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

Chicago O'Hare · ECMWF IFS HRES · lead day 7

KORD · ifs_hres · lead 7

Target day = initialization date + 7 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
tmax00Zbilinear30d18 1 QC3.40 [2.25, 4.12]2.41-2.89 [-3.93, -0.97]4.13 [2.95, 4.79]6% [0%, 20%]33%56%+0.09+0.362026-08-08 → 2026-08-30
tmax00Zbilinear90d18 1 QC3.40 [1.32, 4.21]2.41-2.89 [-4.07, 0.93]4.13 [1.44, 4.96]6% [0%, 21%]33%56%+0.09+0.362026-08-08 → 2026-08-30
tmax00Zbilinear365d18 1 QC3.40 [1.25, 4.24]2.41-2.89 [-4.07, 0.87]4.13 [1.45, 4.93]6% [0%, 20%]33%56%+0.09+0.362026-08-08 → 2026-08-30
tmax00Zbilinearall18 1 QC3.40 [1.34, 4.19]2.41-2.89 [-4.06, 0.89]4.13 [1.53, 4.93]6% [0%, 22%]33%56%+0.09+0.362026-08-08 → 2026-08-30
tmax00Znearest30d18 1 QC3.14 [2.14, 3.79]2.23-2.59 [-3.59, -0.74]3.76 [2.79, 4.34]11% [0%, 40%]39%56%+0.16+0.412026-08-08 → 2026-08-30
tmax00Znearest90d18 1 QC3.14 [1.12, 3.83]2.23-2.59 [-3.75, 0.46]3.76 [1.43, 4.47]11% [0%, 67%]39%56%+0.16+0.412026-08-08 → 2026-08-30
tmax00Znearest365d18 1 QC3.14 [1.44, 3.87]2.23-2.59 [-3.81, 0.46]3.76 [1.72, 4.41]11% [0%, 58%]39%56%+0.16+0.412026-08-08 → 2026-08-30
tmax00Znearestall18 1 QC3.14 [1.43, 3.86]2.23-2.59 [-3.81, 0.46]3.76 [1.71, 4.41]11% [0%, 60%]39%56%+0.16+0.412026-08-08 → 2026-08-30
tmax12Zbilinear30d17 1 QC3.64 [2.15, 4.74]2.82-3.11 [-4.64, -0.98]4.57 [2.94, 5.53]24% [5%, 50%]35%47%+0.02+0.242026-08-08 → 2026-08-30
tmax12Zbilinear90d17 1 QC3.64 [1.80, 4.80]2.82-3.11 [-4.69, -0.78]4.57 [1.80, 5.56]24% [0%, 51%]35%47%+0.02+0.242026-08-08 → 2026-08-30
tmax12Zbilinear365d17 1 QC3.64 [1.80, 4.88]2.82-3.11 [-4.86, -0.63]4.57 [1.80, 5.64]24% [0%, 57%]35%47%+0.02+0.242026-08-08 → 2026-08-30
tmax12Zbilinearall17 1 QC3.64 [1.80, 5.01]2.82-3.11 [-5.01, -0.48]4.57 [1.80, 5.69]24% [0%, 56%]35%47%+0.02+0.242026-08-08 → 2026-08-30
tmax12Znearest30d17 1 QC3.53 [2.11, 4.56]2.79-2.82 [-4.38, -0.69]4.33 [2.80, 5.28]12% [0%, 33%]41%47%+0.05+0.252026-08-08 → 2026-08-30
tmax12Znearest90d17 1 QC3.53 [1.82, 4.60]2.79-2.82 [-4.44, -0.46]4.33 [1.91, 5.30]12% [0%, 38%]41%47%+0.05+0.252026-08-08 → 2026-08-30
tmax12Znearest365d17 1 QC3.53 [1.91, 4.68]2.79-2.82 [-4.68, -0.35]4.33 [1.91, 5.38]12% [0%, 38%]41%47%+0.05+0.252026-08-08 → 2026-08-30
tmax12Znearestall17 1 QC3.53 [1.79, 4.80]2.79-2.82 [-4.77, -0.21]4.33 [1.91, 5.46]12% [0%, 40%]41%47%+0.05+0.252026-08-08 → 2026-08-30
tmin00Zbilinear30d18 1 QC2.17 [1.39, 2.68]2.19+0.43 [-0.64, 1.34]2.72 [1.69, 3.27]33% [15%, 64%]61%67%+0.59+0.582026-08-08 → 2026-08-30
tmin00Zbilinear90d18 1 QC2.17 [1.25, 2.69]2.19+0.43 [-0.70, 1.43]2.72 [1.35, 3.26]33% [15%, 80%]61%67%+0.59+0.582026-08-08 → 2026-08-30
tmin00Zbilinear365d18 1 QC2.17 [1.17, 2.74]2.19+0.43 [-0.85, 1.42]2.72 [1.27, 3.30]33% [14%, 80%]61%67%+0.59+0.582026-08-08 → 2026-08-30
tmin00Zbilinearall18 1 QC2.17 [1.18, 2.74]2.19+0.43 [-0.83, 1.45]2.72 [1.30, 3.32]33% [13%, 81%]61%67%+0.59+0.582026-08-08 → 2026-08-30
tmin00Znearest30d18 1 QC2.43 [1.50, 2.98]2.40-0.24 [-1.33, 0.67]2.94 [2.09, 3.40]22% [7%, 56%]50%61%+0.54+0.532026-08-08 → 2026-08-30
tmin00Znearest90d18 1 QC2.43 [1.18, 2.99]2.40-0.24 [-1.36, 0.72]2.94 [1.67, 3.44]22% [7%, 80%]50%61%+0.54+0.532026-08-08 → 2026-08-30
tmin00Znearest365d18 1 QC2.43 [1.23, 3.04]2.40-0.24 [-1.48, 0.71]2.94 [1.64, 3.45]22% [7%, 76%]50%61%+0.54+0.532026-08-08 → 2026-08-30
tmin00Znearestall18 1 QC2.43 [1.13, 3.03]2.40-0.24 [-1.53, 0.75]2.94 [1.57, 3.44]22% [0%, 80%]50%61%+0.54+0.532026-08-08 → 2026-08-30
tmin12Zbilinear30d17 1 QC2.30 [1.88, 3.05]2.16+0.78 [-0.53, 1.73]2.76 [2.21, 3.47]24% [8%, 36%]59%71%+0.56+0.582026-08-08 → 2026-08-30
tmin12Zbilinear90d17 1 QC2.30 [1.86, 3.53]2.16+0.78 [-1.23, 1.85]2.76 [2.16, 3.83]24% [0%, 36%]59%71%+0.56+0.582026-08-08 → 2026-08-30
tmin12Zbilinear365d17 1 QC2.30 [1.83, 3.62]2.16+0.78 [-1.10, 1.80]2.76 [2.15, 3.87]24% [0%, 36%]59%71%+0.56+0.582026-08-08 → 2026-08-30
tmin12Zbilinearall17 1 QC2.30 [1.80, 3.60]2.16+0.78 [-1.11, 1.90]2.76 [2.10, 3.84]24% [0%, 36%]59%71%+0.56+0.582026-08-08 → 2026-08-30
tmin12Znearest30d17 1 QC2.10 [1.55, 3.01]2.10+0.14 [-1.12, 1.13]2.61 [1.96, 3.42]24% [7%, 36%]53%71%+0.60+0.602026-08-08 → 2026-08-30
tmin12Znearest90d17 1 QC2.10 [1.51, 3.57]2.10+0.14 [-1.79, 1.31]2.61 [1.92, 3.76]24% [0%, 37%]53%71%+0.60+0.602026-08-08 → 2026-08-30
tmin12Znearest365d17 1 QC2.10 [1.51, 3.54]2.10+0.14 [-1.73, 1.24]2.61 [1.89, 3.77]24% [0%, 38%]53%71%+0.60+0.602026-08-08 → 2026-08-30
tmin12Znearestall17 1 QC2.10 [1.44, 3.57]2.10+0.14 [-1.74, 1.36]2.61 [1.77, 3.79]24% [0%, 38%]53%71%+0.60+0.602026-08-08 → 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 7, 00Z bilinear tmax+10+50-5-102026-08-08: +1.02 °F2026-08-14: +2.03 °F2026-08-15: -0.28 °F2026-08-16: -4.2 °F2026-08-17: -7.14 °F2026-08-18: -1.49 °F2026-08-19: +1.59 °F2026-08-20: -1.87 °F2026-08-21: -7.99 °F2026-08-22: -2.65 °F2026-08-23: -4.99 °F2026-08-24: -2.02 °F2026-08-25: -1.04 °F2026-08-26: -4.22 °F2026-08-27: -3.06 °F2026-08-28: -4.99 °F2026-08-29: -8.15 °F2026-08-30: -2.49 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.49
2026-08-29-8.15
2026-08-28-4.99
2026-08-27-3.06
2026-08-26-4.22
2026-08-25-1.04
2026-08-24-2.02
2026-08-23-4.99
2026-08-22-2.65
2026-08-21-7.99
2026-08-20-1.87
2026-08-19+1.59
2026-08-18-1.49
2026-08-17-7.14
2026-08-16-4.20
2026-08-15-0.28
2026-08-14+2.03
2026-08-13—
2026-08-12—
2026-08-11—
2026-08-10—
2026-08-09—
2026-08-08+1.02

