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Which weather model is most accurate in Denver?

Forecast Highs Lows Rain Model accuracy

Denver, Colorado · daily high temperature in °C · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for Denver at 1-, 3-, and 7-day leads, then scores those forecasts against the DEN 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 NOAA AIGFS (AI), which has run cool by about 2.51°C at 3-day lead over this window.

Denver'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
DWD ICON 1.1° (-0.9°) 2.1° (-1.5°) — 29
ECMWF IFS 1.1° (-0.3°) 1.8° (-0.7°) 2.9° (-2.1°) 29
NOAA GFS 1.2° (-0.2°) 1.6° (-0.7°) 3.1° (+0.5°) 29
GEM (Canada) 1.3° (-0.6°) 1.9° (-1.2°) 3.2° (-1.3°) 29
UKMO (UK) 1.3° (-0.4°) 1.8° (-0.8°) — 29
ECMWF AIFS (AI) 1.5° (-1.2°) 2.4° (-2.1°) 3.1° (-1.7°) 29
NOAA AIGFS (AI) 2.2° (-1.9°) 2.6° (-2.5°) 4.2° (-3.1°) 29

Method, honestly

The Spread's Denver point is the Denver International station (DEN), 29 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 Denver International (DEN) — 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 15–17; it hit 14. GFS led (off 0.0°C); AIGFS ran 3°C cool.
  • Thu Oct 15 14 days out the models said 15–26; it hit 12. ECMWF led (off 0.1°C); AIGFS ran 3°C cool.
  • Wed Oct 14 14 days out the models said 4–26; it hit 9. ICON led (off 1.0°C); UKMO ran 3°C warm.
  • Tue Oct 13 14 days out the models said 23–26; it hit 19. GFS led (off 0.1°C); AIGFS ran 5°C cool.
  • Mon Oct 12 14 days out the models said 19–28; it hit 28. ECMWF led (off 0.2°C); AIGFS ran 3°C cool.
  • Sun Oct 11 14 days out the models said 22–25; it hit 29. UKMO led (off 0.3°C); AIGFS ran 5°C cool.
  • Sat Oct 10 14 days out the models said 21–27; it hit 28. ECMWF led (off 0.0°C); AIGFS ran 2°C cool.
  • Fri Oct 9 14 days out the models said 22–30; it hit 30. AIFS led (off 0.1°C); AIGFS ran 2°C cool.
  • Thu Oct 8 14 days out the models said 23–25; it hit 29. UKMO led (off 0.2°C); AIGFS ran 1°C cool.
  • Wed Oct 7 14 days out the models said 15–25; it hit 27. ICON led (off 0.2°C); GEM ran 2°C warm.
  • Tue Oct 6 13 days out the models said 21–28; it hit 31. AIFS led (off 0.1°C); AIGFS ran 3°C cool.
  • Mon Oct 5 14 days out the models said 18–29; it hit 31. ECMWF led (off 0.0°C); AIGFS ran 2°C cool.
  • Sun Oct 4 14 days out the models said 20–26; it hit 27. AIFS led (off 0.1°C); AIGFS ran 1°C cool.
  • Sat Oct 3 14 days out the models said 20–27; it hit 28. AIFS led (off 0.1°C); GEM ran 1°C cool.
  • Fri Oct 2 14 days out the models said 19–27; it hit 27. ECMWF led (off 0.1°C); AIGFS ran 2°C cool.
  • Thu Oct 1 14 days out the models said 9–26; it hit 21. GFS led (off 0.1°C); AIFS ran 2°C cool.
  • Wed Sep 30 14 days out the models said 15–26; it hit 18. GEM led (off 0.4°C); UKMO ran 3°C warm.
