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CastCheck methodology v0.2 · data through 2026-08-30

Chicago O'Hare · Pangu-Weather (GFS init) · lead day 0

KORD · pangu_gfs · lead 0

Target day = initialization date + 0 days. This page is a permanent link: the numbers change as history accumulates, the address and the methodology version do not.

Scores use the latest model version segment, PANG_v100, starting 2026-08-28 — days before that ran a different version of the model and are excluded rather than silently pooled. Of the scored days, 1 carry a QC flag on the observation.

JSON for this page CSV of the daily errors Cite this page

Every number for this combination

All four windows × both initializations × both interpolations × both variables. Errors are computed in °C and shown in °F; CI is a 95 % moving-block bootstrap interval. MAE debiased and skill, debiased remove the constant offset of the window first, so a station that the model always reads a degree too warm is not scored as if it had no skill — compare the two skill columns to see how much of the error is a fixed offset. n QC next to n counts days whose observation carries a QC flag.

VariableInitMethod Windown MAE °F MAE debiased Bias °F RMSE °F ±1 °F±2 °F±3 °F Skill Skill, debiased Period
tmax00Zbilinear30d2 1 QC2.36 [2.16, 2.56]0.20-2.36 [-2.56, -2.16]2.37 [2.16, 2.56]0% [0%, 0%]0%100%——2026-08-29 → 2026-08-30
tmax00Zbilinear90d2 1 QC2.36 [2.16, 2.56]0.20-2.36 [-2.56, -2.16]2.37 [2.16, 2.56]0% [0%, 0%]0%100%——2026-08-29 → 2026-08-30
tmax00Zbilinear365d2 1 QC2.36 [2.16, 2.56]0.20-2.36 [-2.56, -2.16]2.37 [2.16, 2.56]0% [0%, 0%]0%100%——2026-08-29 → 2026-08-30
tmax00Zbilinearall2 1 QC2.36 [2.16, 2.56]0.20-2.36 [-2.56, -2.16]2.37 [2.16, 2.56]0% [0%, 0%]0%100%——2026-08-29 → 2026-08-30
tmax00Znearest30d2 1 QC2.10 [1.84, 2.35]0.25-2.10 [-2.35, -1.84]2.11 [1.84, 2.35]0% [0%, 0%]50%100%——2026-08-29 → 2026-08-30
tmax00Znearest90d2 1 QC2.10 [1.84, 2.35]0.25-2.10 [-2.35, -1.84]2.11 [1.84, 2.35]0% [0%, 0%]50%100%——2026-08-29 → 2026-08-30
tmax00Znearest365d2 1 QC2.10 [1.84, 2.35]0.25-2.10 [-2.35, -1.84]2.11 [1.84, 2.35]0% [0%, 0%]50%100%——2026-08-29 → 2026-08-30
tmax00Znearestall2 1 QC2.10 [1.84, 2.35]0.25-2.10 [-2.35, -1.84]2.11 [1.84, 2.35]0% [0%, 0%]50%100%——2026-08-29 → 2026-08-30
tmin00Zbilinear30d2 1 QC1.79 [1.78, 1.80]0.01+1.79 [1.78, 1.80]1.79 [1.78, 1.80]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinear90d2 1 QC1.79 [1.78, 1.80]0.01+1.79 [1.78, 1.80]1.79 [1.78, 1.80]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinear365d2 1 QC1.79 [1.78, 1.80]0.01+1.79 [1.78, 1.80]1.79 [1.78, 1.80]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinearall2 1 QC1.79 [1.78, 1.80]0.01+1.79 [1.78, 1.80]1.79 [1.78, 1.80]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearest30d2 1 QC1.41 [1.27, 1.54]0.14+1.41 [1.27, 1.54]1.41 [1.27, 1.54]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearest90d2 1 QC1.41 [1.27, 1.54]0.14+1.41 [1.27, 1.54]1.41 [1.27, 1.54]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearest365d2 1 QC1.41 [1.27, 1.54]0.14+1.41 [1.27, 1.54]1.41 [1.27, 1.54]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearestall2 1 QC1.41 [1.27, 1.54]0.14+1.41 [1.27, 1.54]1.41 [1.27, 1.54]0% [0%, 0%]100%100%——2026-08-29 → 2026-08-30

+ model too warm · − model too cold · bias interval includes zero · ★ lowest MAE · = not distinguishable from the leader · ▼ significantly worse · n < 30 greyed and unranked · CI is a 95 % moving-block bootstrap interval.

