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Which weather model is most accurate in San Diego?

Forecast Highs Lows Rain Model accuracy

San Diego, 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 Diego at 1-, 3-, and 7-day leads, then scores those forecasts against the SAN 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, DWD ICON has been most accurate (typical miss 0.99°C); at three days, too close to call; at seven days, ECMWF AIFS (AI) (2.03°C).

The largest standing bias belongs to ECMWF IFS, which has run warm by about 3.26°C at 3-day lead over this window.

San Diego'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 1.0° (+0.6°) 1.3° (+0.8°) — 29
GEM (Canada) 1.2° (-0.1°) 1.4° (-0.2°) 3.2° (+0.7°) 29
ECMWF AIFS (AI) 1.5° (+0.1°) 1.4° (+0.0°) 2.0° (+0.0°) 29
NOAA GFS 1.6° (-0.4°) 1.7° (-0.9°) 2.5° (-1.5°) 29
NOAA AIGFS (AI) 1.7° (+1.0°) 1.5° (+0.5°) 2.8° (-0.2°) 29
UKMO (UK) 2.0° (+1.6°) 1.9° (+1.2°) — 29
ECMWF IFS 3.4° (+3.1°) 3.6° (+3.3°) 3.9° (+1.6°) 29

Method, honestly

The Spread's San Diego point is the Lindbergh Field station (SAN), 2.8 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 Lindbergh Field (SAN) — 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 26–34; it hit 36. AIGFS led (off 0.2°C); AIFS ran 4°C cool.
  • Thu Oct 15 14 days out the models said 22–26; it hit 31. GEM led (off 0.7°C); AIGFS ran 2°C warm.
  • Wed Oct 14 14 days out the models said 19–27; it hit 24. GEM led (off 0.7°C); UKMO ran 2°C warm.
  • Tue Oct 13 14 days out the models said 27–37; it hit 22. ECMWF led (off 0.1°C); AIGFS ran 2°C cool.
  • Mon Oct 12 14 days out the models said 24–38; it hit 22. ICON led (off 0.2°C); AIGFS ran 2°C cool.
  • Sun Oct 11 14 days out the models said 22–36; it hit 23. AIGFS led (off 0.5°C); AIFS ran 2°C cool.
  • Sat Oct 10 14 days out the models said 25–35; it hit 26. ICON led (off 0.0°C); ECMWF ran 4°C warm.
  • Fri Oct 9 14 days out the models said 28–39; it hit 27. ICON led (off 1.2°C); ECMWF ran 5°C warm.
  • Thu Oct 8 14 days out the models said 28–42; it hit 28. GEM led (off 0.8°C); ECMWF ran 6°C warm.
  • Wed Oct 7 14 days out the models said 25–39; it hit 32. GEM led (off 0.3°C); ECMWF ran 5°C warm.
  • Tue Oct 6 13 days out the models said 27–32; it hit 34. ICON led (off 0.4°C); ECMWF ran 5°C warm.
  • Mon Oct 5 14 days out the models said 28–37; it hit 36. ICON led (off 0.3°C); ECMWF ran 4°C warm.
  • Sun Oct 4 14 days out the models said 24–36; it hit 38. UKMO led (off 0.2°C); GFS ran 5°C cool.
  • Sat Oct 3 14 days out the models said 27–37; it hit 41. AIGFS led (off 0.4°C); GEM ran 5°C cool.
  • Fri Oct 2 14 days out the models said 25–42; it hit 35. AIFS led (off 0.9°C); ECMWF ran 6°C warm.
  • Thu Oct 1 14 days out the models said 22–29; it hit 26. GEM led (off 1.6°C); ECMWF ran 7°C warm.
  • Wed Sep 30 14 days out the models said 26–26; it hit 25. ICON led (off 0.2°C); ECMWF ran 5°C warm.
  • Tue Sep 29 14 days out the models said 27–30; it hit 26. GEM led (off 0.2°C); ECMWF ran 4°C warm.
  • Mon Sep 28 14 days out the models said 22–33; it hit 26. ICON led (off 0.3°C); UKMO ran 3°C warm.