  • Tue Sep 29 14 days out the models said 24–31; it hit 22. GFS led (off 1.0°C); GEM ran 3°C cool.
  • Mon Sep 28 14 days out the models said 22–29; it hit 22. UKMO led (off 0.2°C); GFS ran 4°C warm.
  • Sun Sep 27 14 days out the models said 16–26; it hit 28. GFS led (off 0.4°C); UKMO ran 2°C cool.
  • Sat Sep 26 14 days out the models said 26–27; it hit 27. GFS led (off 0.2°C); GEM ran 2°C cool.
  • Fri Sep 25 14 days out the models said 20–28; it hit 24. UKMO led (off 0.0°C); AIFS ran 4°C cool.
  • Thu Sep 24 14 days out the models said 19–31; it hit 22. AIFS led (off 0.4°C); ECMWF ran 3°C warm.
  • Wed Sep 23 14 days out the models said 19–24; it hit 22. AIFS led (off 0.1°C); GEM ran 2°C warm.
  • Tue Sep 22 14 days out the models said 23–31; it hit 28. GEM led (off 0.2°C); AIGFS ran 4°C cool.
  • Mon Sep 21 14 days out the models said 19–29; it hit 24. GEM led (off 0.3°C); AIGFS ran 2°C cool.
  • Sun Sep 20 14 days out the models said 25–28; it hit 23. GFS led (off 0.1°C); UKMO ran 4°C cool.
  • Sat Sep 19 14 days out the models said 18–30; it hit 25. GEM led (off 0.2°C); ECMWF ran 3°C cool.
  • Fri Sep 18 14 days out the models said 26–31; it hit 30. UKMO led (off 1.6°C); AIGFS ran 4°C cool.
  • Thu Sep 17 14 days out the models said 21–29; it hit 29. GEM led (off 0.0°C); UKMO ran 5°C cool.
  • Wed Sep 16 14 days out the models said 28–30; it hit 28. GFS led (off 0.3°C); ICON ran 2°C cool.
  • Tue Sep 15 14 days out the models said 27–32; it hit 22. AIFS led (off 0.2°C); GFS ran 4°C warm.
  • Mon Sep 14 14 days out the models said 23–30; it hit 31. ECMWF led (off 0.2°C); AIGFS ran 1°C cool.
  • Sun Sep 13 14 days out the models said 24–34; it hit 34. ECMWF led (off 0.1°C); GEM ran 3°C cool.
  • Sat Sep 12 14 days out the models said 27–34; it hit 26. AIFS led (off 0.0°C); UKMO ran 6°C warm.
  • Fri Sep 11 14 days out the models said 22–32; it hit 32. GFS led (off 0.1°C); UKMO ran 1°C warm.
  • Thu Sep 10 14 days out the models said 25–32; it hit 32. UKMO led (off 0.2°C); AIGFS ran 2°C cool.
  • Wed Sep 9 14 days out the models said 25–32; it hit 28. ECMWF led (off 0.3°C); AIGFS ran 2°C cool.
  • Tue Sep 8 14 days out the models said 26–32; it hit 30. UKMO led (off 0.2°C); AIGFS ran 2°C cool.
  • Mon Sep 7 14 days out the models said 20–31; it hit 32. ECMWF led (off 0.6°C); AIGFS ran 3°C cool.
  • Sun Sep 6 13 days out the models said 15–29; it hit 33. ECMWF led (off 0.3°C); AIFS ran 3°C cool.
  • Sat Sep 5 12 days out the models said 23–30; it hit 34. ECMWF led (off 1.3°C); GFS ran 3°C cool.
  • Fri Sep 4 11 days out the models said 21–32; it hit 34. UKMO led (off 0.1°C); AIGFS ran 2°C cool.
  • Thu Sep 3 10 days out the models said 27–31; it hit 33. AIFS led (off 0.4°C); AIGFS ran 2°C cool.
  • Wed Sep 2 9 days out the models said 27–30; it hit 31. AIFS led (off 0.0°C); ICON ran 2°C cool.
