFS led (off 0.4°F); UKMO ran 5°F cool.
  • Fri Aug 28 7 days out the models said 85–94; it hit 93. GFS led (off 0.7°F); GEM ran 7°F cool.
  • Thu Aug 27 6 days out the models said 75–88; it hit 89. AIGFS led (off 0.8°F); ICON ran 7°F cool.
  • Wed Aug 26 5 days out the models said 86–88; it hit 91. AIGFS led (off 0.1°F); AIFS ran 4°F cool.
  • Tue Aug 25 4 days out the models said 83–93; it hit 94. ECMWF led (off 0.5°F); GEM ran 5°F cool.
  • Wed Aug 19 14 days out the models said 86–100; it hit 95. ECMWF led (off 0.1°F); AIFS ran 6°F cool.
  • Tue Aug 18 14 days out the models said 74–93; it hit 92. GEM led (off 0.7°F); ECMWF ran 3°F warm.
  • Mon Aug 17 14 days out the models said 83–97; it hit 98. UKMO led (off 0.3°F); AIFS ran 4°F cool.
  • Sun Aug 16 14 days out the models said 86–100; it hit 97. UKMO led (off 0.1°F); AIFS ran 4°F cool.
  • Sat Aug 15 14 days out the models said 89–97; it hit 94. ICON led (off 0.5°F); UKMO ran 4°F warm.
  • Fri Aug 14 14 days out the models said 84–97; it hit 93. ECMWF led (off 0.1°F); UKMO ran 4°F warm.
  • Thu Aug 13 14 days out the models said 81–98; it hit 92. AIGFS led (off 0.0°F); GFS ran 5°F warm.
  • Wed Aug 12 14 days out the models said 82–90; it hit 90. AIFS led (off 0.0°F); UKMO ran 4°F warm.
  • Tue Aug 11 14 days out the models said 86–101; it hit 88. UKMO led (off 0.0°F); GFS ran 4°F warm.
  • Mon Aug 10 14 days out the models said 91–96; it hit 89. AIFS led (off 0.3°F); GEM ran 2°F warm.
  • Sun Aug 9 14 days out the models said 84–90; it hit 91. AIGFS led (off 0.0°F); GFS ran 4°F cool.
  • Sat Aug 8 13 days out the models said 83–91; it hit 89. GEM led (off 0.0°F); UKMO ran 3°F warm.
  • Fri Aug 7 12 days out the models said 85–93; it hit 84. AIGFS led (off 1.1°F); GFS ran 4°F warm.
  • Thu Aug 6 11 days out the models said 85–96; it hit 86. GEM led (off 0.0°F); GFS ran 3°F cool.
  • Wed Aug 5 10 days out the models said 87–94; it hit 86. AIGFS led (off 1.0°F); GEM ran 4°F cool.
  • Tue Aug 4 9 days out the models said 81–90; it hit 86. AIGFS led (off 0.9°F); ECMWF ran 6°F cool.
  • Mon Aug 3 8 days out the models said 80–84; it hit 83. AIGFS led (off 0.2°F).
  • Sun Aug 2 7 days out the models said 81–84; it hit 88. GFS led (off 0.8°F); UKMO ran 5°F warm.
  • Sat Aug 1 6 days out the models said 76–96; it hit 87. GFS led (off 0.8°F); ICON ran 8°F cool.
  • Fri Jul 31 5 days out the models said 86–94; it hit 90. AIGFS led (off 0.6°F); GFS ran 4°F warm.
  • Thu Jul 30 4 days out the models said 84–94; it hit 90. GFS led (off 0.1°F); GEM ran 5°F cool.

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