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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 °C · 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 1.86°C 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 °C 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 0.9° (+0.2°) 1.5° (+0.8°) 2.9° (+1.3°) 29
DWD ICON 1.1° (-0.8°) 1.4° (-0.7°) 2.3° (-0.0°) 29
UKMO (UK) 1.3° (-1.2°) 1.6° (-1.0°) — 29
ECMWF IFS 1.5° (-1.4°) 1.4° (-0.8°) 1.9° (-0.0°) 29
GEM (Canada) 1.6° (-1.3°) 2.0° (-1.5°) 2.6° (-1.4°) 29
ECMWF AIFS (AI) 1.6° (-1.6°) 1.9° (-1.9°) 1.8° (-0.7°) 29
NOAA AIGFS (AI) 1.9° (-1.7°) 1.6° (-1.1°) 3.0° (-1.5°) 29

Method, honestly

The Spread's Salt Lake City point is the Salt Lake City International station (SLC), 7.1 km 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 13–30; it hit 19. GFS led (off 0.6°C); GEM ran 2°C cool.
  • Thu Oct 15 14 days out the models said 10–27; it hit 17. AIFS led (off 0.5°C); GEM ran 3°C cool.
  • Wed Oct 14 14 days out the models said 16–26; it hit 13. GFS led (off 0.4°C); GEM ran 1°C cool.
  • Tue Oct 13 14 days out the models said 23–26; it hit 11. UKMO led (off 0.0°C); GEM ran 1°C cool.
  • Mon Oct 12 14 days out the models said 24–28; it hit 14. ECMWF led (off 0.3°C); GFS ran 2°C warm.
  • Sun Oct 11 14 days out the models said 24–26; it hit 21. UKMO led (off 0.1°C); AIFS ran 3°C cool.
  • Sat Oct 10 14 days out the models said 19–28; it hit 26. ICON led (off 0.2°C); UKMO ran 3°C cool.
  • Fri Oct 9 14 days out the models said 24–26; it hit 28. ICON led (off 0.4°C); GFS ran 1°C warm.
  • Thu Oct 8 14 days out the models said 23–28; it hit 29. ECMWF led (off 0.1°C); AIGFS ran 3°C cool.
  • Wed Oct 7 14 days out the models said 23–26; it hit 28. AIFS led (off 0.3°C); GEM ran 2°C cool.
  • Tue Oct 6 14 days out the models said 15–26; it hit 26. AIGFS led (off 0.6°C); ICON ran 2°C warm.
  • Mon Oct 5 14 days out the models said 26–30; it hit 31. GFS led (off 0.1°C); AIGFS ran 2°C cool.
  • Sun Oct 4 14 days out the models said 12–24; it hit 30. ECMWF led (off 0.1°C); GEM ran 2°C cool.
  • Sat Oct 3 14 days out the models said 19–28; it hit 29. GFS led (off 0.4°C); GEM ran 3°C cool.
  • Fri Oct 2 14 days out the models said 15–30; it hit 29. GFS led (off 0.2°C); UKMO ran 2°C cool.
  • Thu Oct 1 14 days out the models said 12–25; it hit 27. GFS led (off 0.8°C); AIGFS ran 3°C cool.
  • Wed Sep 30 14 days out the models said 19–25; it hit 24. AIFS led (off 1.1°C); AIGFS ran 3°C cool.
  • Tue Sep 29 14 days out the models said 23–30; it hit 24. GEM led (off 0.5°C); AIGFS ran 3°C cool.
  • Mon Sep 28 14 days out the models said 15–29; it hit 23. ICON led (off 0.2°C); ECMWF ran 4°C cool.
  • Sun Sep 27 14 days out the models said 21–31; it hit 29. GFS led (off 0.9°C); AIGFS ran 2°C cool.
  • Sat Sep 26 14 days out the models said 20–32; it hit 27. AIFS led (off 0.6°C); AIGFS ran 1°C cool.
  • Fri Sep 25 14 days out the models said 22–27; it hit 29. GFS led (off 0.4°C); UKMO ran 2°C cool.
  • Thu Sep 24 14 days out the models said 20–31; it hit 27. GFS led (off 0.1°C); GEM ran 3°C cool.
  • Wed Sep 23 14 days out the models said 23–27; it hit 24. UKMO led (off 0.2°C); AIGFS ran 1°C cool.