  • Sun Sep 27 14 days out the models said 24–37; it hit 27. ICON led (off 0.3°C); AIGFS ran 2°C warm.
  • Sat Sep 26 14 days out the models said 24–34; it hit 27. GFS led (off 1.7°C); ECMWF ran 7°C warm.
  • Fri Sep 25 14 days out the models said 24–31; it hit 26. GEM led (off 0.6°C); ECMWF ran 6°C warm.
  • Thu Sep 24 14 days out the models said 25–27; it hit 25. AIGFS led (off 0.8°C); ECMWF ran 5°C warm.
  • Wed Sep 23 14 days out the models said 27–33; it hit 25. GFS led (off 0.1°C); ECMWF ran 4°C warm.
  • Tue Sep 22 14 days out the models said 23–29; it hit 26. ICON led (off 0.7°C); AIGFS ran 2°C cool.
  • Mon Sep 21 14 days out the models said 25–30; it hit 25. ICON led (off 0.2°C); GFS ran 2°C cool.
  • Sun Sep 20 14 days out the models said 24–33; it hit 25. UKMO led (off 0.0°C); ECMWF ran 2°C warm.
  • Sat Sep 19 14 days out the models said 23–33; it hit 26. ICON led (off 0.1°C); ECMWF ran 3°C warm.
  • Fri Sep 18 14 days out the models said 24–31; it hit 26. GEM led (off 0.3°C); ECMWF ran 2°C warm.
  • Thu Sep 17 14 days out the models said 26–32; it hit 24. GFS led (off 0.2°C); ECMWF ran 2°C warm.
  • Wed Sep 16 14 days out the models said 27–33; it hit 26. UKMO led (off 0.7°C); GFS ran 2°C cool.
  • Tue Sep 15 14 days out the models said 27–31; it hit 24. AIGFS led (off 0.4°C); ECMWF ran 3°C warm.
  • Mon Sep 14 14 days out the models said 23–32; it hit 24. GFS led (off 0.7°C); ECMWF ran 4°C warm.
  • Sun Sep 13 14 days out the models said 27–33; it hit 26. AIGFS led (off 0.5°C); ECMWF ran 3°C warm.
  • Sat Sep 12 14 days out the models said 27–28; it hit 26. GFS led (off 1.2°C); ECMWF ran 5°C warm.
  • Fri Sep 11 14 days out the models said 23–31; it hit 27. ICON led (off 0.8°C); ECMWF ran 5°C warm.
  • Thu Sep 10 14 days out the models said 24–32; it hit 30. ICON led (off 0.4°C); ECMWF ran 6°C warm.
  • Wed Sep 9 14 days out the models said 24–33; it hit 34. ICON led (off 0.9°C); ECMWF ran 6°C warm.
  • Tue Sep 8 14 days out the models said 25–35; it hit 34. AIGFS led (off 0.4°C); ECMWF ran 5°C warm.
  • Mon Sep 7 13 days out the models said 23–32; it hit 35. AIGFS led (off 0.1°C); GFS ran 5°C cool.
  • Sun Sep 6 12 days out the models said 22–32; it hit 35. UKMO led (off 0.2°C); ICON ran 5°C cool.
  • Sat Sep 5 11 days out the models said 23–31; it hit 28. ICON led (off 0.2°C); ECMWF ran 6°C warm.
  • Fri Sep 4 10 days out the models said 24–31; it hit 24. GFS led (off 0.0°C); ECMWF ran 4°C warm.
  • Thu Sep 3 9 days out the models said 25–31; it hit 25. GFS led (off 0.8°C); ECMWF ran 3°C warm.
  • Wed Sep 2 8 days out the models said 25–30; it hit 24. GFS led (off 0.7°C); ECMWF ran 4°C warm.
  • Tue Sep 1 7 days out the models said 25–30; it hit 26. GFS led (off 0.2°C); ECMWF ran 5°C warm.
  • Mon Aug 31 6 days out the models said 26–29; it hit 26. GFS led (off 0.4°C); ECMWF ran 6°C warm.
  • Sun Aug 30 5 days out the models said 26–32; it hit 27. GFS led (off 0.2°C); ECMWF ran 5°C warm.
  • Sat Aug 29 4 days out the models said 28–38; it hit 31. ICON led (off 0.7°C); ECMWF ran 6°C warm.
  • Fri Aug 28 3 days out the models said 30–39; it hit 29. ICON led (off 0.8°C); ECMWF ran 7°C warm.

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