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Which weather model is most accurate in Salt Lake City?

Forecast Highs Lows Rain Model accuracy

Salt Lake City, Utah · daily high temperature in °F · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for Salt Lake City at 1-, 3-, and 7-day leads, then scores those forecasts against the SLC 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 3.34°F at 3-day lead over this window.

Salt Lake City'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 1.6° (+0.3°) 2.7° (+1.5°) 5.2° (+2.3°) 29
DWD ICON 1.9° (-1.4°) 2.6° (-1.3°) 4.2° (-0.0°) 29
UKMO (UK) 2.4° (-2.1°) 2.9° (-1.8°) — 29
ECMWF IFS 2.7° (-2.5°) 2.6° (-1.4°) 3.4° (-0.0°) 29
GEM (Canada) 2.9° (-2.3°) 3.6° (-2.7°) 4.6° (-2.6°) 29
ECMWF AIFS (AI) 2.9° (-2.8°) 3.4° (-3.3°) 3.3° (-1.2°) 29
NOAA AIGFS (AI) 3.3° (-3.1°) 2.8° (-2.0°) 5.4° (-2.8°) 29

Method, honestly

The Spread's Salt Lake City point is the Salt Lake City International station (SLC), 4.4 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 Salt Lake City International (SLC) — 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 55–86; it hit 67. GFS led (off 1.0°F); GEM ran 4°F cool.
  • Thu Oct 15 14 days out the models said 50–81; it hit 63. AIFS led (off 0.9°F); GEM ran 6°F cool.
  • Wed Oct 14 14 days out the models said 61–78; it hit 56. GFS led (off 0.7°F); GEM ran 2°F cool.
  • Tue Oct 13 14 days out the models said 73–79; it hit 51. UKMO led (off 0.0°F); GEM ran 2°F cool.
  • Mon Oct 12 14 days out the models said 76–82; it hit 58. ECMWF led (off 0.6°F); GFS ran 4°F warm.
  • Sun Oct 11 14 days out the models said 75–79; it hit 70. UKMO led (off 0.2°F); AIFS ran 6°F cool.
  • Sat Oct 10 14 days out the models said 66–83; it hit 79. ICON led (off 0.3°F); UKMO ran 6°F cool.
  • Fri Oct 9 14 days out the models said 74–80; it hit 83. ICON led (off 0.8°F); GFS ran 2°F warm.
  • Thu Oct 8 14 days out the models said 74–83; it hit 84. ECMWF led (off 0.2°F); AIGFS ran 5°F cool.
  • Wed Oct 7 14 days out the models said 73–79; it hit 82. AIFS led (off 0.5°F); GEM ran 4°F cool.
  • Tue Oct 6 14 days out the models said 60–78; it hit 79. AIGFS led (off 1.0°F); ICON ran 4°F warm.
  • Mon Oct 5 14 days out the models said 79–86; it hit 88. GFS led (off 0.2°F); AIGFS ran 4°F cool.
  • Sun Oct 4 14 days out the models said 53–75; it hit 86. ECMWF led (off 0.1°F); GEM ran 3°F cool.
  • Sat Oct 3 14 days out the models said 66–83; it hit 84. GFS led (off 0.7°F); GEM ran 6°F cool.
  • Fri Oct 2 14 days out the models said 60–87; it hit 85. GFS led (off 0.4°F); UKMO ran 4°F cool.
  • Thu Oct 1 14 days out the models said 53–77; it hit 80. GFS led (off 1.4°F); AIGFS ran 5°F cool.
  • Wed Sep 30 14 days out the models said 66–76; it hit 76. AIFS led (off 1.9°F); AIGFS ran 5°F cool.
  • Tue Sep 29 14 days out the models said 74–86; it hit 75. GEM led (off 0.9°F); AIGFS ran 6°F cool.
  • Mon Sep 28 14 days out the models said 59–85; it hit 73. ICON led (off 0.3°F); ECMWF ran 6°F cool.
  • Sun Sep 27 14 days out the models said 70–88; it hit 85. GFS led (off 1.7°F); AIGFS ran 4°F cool.
  • Sat Sep 26 14 days out the models said 68–90; it hit 80. AIFS led (off 1.0°F); AIGFS ran 3°F cool.
  • Fri Sep 25 14 days out the models said 72–81; it hit 85. GFS led (off 0.8°F); UKMO ran 4°F cool.
