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

Chicago O'Hare · ECMWF IFS HRES · lead day 3

KORD · ifs_hres · lead 3

Target day = initialization date + 3 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, ifs-gpid161, starting 2026-08-01 — 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
tmax00Zbilinear30d22 1 QC2.62 [2.04, 3.39]2.14-1.54 [-2.64, -0.48]3.07 [2.46, 3.72]14% [0%, 26%]41%64%+0.20+0.362026-08-04 → 2026-08-30
tmax00Zbilinear90d22 1 QC2.62 [2.06, 3.58]2.14-1.54 [-3.19, -0.15]3.07 [2.49, 3.88]14% [0%, 27%]41%64%+0.20+0.362026-08-04 → 2026-08-30
tmax00Zbilinear365d22 1 QC2.62 [2.03, 3.57]2.14-1.54 [-3.27, 0.07]3.07 [2.43, 3.85]14% [0%, 27%]41%64%+0.20+0.362026-08-04 → 2026-08-30
tmax00Zbilinearall22 1 QC2.62 [2.03, 3.66]2.14-1.54 [-3.35, -0.02]3.07 [2.43, 3.97]14% [0%, 27%]41%64%+0.20+0.362026-08-04 → 2026-08-30
tmax00Znearest30d22 1 QC2.49 [1.91, 3.23]2.20-1.23 [-2.36, -0.14]2.97 [2.49, 3.57]18% [0%, 38%]50%64%+0.24+0.342026-08-04 → 2026-08-30
tmax00Znearest90d22 1 QC2.49 [1.94, 3.42]2.20-1.23 [-2.92, 0.15]2.97 [2.49, 3.73]18% [0%, 38%]50%64%+0.24+0.342026-08-04 → 2026-08-30
tmax00Znearest365d22 1 QC2.49 [1.85, 3.51]2.20-1.23 [-3.03, 0.32]2.97 [2.46, 3.72]18% [0%, 40%]50%64%+0.24+0.342026-08-04 → 2026-08-30
tmax00Znearestall22 1 QC2.49 [1.91, 3.65]2.20-1.23 [-3.14, 0.25]2.97 [2.45, 3.78]18% [0%, 38%]50%64%+0.24+0.342026-08-04 → 2026-08-30
tmax12Zbilinear30d22 1 QC2.89 [2.26, 3.89]2.22-1.84 [-2.93, -0.89]3.28 [2.63, 4.18]18% [0%, 35%]32%50%+0.12+0.342026-08-04 → 2026-08-30
tmax12Zbilinear90d22 1 QC2.89 [2.27, 4.15]2.22-1.84 [-3.40, -0.44]3.28 [2.67, 4.43]18% [0%, 36%]32%50%+0.12+0.342026-08-04 → 2026-08-30
tmax12Zbilinear365d22 1 QC2.89 [2.18, 4.20]2.22-1.84 [-3.52, -0.25]3.28 [2.55, 4.45]18% [0%, 38%]32%50%+0.12+0.342026-08-04 → 2026-08-30
tmax12Zbilinearall22 1 QC2.89 [2.26, 4.36]2.22-1.84 [-3.52, -0.32]3.28 [2.64, 4.59]18% [0%, 33%]32%50%+0.12+0.342026-08-04 → 2026-08-30
tmax12Znearest30d22 1 QC2.78 [2.13, 3.80]2.16-1.61 [-2.73, -0.64]3.14 [2.47, 4.11]14% [0%, 27%]32%64%+0.15+0.352026-08-04 → 2026-08-30
tmax12Znearest90d22 1 QC2.78 [2.15, 4.23]2.16-1.61 [-3.21, -0.21]3.14 [2.52, 4.45]14% [0%, 28%]32%64%+0.15+0.352026-08-04 → 2026-08-30
tmax12Znearest365d22 1 QC2.78 [2.10, 4.35]2.16-1.61 [-3.37, -0.08]3.14 [2.43, 4.61]14% [0%, 29%]32%64%+0.15+0.352026-08-04 → 2026-08-30
tmax12Znearestall22 1 QC2.78 [2.15, 4.34]2.16-1.61 [-3.38, -0.11]3.14 [2.52, 4.63]14% [0%, 27%]32%64%+0.15+0.352026-08-04 → 2026-08-30
tmin00Zbilinear30d22 1 QC1.79 [1.31, 2.32]1.76+0.39 [-1.04, 1.63]2.26 [1.69, 2.72]32% [15%, 47%]64%82%+0.55+0.562026-08-04 → 2026-08-30
tmin00Zbilinear90d22 1 QC1.79 [1.25, 2.42]1.76+0.39 [-1.26, 1.68]2.26 [1.57, 2.77]32% [9%, 50%]64%82%+0.55+0.562026-08-04 → 2026-08-30
tmin00Zbilinear365d22 1 QC1.79 [1.28, 2.53]1.76+0.39 [-1.27, 1.74]2.26 [1.57, 2.79]32% [10%, 50%]64%82%+0.55+0.562026-08-04 → 2026-08-30
tmin00Zbilinearall22 1 QC1.79 [1.27, 2.44]1.76+0.39 [-1.25, 1.63]2.26 [1.57, 2.73]32% [10%, 50%]64%82%+0.55+0.562026-08-04 → 2026-08-30
tmin00Znearest30d22 1 QC1.82 [1.42, 2.26]1.79-0.15 [-1.54, 1.07]2.25 [1.83, 2.63]32% [14%, 47%]59%86%+0.54+0.552026-08-04 → 2026-08-30
tmin00Znearest90d22 1 QC1.82 [1.37, 2.43]1.79-0.15 [-1.76, 1.14]2.25 [1.67, 2.73]32% [9%, 50%]59%86%+0.54+0.552026-08-04 → 2026-08-30
tmin00Znearest365d22 1 QC1.82 [1.39, 2.45]1.79-0.15 [-1.73, 1.18]2.25 [1.71, 2.73]32% [9%, 50%]59%86%+0.54+0.552026-08-04 → 2026-08-30
tmin00Znearestall22 1 QC1.82 [1.38, 2.41]1.79-0.15 [-1.78, 1.09]2.25 [1.68, 2.68]32% [10%, 48%]59%86%+0.54+0.552026-08-04 → 2026-08-30
tmin12Zbilinear30d22 1 QC1.79 [1.36, 2.26]1.72+0.30 [-0.88, 1.30]2.13 [1.62, 2.53]27% [7%, 44%]64%86%+0.55+0.572026-08-04 → 2026-08-30
tmin12Zbilinear90d22 1 QC1.79 [1.30, 2.30]1.72+0.30 [-1.14, 1.33]2.13 [1.58, 2.52]27% [0%, 50%]64%86%+0.55+0.572026-08-04 → 2026-08-30
tmin12Zbilinear365d22 1 QC1.79 [1.29, 2.33]1.72+0.30 [-1.12, 1.38]2.13 [1.56, 2.54]27% [0%, 50%]64%86%+0.55+0.572026-08-04 → 2026-08-30
tmin12Zbilinearall22 1 QC1.79 [1.27, 2.38]1.72+0.30 [-1.17, 1.35]2.13 [1.55, 2.58]27% [0%, 50%]64%86%+0.55+0.572026-08-04 → 2026-08-30
tmin12Znearest30d22 1 QC1.69 [1.26, 2.17]1.71-0.10 [-1.22, 0.83]2.08 [1.63, 2.43]41% [18%, 58%]59%91%+0.58+0.572026-08-04 → 2026-08-30
tmin12Znearest90d22 1 QC1.69 [1.18, 2.24]1.71-0.10 [-1.41, 0.86]2.08 [1.55, 2.43]41% [9%, 62%]59%91%+0.58+0.572026-08-04 → 2026-08-30
tmin12Znearest365d22 1 QC1.69 [1.14, 2.24]1.71-0.10 [-1.33, 0.91]2.08 [1.54, 2.42]41% [6%, 63%]59%91%+0.58+0.572026-08-04 → 2026-08-30
tmin12Znearestall22 1 QC1.69 [1.17, 2.27]1.71-0.10 [-1.41, 0.87]2.08 [1.54, 2.47]41% [6%, 62%]59%91%+0.58+0.572026-08-04 → 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 ECMWF IFS HRES at KORD, lead day 3, 00Z bilinear tmax+10+50-5-102026-08-04: -4.44 °F2026-08-10: -3.87 °F2026-08-11: +1.68 °F2026-08-12: -2.81 °F2026-08-13: +1.56 °F2026-08-14: -1.06 °F2026-08-15: +2.59 °F2026-08-16: -4.19 °F2026-08-17: -2.85 °F2026-08-18: +0.17 °F2026-08-19: -0.17 °F2026-08-20: -1.11 °F2026-08-21: -1.7 °F2026-08-22: -3.05 °F2026-08-23: -3.1 °F2026-08-24: -5.54 °F2026-08-25: -5.78 °F2026-08-26: -1.41 °F2026-08-27: -2.51 °F2026-08-28: -2.2 °F2026-08-29: +1 °F2026-08-30: +4.94 °F2026-08-042026-08-30°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 (27 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+4.94
2026-08-29+1.00
2026-08-28-2.20
2026-08-27-2.51
2026-08-26-1.41
2026-08-25-5.78
2026-08-24-5.54
2026-08-23-3.10
2026-08-22-3.05
2026-08-21-1.70
2026-08-20-1.11
2026-08-19-0.17
2026-08-18+0.17
2026-08-17-2.85
2026-08-16-4.19
2026-08-15+2.59
2026-08-14-1.06
2026-08-13+1.56
2026-08-12-2.81
2026-08-11+1.68
2026-08-10-3.87
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05—
2026-08-04-4.44

