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Which weather model is most accurate in St. Louis?

Forecast Highs Lows Rain Model accuracy

St. Louis, Missouri · daily high temperature in °F · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for St. Louis at 1-, 3-, and 7-day leads, then scores those forecasts against the STL 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, ECMWF IFS (7°F).

The largest standing bias belongs to UKMO (UK), which has run cool by about 2.65°F at 3-day lead over this window.

St. Louis'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 GFS 2.5° (+1.1°) 3.2° (+2.1°) 7.8° (+0.4°) 29
DWD ICON 2.5° (-0.9°) 3.0° (-2.0°) — 29
ECMWF AIFS (AI) 2.6° (-2.0°) 2.8° (-2.3°) 8.0° (-5.9°) 29
NOAA AIGFS (AI) 2.6° (-2.2°) 3.2° (-2.4°) 7.6° (-4.0°) 29
GEM (Canada) 2.7° (+2.0°) 3.2° (-0.4°) 7.6° (-4.1°) 29
UKMO (UK) 3.3° (-2.2°) 4.0° (-2.6°) — 29
ECMWF IFS 3.4° (-1.9°) 3.3° (-1.3°) 7.0° (-3.8°) 29

Method, honestly

The Spread's St. Louis point is the Lambert station (STL), 13 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 Lambert (STL) — 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 50–67; it hit 59. AIGFS led (off 0.3°F); ECMWF ran 11°F warm.
  • Thu Oct 15 14 days out the models said 67–76; it hit 82. GFS led (off 0.4°F); AIFS ran 6°F cool.
  • Wed Oct 14 14 days out the models said 57–83; it hit 79. ICON led (off 0.1°F); GEM ran 5°F warm.
  • Tue Oct 13 14 days out the models said 60–75; it hit 93. ECMWF led (off 0.0°F); UKMO ran 3°F cool.
  • Mon Oct 12 14 days out the models said 64–88; it hit 92. ICON led (off 0.1°F); AIGFS ran 4°F cool.
  • Sun Oct 11 14 days out the models said 63–77; it hit 87. GFS led (off 0.4°F); UKMO ran 5°F cool.
  • Sat Oct 10 14 days out the models said 62–76; it hit 79. UKMO led (off 0.1°F); GEM ran 5°F warm.
  • Fri Oct 9 14 days out the models said 64–75; it hit 88. ICON led (off 1.2°F); ECMWF ran 3°F cool.
  • Thu Oct 8 14 days out the models said 62–74; it hit 85. GFS led (off 0.3°F); UKMO ran 7°F cool.
  • Wed Oct 7 14 days out the models said 65–77; it hit 89. AIFS led (off 1.7°F); UKMO ran 6°F cool.
  • Tue Oct 6 13 days out the models said 66–75; it hit 78. AIFS led (off 0.2°F); UKMO ran 3°F cool.
  • Mon Oct 5 14 days out the models said 64–80; it hit 76. ICON led (off 0.4°F); UKMO ran 4°F cool.
  • Sun Oct 4 14 days out the models said 69–79; it hit 82. GFS led (off 1.5°F); ECMWF ran 6°F cool.
  • Sat Oct 3 14 days out the models said 60–80; it hit 73. AIGFS led (off 0.1°F); GFS ran 4°F warm.
  • Fri Oct 2 14 days out the models said 81–86; it hit 74. GEM led (off 0.2°F); AIGFS ran 5°F cool.
  • Thu Oct 1 14 days out the models said 72–84; it hit 90. GEM led (off 2.1°F); ECMWF ran 13°F cool.
  • Wed Sep 30 14 days out the models said 68–92; it hit 92. ICON led (off 0.2°F); AIFS ran 4°F cool.
  • Tue Sep 29 14 days out the models said 70–86; it hit 84. ICON led (off 0.1°F); ECMWF ran 4°F cool.
  • Mon Sep 28 14 days out the models said 71–95; it hit 80. GEM led (off 0.8°F); ECMWF ran 6°F cool.
  • Sun Sep 27 14 days out the models said 74–90; it hit 74. UKMO led (off 0.1°F); GEM ran 7°F warm.