  • Thu Sep 24 14 days out the models said 68–88; it hit 81. GFS led (off 0.2°F); GEM ran 5°F cool.
  • Wed Sep 23 14 days out the models said 74–81; it hit 76. UKMO led (off 0.4°F); AIGFS ran 2°F cool.
  • Tue Sep 22 14 days out the models said 64–84; it hit 76. GFS led (off 0.5°F); AIFS ran 10°F cool.
  • Mon Sep 21 14 days out the models said 73–81; it hit 78. UKMO led (off 0.1°F); AIGFS ran 3°F cool.
  • Sun Sep 20 14 days out the models said 72–87; it hit 72. ICON led (off 0.2°F); AIGFS ran 3°F cool.
  • Sat Sep 19 14 days out the models said 85–87; it hit 70. ICON led (off 0.2°F); GEM ran 3°F cool.
  • Fri Sep 18 14 days out the models said 74–92; it hit 82. GFS led (off 1.7°F); ECMWF ran 13°F cool.
  • Thu Sep 17 14 days out the models said 57–91; it hit 86. ECMWF led (off 2.3°F); UKMO ran 6°F cool.
  • Wed Sep 16 14 days out the models said 57–87; it hit 89. GFS led (off 1.9°F); ECMWF ran 7°F cool.
  • Tue Sep 15 14 days out the models said 70–92; it hit 78. ICON led (off 0.2°F); GFS ran 4°F warm.
  • Mon Sep 14 14 days out the models said 61–85; it hit 72. ECMWF led (off 0.0°F); AIGFS ran 4°F cool.
  • Sun Sep 13 14 days out the models said 68–87; it hit 93. GFS led (off 0.9°F); GEM ran 9°F cool.
  • Sat Sep 12 14 days out the models said 78–90; it hit 91. AIFS led (off 0.9°F); AIGFS ran 3°F cool.
  • Fri Sep 11 14 days out the models said 78–90; it hit 89. AIFS led (off 1.7°F); UKMO ran 5°F cool.
  • Thu Sep 10 14 days out the models said 80–93; it hit 89. ECMWF led (off 1.6°F); AIGFS ran 4°F cool.
  • Wed Sep 9 14 days out the models said 70–88; it hit 85. ECMWF led (off 0.7°F); AIGFS ran 5°F cool.
  • Tue Sep 8 14 days out the models said 87–92; it hit 83. AIFS led (off 1.7°F); AIGFS ran 5°F cool.
  • Mon Sep 7 14 days out the models said 80–92; it hit 77. AIFS led (off 1.1°F); AIGFS ran 4°F cool.
  • Sun Sep 6 14 days out the models said 59–84; it hit 89. GEM led (off 0.5°F); UKMO ran 7°F cool.
  • Sat Sep 5 14 days out the models said 78–90; it hit 91. GFS led (off 1.4°F); GEM ran 3°F cool.
  • Fri Sep 4 14 days out the models said 80–97; it hit 90. AIGFS led (off 0.2°F); ECMWF ran 3°F cool.
  • Thu Sep 3 14 days out the models said 88–96; it hit 87. GFS led (off 0.8°F); UKMO ran 3°F cool.
  • Wed Sep 2 13 days out the models said 79–96; it hit 87. GFS led (off 0.5°F); AIFS ran 5°F cool.
  • Tue Sep 1 12 days out the models said 84–90; it hit 84. ICON led (off 0.7°F); AIFS ran 5°F cool.
  • Mon Aug 31 11 days out the models said 79–96; it hit 87. GEM led (off 0.9°F); AIFS ran 10°F cool.
  • Sun Aug 30 10 days out the models said 77–98; it hit 82. GFS led (off 0.9°F); ECMWF ran 9°F cool.
  • Sat Aug 29 9 days out the models said 78–98; it hit 75. AIGFS led (off 1.3°F); GEM ran 7°F cool.
  • Fri Aug 28 8 days out the models said 84–98; it hit 92. GEM led (off 0.3°F); UKMO ran 8°F cool.
  • Thu Aug 27 7 days out the models said 90–97; it hit 97. GEM led (off 1.3°F); AIFS ran 6°F cool.
  • Wed Aug 26 6 days out the models said 91–99; it hit 96. GEM led (off 1.0°F); AIFS ran 4°F cool.
  • Tue Aug 25 5 days out the models said 88–94; it hit 94. ECMWF led (off 0.9°F); ICON ran 4°F cool.
  • Mon Aug 24 4 days out the models said 88–96; it hit 95. ICON led (off 0.8°F); AIFS ran 8°F cool.
