The Spread Maps Request an invite

Which weather model is most accurate in Seattle?

Forecast Highs Lows Rain Model accuracy

Seattle, Washington · daily high temperature in °F · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for Seattle at 1-, 3-, and 7-day leads, then scores those forecasts against the SEA 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, ECMWF AIFS (AI) (3.18°F).

The largest standing bias belongs to NOAA GFS, which has run warm by about 2.75°F at 1-day lead over this window.

Seattle'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
UKMO (UK) 2.1° (-0.1°) 2.5° (+0.1°) — 29
DWD ICON 2.3° (-1.8°) 2.6° (-0.9°) 3.9° (-1.0°) 29
GEM (Canada) 2.5° (+1.6°) 2.5° (+0.5°) 3.8° (-0.3°) 29
NOAA AIGFS (AI) 2.5° (-0.5°) 3.3° (-1.1°) 5.2° (-1.9°) 29
ECMWF IFS 2.6° (-2.2°) 3.1° (-2.4°) 4.5° (-3.2°) 29
ECMWF AIFS (AI) 2.9° (-2.7°) 2.7° (-2.4°) 3.2° (-2.3°) 29
NOAA GFS 3.7° (+2.8°) 4.2° (+1.4°) 4.9° (+2.1°) 29

Method, honestly

The Spread's Seattle point is the Sea-Tac station (SEA), 11 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 Sea-Tac (SEA) — 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 60–68; it hit 77. GFS led (off 2.7°F); AIFS ran 9°F cool.
  • Thu Oct 15 14 days out the models said 56–58; it hit 68. UKMO led (off 0.3°F); GEM ran 7°F warm.
  • Wed Oct 14 14 days out the models said 56–64; it hit 67. GEM led (off 1.1°F); AIGFS ran 4°F cool.
  • Tue Oct 13 14 days out the models said 62–82; it hit 62. GEM led (off 0.1°F); AIGFS ran 4°F cool.
  • Mon Oct 12 14 days out the models said 58–72; it hit 61. GEM led (off 0.2°F).
  • Sun Oct 11 14 days out the models said 63–79; it hit 60. GEM led (off 0.2°F); AIGFS ran 3°F cool.
  • Sat Oct 10 14 days out the models said 56–81; it hit 58. GEM led (off 0.2°F); AIGFS ran 4°F cool.
  • Fri Oct 9 14 days out the models said 61–80; it hit 58. AIFS led (off 0.0°F); GFS ran 6°F warm.
  • Thu Oct 8 14 days out the models said 68–77; it hit 67. ICON led (off 0.2°F); GFS ran 6°F warm.
  • Wed Oct 7 14 days out the models said 66–80; it hit 67. AIGFS led (off 0.5°F); GFS ran 4°F warm.
  • Tue Oct 6 14 days out the models said 58–70; it hit 66. GEM led (off 1.2°F); ECMWF ran 5°F cool.
  • Mon Oct 5 14 days out the models said 66–74; it hit 68. UKMO led (off 0.2°F); ICON ran 5°F cool.
  • Sun Oct 4 14 days out the models said 54–64; it hit 69. ICON led (off 0.2°F); GFS ran 7°F warm.
  • Sat Oct 3 14 days out the models said 62–75; it hit 67. ICON led (off 0.4°F); GFS ran 6°F warm.
  • Fri Oct 2 14 days out the models said 61–71; it hit 71. UKMO led (off 0.9°F); AIFS ran 3°F cool.
  • Thu Oct 1 14 days out the models said 59–69; it hit 68. AIGFS led (off 0.8°F); ICON ran 7°F cool.
  • Wed Sep 30 14 days out the models said 61–77; it hit 65. UKMO led (off 0.3°F); ECMWF ran 4°F cool.
  • Tue Sep 29 14 days out the models said 60–68; it hit 63. ECMWF led (off 0.0°F); AIGFS ran 5°F cool.
  • Mon Sep 28 14 days out the models said 55–67; it hit 64. ECMWF led (off 0.1°F); UKMO ran 4°F warm.
  • Sun Sep 27 14 days out the models said 62–75; it hit 65. UKMO led (off 0.1°F); ECMWF ran 3°F cool.
  • Sat Sep 26 14 days out the models said 61–78; it hit 64. UKMO led (off 0.2°F); ECMWF ran 3°F cool.
  • Fri Sep 25 14 days out the models said 58–70; it hit 62. ICON led (off 0.9°F); AIGFS ran 4°F cool.
  • Thu Sep 24 14 days out the models said 60–74; it hit 63. ICON led (off 0.3°F); AIFS ran 6°F cool.