  • Sat Sep 26 14 days out the models said 72–92; it hit 69. ICON led (off 0.3°F); GEM ran 9°F warm.
  • Fri Sep 25 14 days out the models said 68–96; it hit 72. ICON led (off 0.6°F); GEM ran 7°F warm.
  • Thu Sep 24 14 days out the models said 63–88; it hit 70. UKMO led (off 0.8°F); GEM ran 9°F warm.
  • Wed Sep 23 14 days out the models said 68–93; it hit 70. ECMWF led (off 0.7°F); GFS ran 6°F warm.
  • Tue Sep 22 14 days out the models said 72–79; it hit 72. ECMWF led (off 0.7°F); AIFS ran 6°F cool.
  • Mon Sep 21 14 days out the models said 72–87; it hit 73. AIFS led (off 0.0°F); GEM ran 4°F warm.
  • Sun Sep 20 14 days out the models said 66–76; it hit 92. GEM led (off 0.2°F); UKMO ran 6°F cool.
  • Sat Sep 19 14 days out the models said 62–88; it hit 97. GFS led (off 0.4°F); UKMO ran 4°F cool.
  • Fri Sep 18 14 days out the models said 78–81; it hit 98. GFS led (off 0.4°F); AIFS ran 6°F cool.
  • Thu Sep 17 14 days out the models said 71–109; it hit 99. GFS led (off 1.0°F); AIGFS ran 6°F cool.
  • Wed Sep 16 14 days out the models said 76–102; it hit 94. ECMWF led (off 1.2°F); AIFS ran 5°F cool.
  • Tue Sep 15 14 days out the models said 74–96; it hit 98. ECMWF led (off 0.3°F); GFS ran 3°F warm.
  • Mon Sep 14 14 days out the models said 78–99; it hit 88. GFS led (off 0.6°F); UKMO ran 4°F cool.
  • Sun Sep 13 14 days out the models said 90–99; it hit 86. AIFS led (off 2.4°F); ICON ran 9°F cool.
  • Sat Sep 12 14 days out the models said 81–96; it hit 92. ICON led (off 1.1°F); ECMWF ran 6°F cool.
  • Fri Sep 11 14 days out the models said 85–96; it hit 83. ECMWF led (off 0.4°F); AIFS ran 4°F cool.
  • Thu Sep 10 14 days out the models said 84–110; it hit 80. GEM led (off 1.4°F); GFS ran 7°F cool.
  • Wed Sep 9 14 days out the models said 82–93; it hit 93. AIFS led (off 0.9°F); GFS ran 12°F warm.
  • Tue Sep 8 14 days out the models said 80–103; it hit 93. AIFS led (off 0.1°F); GEM ran 5°F warm.
  • Mon Sep 7 13 days out the models said 74–100; it hit 87. ECMWF led (off 0.5°F); GEM ran 5°F warm.
  • Sun Sep 6 12 days out the models said 79–94; it hit 90. ECMWF led (off 0.3°F); GEM ran 6°F warm.
  • Sat Sep 5 11 days out the models said 89–98; it hit 101. AIGFS led (off 0.1°F); GFS ran 5°F warm.
  • Fri Sep 4 10 days out the models said 85–103; it hit 100. AIGFS led (off 0.4°F); UKMO ran 4°F cool.
  • Thu Sep 3 9 days out the models said 94–103; it hit 99. ICON led (off 0.0°F); GFS ran 4°F warm.
  • Wed Sep 2 8 days out the models said 93–103; it hit 100. AIGFS led (off 0.7°F); GFS ran 4°F warm.
  • Tue Sep 1 7 days out the models said 92–102; it hit 100. ICON led (off 0.5°F); GEM ran 4°F warm.
  • Mon Aug 31 6 days out the models said 81–103; it hit 99. ICON led (off 0.0°F); GEM ran 3°F warm.
  • Sun Aug 30 5 days out the models said 89–100; it hit 96. GEM led (off 1.4°F); AIGFS ran 4°F cool.
  • Sat Aug 29 4 days out the models said 82–94; it hit 88. UKMO led (off 0.4°F); GFS ran 6°F warm.
  • Fri Aug 28 3 days out the models said 84–88; it hit 87. GFS led (off 0.9°F); ECMWF ran 3°F cool.

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