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Which weather model is most accurate in London?

Forecast Highs Lows Rain Model accuracy

London, England · daily high temperature in °F · trailing 30 days, through Fri Oct 16

Every day, The Spread archives what each major weather model predicted for London at 1-, 3-, and 7-day leads, then scores those forecasts against the EGLL 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, GEM (Canada) (4°F).

The largest standing bias belongs to NOAA AIGFS (AI), which has run cool by about 5.7°F at 3-day lead over this window.

London'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
NOAA GFS 2.7° (-2.4°) 3.7° (-3.0°) 5.0° (-4.2°) 29
DWD ICON 3.1° (-3.1°) 3.7° (-3.6°) — 29
UKMO (UK) 3.3° (-3.1°) 4.3° (-3.9°) — 29
ECMWF IFS 3.6° (-3.6°) 3.7° (-3.7°) 5.2° (-5.1°) 29
GEM (Canada) 3.7° (-3.7°) 3.8° (-3.6°) 4.0° (-3.0°) 29
ECMWF AIFS (AI) 4.4° (-4.4°) 5.0° (-5.0°) 4.5° (-4.5°) 29
NOAA AIGFS (AI) 5.2° (-5.2°) 6.0° (-5.7°) 6.2° (-6.2°) 29

Method, honestly

The Spread's London point is the Heathrow station (EGLL), 14 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 Heathrow (EGLL) — 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 52–71; it hit 61. UKMO led (off 0.8°F); AIGFS ran 4°F cool.
  • Thu Oct 15 14 days out the models said 55–63; it hit 73. GFS led (off 1.6°F); AIGFS ran 6°F cool.
  • Wed Oct 14 14 days out the models said 58–64; it hit 69. GFS led (off 2.8°F); ICON ran 5°F cool.
  • Tue Oct 13 14 days out the models said 55–60; it hit 70. GFS led (off 1.1°F); AIGFS ran 4°F cool.
  • Mon Oct 12 14 days out the models said 54–64; it hit 65. GEM led (off 0.2°F); AIGFS ran 4°F cool.
  • Sun Oct 11 14 days out the models said 53–66; it hit 62. GFS led (off 1.1°F); AIFS ran 4°F cool.
  • Sat Oct 10 14 days out the models said 61–78; it hit 61. ICON led (off 2.0°F); GFS ran 5°F cool.
  • Fri Oct 9 14 days out the models said 52–76; it hit 70. GEM led (off 4.4°F); UKMO ran 7°F cool.
  • Thu Oct 8 14 days out the models said 57–71; it hit 60. GFS led (off 1.0°F); GEM ran 5°F cool.
  • Wed Oct 7 14 days out the models said 60–69; it hit 59. ICON led (off 0.3°F); GFS ran 4°F warm.
  • Tue Oct 6 14 days out the models said 62–70; it hit 73. UKMO led (off 2.6°F); AIFS ran 7°F cool.
  • Mon Oct 5 14 days out the models said 59–70; it hit 76. GFS led (off 2.7°F); AIFS ran 8°F cool.
  • Sun Oct 4 14 days out the models said 58–69; it hit 74. GFS led (off 3.7°F); AIGFS ran 9°F cool.
  • Sat Oct 3 14 days out the models said 62–69; it hit 69. GEM led (off 0.3°F); AIGFS ran 3°F cool.
  • Fri Oct 2 14 days out the models said 60–70; it hit 72. GFS led (off 2.3°F); UKMO ran 4°F cool.
  • Thu Oct 1 14 days out the models said 60–69; it hit 71. GFS led (off 1.9°F); AIGFS ran 6°F cool.
  • Wed Sep 30 14 days out the models said 54–73; it hit 77. UKMO led (off 3.1°F); GEM ran 7°F cool.
  • Tue Sep 29 14 days out the models said 56–81; it hit 82. UKMO led (off 3.2°F); AIGFS ran 10°F cool.
  • Mon Sep 28 14 days out the models said 61–74; it hit 69. ICON led (off 2.2°F); AIGFS ran 7°F cool.
  • Sun Sep 27 14 days out the models said 60–71; it hit 72. GFS led (off 0.3°F); AIGFS ran 3°F cool.
  • Sat Sep 26 14 days out the models said 60–73; it hit 73. GFS led (off 4.6°F); AIGFS ran 7°F cool.
  • Fri Sep 25 14 days out the models said 58–73; it hit 77. GFS led (off 2.3°F); AIGFS ran 6°F cool.
  • Thu Sep 24 14 days out the models said 66–77; it hit 72. ECMWF led (off 0.8°F); AIGFS ran 4°F cool.
  • Wed Sep 23 14 days out the models said 61–78; it hit 76. GFS led (off 1.8°F); AIGFS ran 5°F cool.