  • Wed Sep 23 14 days out the models said 60–74; it hit 67. GFS led (off 0.4°F); UKMO ran 5°F cool.
  • Tue Sep 22 14 days out the models said 56–76; it hit 68. GEM led (off 0.1°F); GFS ran 3°F warm.
  • Mon Sep 21 14 days out the models said 60–69; it hit 67. ECMWF led (off 0.8°F); GFS ran 4°F warm.
  • Sun Sep 20 14 days out the models said 64–81; it hit 70. UKMO led (off 1.4°F); GFS ran 6°F warm.
  • Sat Sep 19 14 days out the models said 66–79; it hit 63. AIFS led (off 1.2°F); GFS ran 14°F warm.
  • Fri Sep 18 14 days out the models said 65–69; it hit 69. ECMWF led (off 1.2°F); GFS ran 7°F warm.
  • Thu Sep 17 14 days out the models said 63–77; it hit 77. GEM led (off 0.7°F); ECMWF ran 6°F cool.
  • Wed Sep 16 14 days out the models said 68–72; it hit 74. AIGFS led (off 0.1°F); ECMWF ran 4°F cool.
  • Tue Sep 15 14 days out the models said 65–73; it hit 68. GEM led (off 0.9°F); AIGFS ran 6°F cool.
  • Mon Sep 14 14 days out the models said 68–78; it hit 67. ECMWF led (off 0.7°F); AIFS ran 2°F cool.
  • Sun Sep 13 14 days out the models said 60–72; it hit 60. ECMWF led (off 0.7°F); AIGFS ran 5°F cool.
  • Sat Sep 12 14 days out the models said 66–79; it hit 66. UKMO led (off 0.9°F); GEM ran 4°F warm.
  • Fri Sep 11 14 days out the models said 60–68; it hit 67. ECMWF led (off 0.7°F); GEM ran 3°F warm.
  • Thu Sep 10 14 days out the models said 67–86; it hit 71. GFS led (off 0.7°F); AIFS ran 4°F cool.
  • Wed Sep 9 14 days out the models said 63–85; it hit 78. UKMO led (off 0.9°F); AIFS ran 5°F cool.
  • Tue Sep 8 14 days out the models said 64–88; it hit 74. AIGFS led (off 0.4°F); ECMWF ran 4°F cool.
  • Mon Sep 7 14 days out the models said 80–100; it hit 70. GEM led (off 1.1°F); AIGFS ran 4°F cool.
  • Sun Sep 6 14 days out the models said 63–83; it hit 74. UKMO led (off 0.1°F); AIFS ran 5°F cool.
  • Sat Sep 5 13 days out the models said 58–74; it hit 70. AIGFS led (off 0.0°F); GFS ran 6°F warm.
  • Fri Sep 4 12 days out the models said 58–68; it hit 70. GEM led (off 0.3°F); AIFS ran 4°F cool.
  • Thu Sep 3 11 days out the models said 58–66; it hit 68. GFS led (off 3.5°F); GEM ran 6°F cool.
  • Wed Sep 2 10 days out the models said 65–68; it hit 70. GFS led (off 1.3°F); AIFS ran 7°F cool.
  • Tue Sep 1 9 days out the models said 63–76; it hit 66. AIFS led (off 0.4°F); GFS ran 10°F warm.
  • Mon Aug 31 8 days out the models said 60–78; it hit 76. AIGFS led (off 0.0°F); ICON ran 5°F cool.
  • Sun Aug 30 7 days out the models said 66–73; it hit 71. UKMO led (off 0.1°F); ECMWF ran 5°F cool.
  • Sat Aug 29 6 days out the models said 64–73; it hit 71. UKMO led (off 1.0°F); AIGFS ran 8°F cool.
  • Fri Aug 28 5 days out the models said 67–73; it hit 73. ICON led (off 0.4°F); AIFS ran 5°F cool.
  • Thu Aug 27 4 days out the models said 70–77; it hit 74. GEM led (off 0.4°F); AIFS ran 4°F cool.
  • Wed Aug 26 3 days out the models said 74–82; it hit 77. GEM led (off 0.2°F); GFS ran 7°F warm.
  • Tue Aug 18 14 days out the models said 71–82; it hit 82. GFS led (off 1.4°F); AIFS ran 8°F cool.
  • Mon Aug 17 14 days out the models said 74–85; it hit 78. GFS led (off 0.1°F); AIFS ran 4°F cool.
  • Sun Aug 16 14 days out the models said 75–89; it hit 75. AIGFS led (off 0.1°F); AIFS ran 7°F cool.
  • Sat Aug 15 14 days out the models said 72–82; it hit 77. AIGFS led (off 0.2°F); AIFS ran 8°F cool.