  • Sun Aug 23 3 days out the models said 91–95; it hit 94. UKMO led (off 1.0°F); ECMWF ran 3°F cool.
  • Tue Aug 18 14 days out the models said 78–96; it hit 94. ECMWF led (off 0.3°F); AIGFS ran 4°F cool.
  • Mon Aug 17 14 days out the models said 78–97; it hit 96. GFS led (off 1.0°F); UKMO ran 4°F cool.
  • Sun Aug 16 14 days out the models said 77–89; it hit 91. GEM led (off 0.5°F); ECMWF ran 5°F cool.
  • Sat Aug 15 14 days out the models said 80–97; it hit 83. AIFS led (off 0.3°F); GFS ran 4°F warm.
  • Fri Aug 14 14 days out the models said 80–106; it hit 78. ICON led (off 0.7°F); GFS ran 6°F warm.
  • Thu Aug 13 14 days out the models said 80–98; it hit 75. ICON led (off 0.8°F); GFS ran 5°F warm.
  • Wed Aug 12 14 days out the models said 85–101; it hit 88. GFS led (off 0.8°F); AIFS ran 6°F cool.
  • Tue Aug 11 14 days out the models said 83–97; it hit 97. GFS led (off 0.6°F); AIFS ran 6°F cool.
  • Mon Aug 10 14 days out the models said 93–99; it hit 98. ICON led (off 0.4°F); AIFS ran 4°F cool.
  • Sun Aug 9 14 days out the models said 93–100; it hit 100. GEM led (off 0.0°F); AIFS ran 6°F cool.
  • Sat Aug 8 14 days out the models said 92–104; it hit 103. GFS led (off 0.7°F); AIFS ran 5°F cool.
  • Fri Aug 7 14 days out the models said 84–102; it hit 104. ECMWF led (off 0.0°F); GEM ran 4°F cool.
  • Thu Aug 6 14 days out the models said 90–100; it hit 101. GFS led (off 0.7°F); GEM ran 4°F cool.
  • Wed Aug 5 14 days out the models said 89–106; it hit 95. GFS led (off 0.1°F); AIGFS ran 4°F cool.
  • Tue Aug 4 14 days out the models said 99–105; it hit 91. ECMWF led (off 0.3°F); AIGFS ran 4°F cool.
  • Mon Aug 3 14 days out the models said 83–105; it hit 91. GFS led (off 0.2°F); ICON ran 3°F cool.
  • Sun Aug 2 14 days out the models said 99–101; it hit 101. GFS led (off 0.0°F); AIGFS ran 3°F cool.
  • Sat Aug 1 14 days out the models said 94–102; it hit 105. ECMWF led (off 0.2°F); GEM ran 4°F cool.
  • Fri Jul 31 14 days out the models said 94–102; it hit 102. ECMWF led (off 0.4°F); GEM ran 3°F cool.
  • Thu Jul 30 13 days out the models said 93–101; it hit 95. GEM led (off 0.0°F); GFS ran 4°F warm.
  • Wed Jul 29 12 days out the models said 93–102; it hit 93. ICON led (off 0.0°F); AIFS ran 5°F cool.
  • Tue Jul 28 11 days out the models said 88–101; it hit 95. UKMO led (off 0.3°F); GEM ran 4°F warm.
  • Mon Jul 27 10 days out the models said 92–100; it hit 96. ICON led (off 0.7°F); GFS ran 5°F warm.
  • Sun Jul 26 9 days out the models said 89–98; it hit 101. ECMWF led (off 0.0°F); GFS ran 3°F warm.
  • Sat Jul 25 8 days out the models said 81–95; it hit 102. GFS led (off 0.1°F); AIGFS ran 4°F cool.
  • Fri Jul 24 7 days out the models said 82–100; it hit 99. ECMWF led (off 0.8°F); GFS ran 3°F warm.
  • Thu Jul 23 6 days out the models said 76–96; it hit 96. GFS led (off 0.0°F); ECMWF ran 5°F cool.
  • Wed Jul 22 5 days out the models said 82–98; it hit 87. ICON led (off 0.8°F); GEM ran 4°F warm.
  • Tue Jul 21 4 days out the models said 90–98; it hit 99. UKMO led (off 0.9°F); AIGFS ran 7°F cool.
  • Mon Jul 20 3 days out the models said 97–103; it hit 102. GFS led (off 0.7°F); AIFS ran 5°F cool.

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