  • Tue Sep 22 14 days out the models said 64–72; it hit 80. AIFS led (off 5.5°F); AIGFS ran 10°F cool.
  • Mon Sep 21 14 days out the models said 63–68; it hit 76. GFS led (off 3.2°F); GEM ran 8°F cool.
  • Sun Sep 20 14 days out the models said 61–84; it hit 71. GFS led (off 3.4°F); AIFS ran 5°F cool.
  • Sat Sep 19 14 days out the models said 64–78; it hit 75. ECMWF led (off 3.6°F); AIFS ran 7°F cool.
  • Fri Sep 18 13 days out the models said 63–76; it hit 68. GFS led (off 0.6°F); GEM ran 2°F cool.
  • Thu Sep 17 14 days out the models said 59–80; it hit 70. ICON led (off 0.4°F); AIGFS ran 4°F cool.
  • Wed Sep 16 14 days out the models said 55–72; it hit 70. ECMWF led (off 3.0°F); UKMO ran 5°F cool.
  • Tue Sep 15 14 days out the models said 63–81; it hit 73. UKMO led (off 1.5°F); AIGFS ran 4°F cool.
  • Mon Sep 14 14 days out the models said 62–79; it hit 77. GEM led (off 0.4°F); AIFS ran 5°F cool.
  • Sun Sep 13 14 days out the models said 62–75; it hit 73. GEM led (off 0.6°F); AIFS ran 4°F cool.
  • Sat Sep 12 14 days out the models said 62–81; it hit 75. GEM led (off 0.5°F); AIFS ran 4°F cool.
  • Fri Sep 11 14 days out the models said 61–74; it hit 70. AIFS led (off 0.0°F); GFS ran 4°F warm.
  • Thu Sep 10 14 days out the models said 62–84; it hit 66. AIFS led (off 0.4°F); ICON ran 3°F warm.
  • Wed Sep 9 14 days out the models said 62–77; it hit 66. GEM led (off 0.1°F); AIGFS ran 3°F cool.
  • Tue Sep 8 14 days out the models said 63–81; it hit 64. GFS led (off 0.8°F); UKMO ran 6°F warm.
  • Mon Sep 7 14 days out the models said 70–76; it hit 75. GEM led (off 0.3°F); AIFS ran 3°F cool.
  • Sun Sep 6 14 days out the models said 67–73; it hit 81. GFS led (off 1.9°F); AIGFS ran 5°F cool.
  • Sat Sep 5 14 days out the models said 63–76; it hit 73. GFS led (off 1.0°F); AIGFS ran 3°F cool.
  • Fri Sep 4 13 days out the models said 66–69; it hit 70. AIGFS led (off 0.2°F); ECMWF ran 3°F cool.
  • Thu Sep 3 12 days out the models said 66–69; it hit 81. GFS led (off 0.5°F); AIFS ran 8°F cool.
  • Wed Sep 2 11 days out the models said 66–70; it hit 70. UKMO led (off 1.2°F); AIFS ran 3°F cool.
  • Tue Sep 1 10 days out the models said 65–70; it hit 73. GFS led (off 0.3°F); ECMWF ran 5°F cool.
  • Mon Aug 31 9 days out the models said 60–74; it hit 75. GEM led (off 3.1°F); GFS ran 8°F cool.
  • Sun Aug 30 8 days out the models said 67–73; it hit 73. GFS led (off 1.0°F); ECMWF ran 4°F cool.
  • Sat Aug 29 7 days out the models said 66–71; it hit 70. UKMO led (off 0.1°F); AIGFS ran 6°F cool.
  • Fri Aug 28 6 days out the models said 63–73; it hit 77. GFS led (off 1.2°F); AIGFS ran 6°F cool.
  • Thu Aug 27 5 days out the models said 71–77; it hit 77. ECMWF led (off 0.1°F); AIFS ran 5°F cool.
  • Wed Aug 26 4 days out the models said 73–81; it hit 81. ICON led (off 0.9°F); AIFS ran 5°F cool.
  • Tue Aug 25 3 days out the models said 72–80; it hit 77. ECMWF led (off 0.1°F); AIGFS ran 3°F cool.
  • Wed Aug 19 8 days out the models said 68–78; it hit 74. UKMO led (off 0.1°F); AIGFS ran 3°F cool.
  • Tue Aug 18 7 days out the models said 68–76; it hit 74. AIFS led (off 0.2°F); GEM ran 4°F warm.
  • Mon Aug 17 6 days out the models said 66–75; it hit 78. ECMWF led (off 0.4°F); AIGFS ran 6°F cool.
  • Sun Aug 16 5 days out the models said 75–80; it hit 76. AIGFS led (off 0.8°F); GFS ran 7°F warm.
  • Sat Aug 15 4 days out the models said 73–82; it hit 80. ICON led (off 1.0°F); GEM ran 7°F warm.
  • Fri Aug 14 3 days out the models said 82–92; it hit 93. GEM led (off 0.5°F); AIGFS ran 4°F cool.

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