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KORD, lead day 3-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 2 days-5 to -4 °F: 2 days-4 to -3 °F: 3 days-3 to -2 °F: 4 days-2 to -1 °F: 4 days-1 to 0 °F: 1 day0 to 1 °F: 2 days1 to 2 °F: 2 days2 to 3 °F: 1 day3 to 4 °F: 0 days4 to 5 °F: 1 day5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.55 · P90 |e| 4.89 °F-100+10 °Fn = 22 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
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.002
-5.00-4.002
-4.00-3.003
-3.00-2.004
-2.00-1.004
-1.00+0.001
+0.00+1.002
+1.00+2.002
+2.00+3.001
+3.00+4.000
+4.00+5.001
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08222.62 -1.54

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-04 → 2026-08-30 22
ECMWF IFS HRES2026-08-04 → 2026-08-30 22
ECMWF IFS HRES2026-08-04 → 2026-08-30 22
ECMWF IFS HRES2026-08-04 → 2026-08-30 22

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means ECMWF IFS HRES has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 22 -0.97 [-2.78, 0.19] no
NCEP GFS 22 -0.93 [-1.90, 0.35] no
GraphCast (IFS init) 20 -1.40 [-3.53, -0.45] yes
Persistence (baseline) 22 -0.65 [-2.80, 0.70] no

Cite this page

ShortCastCheck, KORD ifs_hres lead 3, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KORD/model/ifs_hres/lead/3/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KORD (Chicago O'Hare), model ifs_hres, lead day 3. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KORD/model/ifs_hres/lead/3/

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