Daily error, last 90 days

Daily forecast minus observed error in °F for Pangu-Weather (GFS init) at KORD, lead day 0, 00Z bilinear tmax+5+2.50-2.5-52026-08-29: -2.56 °F2026-08-30: -2.16 °F2026-08-292026-08-30°F, forecast − observed
Forecast − observed, °F, 00Z bilinear daily maximum. The dashed line is zero; the thick line is a centred 7-day mean, drawn only where the whole window is present. Gaps are days with no score, never interpolation. Hover a point for its date and value.
The same series as a table (2 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.16
2026-08-29-2.56

Error distribution

Distribution of the signed daily error in °F for Pangu-Weather (GFS init) at KORD, lead day 0-5 to -4.5 °F: 0 days-4.5 to -4 °F: 0 days-4 to -3.5 °F: 0 days-3.5 to -3 °F: 0 days-3 to -2.5 °F: 1 day-2.5 to -2 °F: 1 day-2 to -1.5 °F: 0 days-1.5 to -1 °F: 0 days-1 to -0.5 °F: 0 days-0.5 to 0 °F: 0 days0 to 0.5 °F: 0 days0.5 to 1 °F: 0 days1 to 1.5 °F: 0 days1.5 to 2 °F: 0 days2 to 2.5 °F: 0 days2.5 to 3 °F: 0 days3 to 3.5 °F: 0 days3.5 to 4 °F: 0 days4 to 4.5 °F: 0 days4.5 to 5 °F: 0 daysdashed: P50 |e| 2.36 · P90 |e| 2.52 °F-50+5 °Fn = 2 days
All scored days for 00Z bilinear daily maximum, 20 equal bins. The dashed marks are the 50th and 90th percentiles of the absolute error, mirrored on both sides. Hover a bar for its bin and count.
Bin counts as a table
From °FTo °FDays
-5.00-4.500
-4.50-4.000
-4.00-3.500
-3.50-3.000
-3.00-2.501
-2.50-2.001
-2.00-1.500
-1.50-1.000
-1.00-0.500
-0.50+0.000
+0.00+0.500
+0.50+1.000
+1.00+1.500
+1.50+2.000
+2.00+2.500
+2.50+3.000
+3.00+3.500
+3.50+4.000
+4.00+4.500
+4.50+5.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-0822.36 -2.36

Availability

ModelScored period DaysCoverage
Pangu-Weather (GFS init)2026-08-29 → 2026-08-30 2
Pangu-Weather (GFS init)2026-08-29 → 2026-08-30 2

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means Pangu-Weather (GFS init) has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 2 -1.13 [-1.86, -0.40] yes
Aurora (GFS init) 2 -2.75 [-5.06, -0.43] yes
Aurora (IFS init) 2 -0.24 [-0.61, 0.13] no
FourCastNet v2 (GFS init) 2 +0.84 [0.42, 1.26] yes
FourCastNet v2 (IFS init) 2 -0.19 [-0.20, -0.18] yes
NCEP GFS 2 -1.24 [-2.05, -0.43] yes
GraphCast (GFS init) 2 -1.16 [-2.33, 0.02] no
GraphCast (IFS init) 2 -1.35 [-2.40, -0.30] yes
ECMWF IFS HRES 2 +1.62 [1.41, 1.83] yes
Pangu-Weather (IFS init) 2 -0.06 [-0.95, 0.82] no

Cite this page

ShortCastCheck, KORD pangu_gfs lead 0, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KORD/model/pangu_gfs/lead/0/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KORD (Chicago O'Hare), model pangu_gfs, lead day 0. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KORD/model/pangu_gfs/lead/0/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

JSON CSV all scores methodology v0.2 licence