  • Tue Sep 22 14 days out the models said 18–29; it hit 24. GFS led (off 0.3°C); AIFS ran 5°C cool.
  • Mon Sep 21 14 days out the models said 23–27; it hit 26. UKMO led (off 0.1°C); AIGFS ran 2°C cool.
  • Sun Sep 20 14 days out the models said 22–30; it hit 22. ICON led (off 0.1°C); AIGFS ran 2°C cool.
  • Sat Sep 19 14 days out the models said 29–31; it hit 21. ICON led (off 0.1°C); GEM ran 2°C cool.
  • Fri Sep 18 14 days out the models said 24–33; it hit 28. GFS led (off 0.9°C); ECMWF ran 7°C cool.
  • Thu Sep 17 14 days out the models said 14–33; it hit 30. ECMWF led (off 1.3°C); UKMO ran 3°C cool.
  • Wed Sep 16 14 days out the models said 14–31; it hit 32. GFS led (off 1.1°C); ECMWF ran 4°C cool.
  • Tue Sep 15 14 days out the models said 21–34; it hit 26. ICON led (off 0.1°C); GFS ran 2°C warm.
  • Mon Sep 14 14 days out the models said 16–29; it hit 22. ECMWF led (off 0.0°C); AIGFS ran 2°C cool.
  • Sun Sep 13 14 days out the models said 20–30; it hit 34. GFS led (off 0.5°C); GEM ran 5°C cool.
  • Sat Sep 12 14 days out the models said 25–32; it hit 33. AIFS led (off 0.5°C); AIGFS ran 2°C cool.
  • Fri Sep 11 14 days out the models said 25–32; it hit 32. AIFS led (off 0.9°C); UKMO ran 3°C cool.
  • Thu Sep 10 14 days out the models said 27–34; it hit 32. ECMWF led (off 0.9°C); AIGFS ran 2°C cool.
  • Wed Sep 9 14 days out the models said 21–31; it hit 29. ECMWF led (off 0.4°C); AIGFS ran 3°C cool.
  • Tue Sep 8 14 days out the models said 31–34; it hit 28. AIFS led (off 0.9°C); AIGFS ran 3°C cool.
  • Mon Sep 7 14 days out the models said 27–33; it hit 25. AIFS led (off 0.6°C); AIGFS ran 2°C cool.
  • Sun Sep 6 14 days out the models said 15–29; it hit 32. GEM led (off 0.3°C); UKMO ran 4°C cool.
  • Sat Sep 5 14 days out the models said 26–32; it hit 33. GFS led (off 0.8°C); GEM ran 2°C cool.
  • Fri Sep 4 14 days out the models said 27–36; it hit 32. AIGFS led (off 0.1°C); ECMWF ran 2°C cool.
  • Thu Sep 3 14 days out the models said 31–35; it hit 31. GFS led (off 0.4°C); UKMO ran 2°C cool.
  • Wed Sep 2 13 days out the models said 26–35; it hit 31. GFS led (off 0.3°C); AIFS ran 3°C cool.
  • Tue Sep 1 12 days out the models said 29–32; it hit 29. ICON led (off 0.4°C); AIFS ran 3°C cool.
  • Mon Aug 31 11 days out the models said 26–36; it hit 31. GEM led (off 0.5°C); AIFS ran 6°C cool.
  • Sun Aug 30 10 days out the models said 25–36; it hit 28. GFS led (off 0.5°C); ECMWF ran 5°C cool.
  • Sat Aug 29 9 days out the models said 26–36; it hit 24. AIGFS led (off 0.7°C); GEM ran 4°C cool.
  • Fri Aug 28 8 days out the models said 29–37; it hit 33. GEM led (off 0.2°C); UKMO ran 5°C cool.
  • Thu Aug 27 7 days out the models said 32–36; it hit 36. GEM led (off 0.7°C); AIFS ran 3°C cool.
  • Wed Aug 26 6 days out the models said 33–37; it hit 36. GEM led (off 0.6°C); AIFS ran 2°C cool.
  • Tue Aug 25 5 days out the models said 31–35; it hit 34. ECMWF led (off 0.5°C); ICON ran 2°C cool.
  • Mon Aug 24 4 days out the models said 31–35; it hit 35. ICON led (off 0.4°C); AIFS ran 4°C cool.