  • Tue Sep 1 8 days out the models said 27–31; it hit 31. GEM led (off 1.2°C); AIGFS ran 3°C cool.
  • Mon Aug 31 7 days out the models said 25–30; it hit 30. GFS led (off 0.4°C); ICON ran 4°C cool.
  • Sun Aug 30 6 days out the models said 26–32; it hit 29. GFS led (off 0.6°C); UKMO ran 3°C warm.
  • Sat Aug 29 5 days out the models said 31–36; it hit 34. ICON led (off 0.7°C); AIFS ran 2°C cool.
  • Fri Aug 28 4 days out the models said 33–34; it hit 35. ECMWF led (off 0.9°C); UKMO ran 2°C cool.
  • Wed Aug 19 14 days out the models said 27–32; it hit 33. GFS led (off 0.2°C); GEM ran 3°C cool.
  • Tue Aug 18 14 days out the models said 22–37; it hit 32. UKMO led (off 0.2°C); ICON ran 3°C warm.
  • Mon Aug 17 14 days out the models said 26–38; it hit 35. GFS led (off 0.4°C); GEM ran 4°C cool.
  • Sun Aug 16 14 days out the models said 25–32; it hit 29. GFS led (off 0.7°C); GEM ran 3°C cool.
  • Sat Aug 15 14 days out the models said 24–32; it hit 27. ECMWF led (off 0.1°C); GEM ran 3°C cool.
  • Fri Aug 14 14 days out the models said 22–36; it hit 30. UKMO led (off 0.3°C); GEM ran 5°C cool.
  • Thu Aug 13 14 days out the models said 27–36; it hit 27. ECMWF led (off 0.0°C); GFS ran 3°C warm.
  • Wed Aug 12 14 days out the models said 23–37; it hit 34. ECMWF led (off 0.3°C); AIFS ran 3°C cool.
  • Tue Aug 11 14 days out the models said 33–39; it hit 36. GFS led (off 0.3°C); GEM ran 2°C cool.
  • Mon Aug 10 14 days out the models said 32–33; it hit 34. AIFS led (off 0.1°C); UKMO ran 2°C warm.
  • Sun Aug 9 14 days out the models said 28–37; it hit 36. ICON led (off 0.1°C); GEM ran 2°C cool.
  • Sat Aug 8 14 days out the models said 34–39; it hit 38. ECMWF led (off 0.1°C); GEM ran 3°C cool.
  • Fri Aug 7 13 days out the models said 35–40; it hit 36. UKMO led (off 0.4°C); GEM ran 4°C cool.
  • Thu Aug 6 12 days out the models said 32–38; it hit 37. ECMWF led (off 0.3°C); GEM ran 6°C cool.
  • Wed Aug 5 11 days out the models said 28–39; it hit 29. ICON led (off 0.0°C); GFS ran 1°C warm.
  • Tue Aug 4 10 days out the models said 24–39; it hit 24. AIFS led (off 0.3°C); ECMWF ran 2°C warm.
  • Mon Aug 3 9 days out the models said 27–34; it hit 39. ICON led (off 0.2°C); GEM ran 6°C cool.
  • Sun Aug 2 8 days out the models said 34–40; it hit 39. ECMWF led (off 0.1°C); GEM ran 4°C cool.
  • Sat Aug 1 7 days out the models said 33–39; it hit 35. ICON led (off 0.2°C); GEM ran 4°C cool.
  • Fri Jul 31 6 days out the models said 32–39; it hit 32. ICON led (off 0.1°C); ECMWF ran 2°C cool.
  • Thu Jul 30 5 days out the models said 32–38; it hit 35. GFS led (off 0.3°C); ECMWF ran 5°C cool.
  • Wed Jul 29 4 days out the models said 30–36; it hit 33. AIFS led (off 1.7°C); ECMWF ran 4°C cool.
  • Tue Jul 28 3 days out the models said 29–38; it hit 33. ECMWF led (off 0.3°C); AIGFS ran 3°C cool.

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