  • Fri Aug 14 14 days out the models said 68–80; it hit 80. GFS led (off 0.1°F); AIFS ran 6°F cool.
  • Thu Aug 13 14 days out the models said 72–81; it hit 80. GFS led (off 0.3°F); AIGFS ran 5°F warm.
  • Wed Aug 12 14 days out the models said 77–92; it hit 76. ECMWF led (off 0.5°F); GEM ran 3°F warm.
  • Tue Aug 11 14 days out the models said 71–84; it hit 77. ECMWF led (off 0.0°F); ICON ran 3°F cool.
  • Mon Aug 10 14 days out the models said 63–79; it hit 75. ICON led (off 0.4°F); AIGFS ran 5°F warm.
  • Sun Aug 9 14 days out the models said 68–81; it hit 76. GFS led (off 1.6°F); AIGFS ran 4°F warm.
  • Sat Aug 8 14 days out the models said 70–81; it hit 82. GEM led (off 0.2°F); AIFS ran 4°F cool.
  • Fri Aug 7 14 days out the models said 73–96; it hit 86. ECMWF led (off 0.6°F); AIFS ran 6°F cool.
  • Thu Aug 6 14 days out the models said 65–92; it hit 85. GFS led (off 0.0°F); AIGFS ran 6°F warm.
  • Wed Aug 5 14 days out the models said 76–87; it hit 84. GFS led (off 0.1°F); AIGFS ran 6°F warm.
  • Tue Aug 4 14 days out the models said 76–87; it hit 79. ICON led (off 0.5°F); AIGFS ran 6°F warm.
  • Mon Aug 3 14 days out the models said 71–84; it hit 74. AIFS led (off 0.0°F); AIGFS ran 4°F warm.
  • Sun Aug 2 14 days out the models said 67–84; it hit 69. ECMWF led (off 0.3°F); AIFS ran 2°F cool.
  • Sat Aug 1 14 days out the models said 72–82; it hit 73. GEM led (off 0.6°F); GFS ran 4°F cool.
  • Fri Jul 31 14 days out the models said 68–81; it hit 82. ECMWF led (off 0.1°F); AIGFS ran 5°F warm.
  • Thu Jul 30 13 days out the models said 70–84; it hit 76. GFS led (off 0.2°F); AIGFS ran 3°F warm.
  • Wed Jul 29 12 days out the models said 74–81; it hit 73. AIFS led (off 0.2°F); GEM ran 4°F warm.
  • Tue Jul 28 11 days out the models said 70–82; it hit 74. ICON led (off 0.6°F); AIFS ran 3°F cool.
  • Mon Jul 27 10 days out the models said 66–83; it hit 78. GEM led (off 0.5°F); ICON ran 4°F cool.
  • Sun Jul 26 9 days out the models said 68–78; it hit 72. UKMO led (off 0.7°F); GEM ran 4°F warm.
  • Sat Jul 25 8 days out the models said 69–80; it hit 71. AIGFS led (off 0.1°F); GEM ran 4°F warm.
  • Fri Jul 24 7 days out the models said 69–84; it hit 79. ICON led (off 0.5°F); GEM ran 4°F warm.
  • Thu Jul 23 6 days out the models said 73–92; it hit 75. GFS led (off 0.6°F); AIFS ran 6°F cool.
  • Wed Jul 22 5 days out the models said 81–94; it hit 88. UKMO led (off 0.2°F); AIGFS ran 6°F warm.
  • Tue Jul 21 4 days out the models said 82–90; it hit 89. ECMWF led (off 0.3°F); ICON ran 5°F cool.
  • Mon Jul 20 3 days out the models said 73–85; it hit 79. AIFS led (off 0.2°F); GFS ran 6°F warm.

Other cities

Atlanta, Georgia Berlin, State of Berlin Boston, Massachusetts Buffalo, New York Charlotte, North Carolina Chicago, Illinois Dallas, Texas Denver, Colorado Detroit, Michigan Houston, Texas London, England Los Angeles, California Miami, Florida Milan, Lombardy Minneapolis, Minnesota New Orleans, Louisiana New York, New York Oklahoma City, Oklahoma Orlando, Florida Paris, Île-de-France Region Philadelphia, Pennsylvania Phoenix, Arizona Salt Lake City, Utah San Antonio, Texas San Diego, California San Francisco, California St. Louis, Missouri Tampa, Florida Washington, District of Columbia

The Spread — the forecast spread — is in closed beta. These verification pages are public while the rest is gated.