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KORD, lead day 7-10 to -9 °F: 0 days-9 to -8 °F: 1 day-8 to -7 °F: 2 days-7 to -6 °F: 0 days-6 to -5 °F: 0 days-5 to -4 °F: 4 days-4 to -3 °F: 1 day-3 to -2 °F: 3 days-2 to -1 °F: 3 days-1 to 0 °F: 1 day0 to 1 °F: 0 days1 to 2 °F: 2 days2 to 3 °F: 1 day3 to 4 °F: 0 days4 to 5 °F: 0 days5 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| 2.57 · P90 |e| 7.39 °F-100+10 °Fn = 18 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
-9.00-8.001
-8.00-7.002
-7.00-6.000
-6.00-5.000
-5.00-4.004
-4.00-3.001
-3.00-2.003
-2.00-1.003
-1.00+0.001
+0.00+1.000
+1.00+2.002
+2.00+3.001
+3.00+4.000
+4.00+5.000
+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
2026-08183.40 -2.89

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-08 → 2026-08-30 18
ECMWF IFS HRES2026-08-08 → 2026-08-30 18
ECMWF IFS HRES2026-08-08 → 2026-08-30 17
ECMWF IFS HRES2026-08-08 → 2026-08-30 17

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 18 -1.33 [-2.24, 0.57] no
NCEP GFS 18 -2.13 [-4.20, -1.13] yes
GraphCast (IFS init) 18 -0.51 [-2.52, 1.28] no
Persistence (baseline) 18 -0.32 [-6.72, 1.21] no

Cite this page

ShortCastCheck, KORD ifs_hres lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KORD/model/ifs_hres/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KORD (Chicago O'Hare), model ifs_hres, lead day 7. 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/7/

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