  • Sun Aug 23 3 days out the models said 33–35; it hit 34. UKMO led (off 0.6°C); ECMWF ran 2°C cool.
  • Tue Aug 18 14 days out the models said 25–35; it hit 35. ECMWF led (off 0.2°C); AIGFS ran 2°C cool.
  • Mon Aug 17 14 days out the models said 26–36; it hit 35. GFS led (off 0.6°C); UKMO ran 2°C cool.
  • Sun Aug 16 14 days out the models said 25–32; it hit 33. GEM led (off 0.3°C); ECMWF ran 3°C cool.
  • Sat Aug 15 14 days out the models said 27–36; it hit 28. AIFS led (off 0.2°C); GFS ran 2°C warm.
  • Fri Aug 14 14 days out the models said 27–41; it hit 25. ICON led (off 0.4°C); GFS ran 3°C warm.
  • Thu Aug 13 14 days out the models said 26–36; it hit 24. ICON led (off 0.4°C); GFS ran 3°C warm.
  • Wed Aug 12 14 days out the models said 29–39; it hit 31. GFS led (off 0.4°C); AIFS ran 4°C cool.
  • Tue Aug 11 14 days out the models said 28–36; it hit 36. GFS led (off 0.3°C); AIFS ran 3°C cool.
  • Mon Aug 10 14 days out the models said 34–37; it hit 36. ICON led (off 0.2°C); AIFS ran 2°C cool.
  • Sun Aug 9 14 days out the models said 34–38; it hit 38. GEM led (off 0.0°C); AIFS ran 3°C cool.
  • Sat Aug 8 14 days out the models said 33–40; it hit 39. GFS led (off 0.4°C); AIFS ran 3°C cool.
  • Fri Aug 7 14 days out the models said 29–39; it hit 40. ECMWF led (off 0.0°C); GEM ran 2°C cool.
  • Thu Aug 6 14 days out the models said 32–38; it hit 39. GFS led (off 0.4°C); GEM ran 2°C cool.
  • Wed Aug 5 14 days out the models said 32–41; it hit 35. GFS led (off 0.1°C); AIGFS ran 2°C cool.
  • Tue Aug 4 14 days out the models said 37–40; it hit 33. ECMWF led (off 0.2°C); AIGFS ran 2°C cool.
  • Mon Aug 3 14 days out the models said 29–40; it hit 33. GFS led (off 0.1°C); ICON ran 2°C cool.
  • Sun Aug 2 14 days out the models said 37–38; it hit 38. GFS led (off 0.0°C); AIGFS ran 2°C cool.
  • Sat Aug 1 14 days out the models said 34–39; it hit 40. ECMWF led (off 0.1°C); GEM ran 2°C cool.
  • Fri Jul 31 14 days out the models said 35–39; it hit 39. ECMWF led (off 0.2°C); GEM ran 2°C cool.
  • Thu Jul 30 13 days out the models said 34–38; it hit 35. GEM led (off 0.0°C); GFS ran 2°C warm.
  • Wed Jul 29 12 days out the models said 34–39; it hit 34. ICON led (off 0.0°C); AIFS ran 3°C cool.
  • Tue Jul 28 11 days out the models said 31–38; it hit 35. UKMO led (off 0.2°C); GEM ran 2°C warm.
  • Mon Jul 27 10 days out the models said 33–38; it hit 36. ICON led (off 0.4°C); GFS ran 3°C warm.
  • Sun Jul 26 9 days out the models said 31–37; it hit 39. ECMWF led (off 0.0°C); GFS ran 2°C warm.
  • Sat Jul 25 8 days out the models said 27–35; it hit 39. GFS led (off 0.1°C); AIGFS ran 2°C cool.
  • Fri Jul 24 7 days out the models said 28–38; it hit 37. ECMWF led (off 0.4°C); GFS ran 2°C warm.
  • Thu Jul 23 6 days out the models said 24–36; it hit 36. GFS led (off 0.0°C); ECMWF ran 3°C cool.
  • Wed Jul 22 5 days out the models said 28–37; it hit 31. ICON led (off 0.4°C); GEM ran 2°C warm.
  • Tue Jul 21 4 days out the models said 32–36; it hit 37. UKMO led (off 0.5°C); AIGFS ran 4°C cool.
  • Mon Jul 20 3 days out the models said 36–39; it hit 39. GFS led (off 0.4°C); AIFS ran 3°C cool.

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