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Which weather model is most accurate in San Francisco?

Forecast Highs Lows Rain Model accuracy

San Francisco, California · daily high temperature in °C · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for San Francisco at 1-, 3-, and 7-day leads, then scores those forecasts against the SFOC1 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, ECMWF IFS has been most accurate (typical miss 1.24°C); at three days, too close to call; at seven days, ECMWF AIFS (AI) (2.45°C).

The largest standing bias belongs to NOAA AIGFS (AI), which has run warm by about 2.36°C at 1-day lead over this window.

San Francisco'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
ECMWF IFS 1.2° (-0.2°) 1.5° (-0.7°) 3.6° (-3.0°) 29
ECMWF AIFS (AI) 1.5° (+0.6°) 1.5° (+0.8°) 2.5° (-0.4°) 29
UKMO (UK) 1.7° (+0.8°) 2.0° (+1.0°) — 29
NOAA GFS 1.7° (+1.1°) 2.5° (+1.4°) 3.6° (+1.3°) 29
GEM (Canada) 2.0° (-1.1°) 2.2° (-1.0°) 2.9° (-1.4°) 29
DWD ICON 2.3° (-2.0°) 1.7° (-1.1°) — 29
NOAA AIGFS (AI) 2.5° (+2.4°) 2.7° (+2.3°) 3.2° (+1.7°) 29

Method, honestly

The Spread's San Francisco point is the Duboce Triangle station (SFOC1), 0.6 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 Duboce Triangle (SFOC1) — 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 22–33; it hit 31. AIGFS led (off 0.4°C); GEM ran 7°C cool.
  • Thu Oct 15 14 days out the models said 17–26; it hit 28. UKMO led (off 0.1°C); GEM ran 4°C cool.
  • Wed Oct 14 14 days out the models said 17–23; it hit 22. ECMWF led (off 0.4°C); ICON ran 3°C cool.
  • Tue Oct 13 14 days out the models said 19–25; it hit 23. AIGFS led (off 0.1°C); GEM ran 5°C cool.
  • Mon Oct 12 14 days out the models said 16–26; it hit 19. GFS led (off 0.1°C); GEM ran 2°C cool.
  • Sun Oct 11 14 days out the models said 21–33; it hit 17. ECMWF led (off 0.1°C); GEM ran 1°C cool.
  • Sat Oct 10 14 days out the models said 22–29; it hit 17. AIGFS led (off 0.2°C); ICON ran 1°C cool.
  • Fri Oct 9 14 days out the models said 22–31; it hit 18. AIFS led (off 0.4°C); GFS ran 4°C warm.
  • Thu Oct 8 14 days out the models said 19–33; it hit 24. GFS led (off 0.0°C); ICON ran 8°C cool.
  • Wed Oct 7 14 days out the models said 19–32; it hit 22. ECMWF led (off 0.9°C); AIGFS ran 6°C warm.
  • Tue Oct 6 13 days out the models said 18–27; it hit 22. ICON led (off 0.1°C); AIGFS ran 8°C warm.
  • Mon Oct 5 14 days out the models said 20–30; it hit 22. ICON led (off 1.1°C); AIGFS ran 8°C warm.
  • Sun Oct 4 14 days out the models said 17–28; it hit 30. AIGFS led (off 0.1°C); ICON ran 6°C cool.
  • Sat Oct 3 14 days out the models said 20–33; it hit 33. AIGFS led (off 0.7°C); ICON ran 6°C cool.
  • Fri Oct 2 14 days out the models said 18–32; it hit 24. AIFS led (off 0.3°C); ICON ran 4°C cool.
  • Thu Oct 1 14 days out the models said 20–21; it hit 20. UKMO led (off 0.2°C); GFS ran 5°C warm.
  • Wed Sep 30 14 days out the models said 18–29; it hit 22. GEM led (off 0.3°C); AIGFS ran 6°C warm.
  • Tue Sep 29 14 days out the models said 17–24; it hit 23. AIFS led (off 0.5°C); AIGFS ran 3°C warm.
  • Mon Sep 28 14 days out the models said 17–32; it hit 21. AIGFS led (off 0.3°C); ICON ran 3°C cool.
  • Sun Sep 27 14 days out the models said 20–30; it hit 17. ECMWF led (off 0.0°C); UKMO ran 3°C warm.
  • Sat Sep 26 13 days out the models said 18–26; it hit 20. AIGFS led (off 0.7°C); ICON ran 3°C cool.
  • Fri Sep 25 14 days out the models said 20–24; it hit 19. GFS led (off 0.0°C); UKMO ran 5°C warm.
  • Thu Sep 24 14 days out the models said 19–29; it hit 24. AIFS led (off 0.8°C); ICON ran 6°C cool.
  • Wed Sep 23 14 days out the models said 21–29; it hit 24. GFS led (off 0.8°C); ICON ran 3°C cool.
  • Tue Sep 22 14 days out the models said 19–24; it hit 17. ICON led (off 0.1°C); GFS ran 3°C warm.
  • Mon Sep 21 14 days out the models said 18–28; it hit 16. UKMO led (off 0.2°C); AIGFS ran 3°C warm.
  • Sun Sep 20 14 days out the models said 20–30; it hit 16. UKMO led (off 0.4°C); AIGFS ran 4°C warm.
  • Sat Sep 19 14 days out the models said 17–21; it hit 19. ICON led (off 0.1°C); AIGFS ran 4°C warm.
  • Fri Sep 18 13 days out the models said 18–21; it hit 19. ECMWF led (off 0.1°C); AIGFS ran 4°C warm.
  • Thu Sep 17 14 days out the models said 18–30; it hit 21. GFS led (off 0.1°C); GEM ran 2°C cool.
  • Wed Sep 16 14 days out the models said 20–30; it hit 17. UKMO led (off 0.0°C); AIGFS ran 1°C warm.
  • Tue Sep 15 14 days out the models said 20–25; it hit 19. GEM led (off 0.4°C); GFS ran 3°C warm.
  • Mon Sep 14 14 days out the models said 18–35; it hit 22. ECMWF led (off 0.9°C); AIGFS ran 2°C warm.
  • Sun Sep 13 14 days out the models said 19–26; it hit 19. GFS led (off 0.4°C); UKMO ran 3°C warm.
  • Sat Sep 12 14 days out the models said 19–23; it hit 20. AIFS led (off 0.2°C); GEM ran 2°C cool.
  • Fri Sep 11 14 days out the models said 19–27; it hit 19. UKMO led (off 0.2°C); AIGFS ran 4°C warm.
  • Thu Sep 10 14 days out the models said 17–29; it hit 24. UKMO led (off 1.1°C); AIGFS ran 4°C warm.
  • Wed Sep 9 14 days out the models said 17–25; it hit 34. AIGFS led (off 0.3°C); GEM ran 6°C cool.
  • Tue Sep 8 14 days out the models said 18–21; it hit 29. AIFS led (off 0.2°C); ICON ran 6°C cool.
  • Mon Sep 7 14 days out the models said 17–23; it hit 27. AIGFS led (off 0.7°C); ICON ran 4°C cool.
  • Sun Sep 6 14 days out the models said 19–27; it hit 21. UKMO led (off 0.1°C); GEM ran 3°C cool.
  • Sat Sep 5 14 days out the models said 18–25; it hit 22. AIGFS led (off 0.2°C); ICON ran 4°C cool.
  • Fri Sep 4 13 days out the models said 19–24; it hit 20. AIFS led (off 0.2°C); GEM ran 2°C cool.
  • Thu Sep 3 12 days out the models said 19–22; it hit 22. GFS led (off 0.3°C); ICON ran 4°C cool.
  • Wed Sep 2 11 days out the models said 19–23; it hit 21. ECMWF led (off 0.2°C); ICON ran 2°C cool.
  • Tue Sep 1 10 days out the models said 18–22; it hit 21. GFS led (off 0.5°C); GEM ran 2°C cool.
  • Mon Aug 31 9 days out the models said 16–20; it hit 18. AIGFS led (off 0.0°C); GEM ran 2°C cool.
  • Sun Aug 30 8 days out the models said 17–21; it hit 18. ECMWF led (off 0.3°C); AIFS ran 2°C warm.
  • Sat Aug 29 7 days out the models said 15–23; it hit 19. GFS led (off 0.1°C); UKMO ran 3°C warm.
  • Fri Aug 28 6 days out the models said 16–24; it hit 20. AIFS led (off 0.5°C); AIGFS ran 3°C warm.
  • Thu Aug 27 5 days out the models said 20–26; it hit 21. ECMWF led (off 0.5°C); AIGFS ran 4°C warm.
  • Wed Aug 26 4 days out the models said 18–25; it hit 21. ICON led (off 0.4°C); AIGFS ran 6°C warm.
  • Tue Aug 25 3 days out the models said 18–23; it hit 21. GFS led (off 0.6°C); ICON ran 3°C cool.
  • Wed Aug 19 14 days out the models said 18–22; it hit 18. ICON led (off 0.6°C); AIGFS ran 6°C warm.
  • Tue Aug 18 14 days out the models said 18–23; it hit 18. GEM led (off 0.4°C); AIGFS ran 5°C warm.
  • Mon Aug 17 14 days out the models said 18–20; it hit 19. ECMWF led (off 0.1°C); AIGFS ran 4°C warm.
  • Sun Aug 16 14 days out the models said 18–23; it hit 18. GEM led (off 0.3°C); AIGFS ran 4°C warm.
  • Sat Aug 15 14 days out the models said 16–22; it hit 18. ECMWF led (off 0.3°C); AIGFS ran 2°C warm.
  • Fri Aug 14 14 days out the models said 18–24; it hit 18. AIFS led (off 0.0°C); AIGFS ran 1°C warm.
  • Thu Aug 13 14 days out the models said 17–23; it hit 19. GEM led (off 0.1°C); AIGFS ran 2°C warm.
  • Wed Aug 12 14 days out the models said 19–25; it hit 19. GEM led (off 0.4°C); AIGFS ran 3°C warm.
  • Tue Aug 11 14 days out the models said 17–22; it hit 18. ICON led (off 0.8°C); AIGFS ran 4°C warm.
  • Mon Aug 10 14 days out the models said 20–22; it hit 19. UKMO led (off 0.1°C); AIGFS ran 4°C warm.
  • Sun Aug 9 14 days out the models said 17–23; it hit 19. ICON led (off 1.1°C); AIGFS ran 10°C warm.
  • Sat Aug 8 13 days out the models said 18–24; it hit 16. ICON led (off 0.1°C); AIGFS ran 9°C warm.
  • Fri Aug 7 12 days out the models said 17–28; it hit 17. ICON led (off 0.8°C); AIGFS ran 8°C warm.
  • Thu Aug 6 11 days out the models said 19–28; it hit 18. ICON led (off 0.2°C); AIGFS ran 6°C warm.
  • Wed Aug 5 10 days out the models said 20–30; it hit 19. GFS led (off 0.1°C); AIGFS ran 6°C warm.
  • Tue Aug 4 9 days out the models said 19–29; it hit 20. ECMWF led (off 0.9°C); AIGFS ran 6°C warm.
  • Mon Aug 3 8 days out the models said 18–25; it hit 21. ICON led (off 1.3°C); GFS ran 8°C warm.
  • Sun Aug 2 7 days out the models said 19–27; it hit 22. GEM led (off 0.2°C); GFS ran 6°C warm.
  • Sat Aug 1 6 days out the models said 20–27; it hit 22. ECMWF led (off 0.7°C); AIGFS ran 6°C warm.
  • Fri Jul 31 5 days out the models said 18–26; it hit 20. ECMWF led (off 0.2°C); ICON ran 3°C cool.
  • Thu Jul 30 4 days out the models said 18–25; it hit 18. GEM led (off 0.2°C); AIGFS ran 5°C warm.

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