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

Chicago O'Hare · ECMWF IFS HRES · lead day 5

KORD · ifs_hres · lead 5

Target day = initialization date + 5 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 QC2.79 [2.06, 3.45]2.45-1.17 [-2.41, 0.29]3.26 [2.50, 3.81]17% [0%, 31%]28%67%+0.20+0.302026-08-06 → 2026-08-30
tmax00Zbilinear90d18 1 QC2.79 [1.97, 3.56]2.45-1.17 [-2.54, 0.68]3.26 [2.41, 3.87]17% [0%, 31%]28%67%+0.20+0.302026-08-06 → 2026-08-30
tmax00Zbilinear365d18 1 QC2.79 [2.00, 3.57]2.45-1.17 [-2.74, 0.69]3.26 [2.41, 3.88]17% [0%, 33%]28%67%+0.20+0.302026-08-06 → 2026-08-30
tmax00Zbilinearall18 1 QC2.79 [1.98, 3.58]2.45-1.17 [-2.80, 0.83]3.26 [2.43, 3.92]17% [0%, 31%]28%67%+0.20+0.302026-08-06 → 2026-08-30
tmax00Znearest30d18 1 QC2.69 [2.06, 3.35]2.39-0.84 [-2.10, 0.65]3.22 [2.41, 3.93]17% [6%, 29%]39%61%+0.23+0.322026-08-06 → 2026-08-30
tmax00Znearest90d18 1 QC2.69 [2.06, 3.53]2.39-0.84 [-2.57, 0.99]3.22 [2.37, 4.10]17% [0%, 29%]39%61%+0.23+0.322026-08-06 → 2026-08-30
tmax00Znearest365d18 1 QC2.69 [2.02, 3.55]2.39-0.84 [-2.66, 1.00]3.22 [2.33, 4.12]17% [0%, 29%]39%61%+0.23+0.322026-08-06 → 2026-08-30
tmax00Znearestall18 1 QC2.69 [2.05, 3.53]2.39-0.84 [-2.66, 1.14]3.22 [2.34, 4.15]17% [0%, 29%]39%61%+0.23+0.322026-08-06 → 2026-08-30
tmax12Zbilinear30d20 1 QC2.31 [1.65, 4.13]1.72-1.41 [-3.37, -0.34]3.03 [1.90, 5.30]15% [0%, 32%]60%75%+0.38+0.542026-08-06 → 2026-08-30
tmax12Zbilinear90d20 1 QC2.31 [1.59, 5.48]1.72-1.41 [-4.30, -0.17]3.03 [1.87, 6.54]15% [0%, 35%]60%75%+0.38+0.542026-08-06 → 2026-08-30
tmax12Zbilinear365d20 1 QC2.31 [1.57, 5.00]1.72-1.41 [-4.81, -0.03]3.03 [1.81, 6.04]15% [0%, 33%]60%75%+0.38+0.542026-08-06 → 2026-08-30
tmax12Zbilinearall20 1 QC2.31 [1.59, 4.85]1.72-1.41 [-4.10, -0.18]3.03 [1.86, 6.13]15% [0%, 33%]60%75%+0.38+0.542026-08-06 → 2026-08-30
tmax12Znearest30d20 1 QC2.19 [1.53, 4.08]1.79-1.26 [-3.22, -0.22]2.98 [1.82, 5.34]30% [14%, 43%]60%85%+0.41+0.522026-08-06 → 2026-08-30
tmax12Znearest90d20 1 QC2.19 [1.51, 5.47]1.79-1.26 [-4.24, -0.04]2.98 [1.78, 6.57]30% [11%, 43%]60%85%+0.41+0.522026-08-06 → 2026-08-30
tmax12Znearest365d20 1 QC2.19 [1.49, 4.95]1.79-1.26 [-4.84, 0.06]2.98 [1.74, 6.04]30% [0%, 43%]60%85%+0.41+0.522026-08-06 → 2026-08-30
tmax12Znearestall20 1 QC2.19 [1.48, 4.86]1.79-1.26 [-3.98, -0.07]2.98 [1.74, 6.16]30% [0%, 43%]60%85%+0.41+0.522026-08-06 → 2026-08-30
tmin00Zbilinear30d18 1 QC2.35 [1.58, 3.36]2.27+0.86 [-1.27, 2.38]2.99 [2.01, 3.92]22% [0%, 39%]61%67%+0.51+0.522026-08-06 → 2026-08-30
tmin00Zbilinear90d18 1 QC2.35 [1.40, 3.40]2.27+0.86 [-1.82, 2.46]2.99 [1.81, 3.96]22% [0%, 43%]61%67%+0.51+0.522026-08-06 → 2026-08-30
tmin00Zbilinear365d18 1 QC2.35 [1.40, 3.59]2.27+0.86 [-1.58, 2.52]2.99 [1.76, 4.11]22% [0%, 44%]61%67%+0.51+0.522026-08-06 → 2026-08-30
tmin00Zbilinearall18 1 QC2.35 [1.35, 3.53]2.27+0.86 [-1.46, 2.32]2.99 [1.72, 4.06]22% [0%, 43%]61%67%+0.51+0.522026-08-06 → 2026-08-30
tmin00Znearest30d18 1 QC2.29 [1.58, 3.45]2.29+0.33 [-1.83, 1.82]2.92 [2.13, 3.85]33% [0%, 58%]56%61%+0.52+0.522026-08-06 → 2026-08-30
tmin00Znearest90d18 1 QC2.29 [1.41, 3.61]2.29+0.33 [-2.49, 1.90]2.92 [1.92, 3.96]33% [0%, 59%]56%61%+0.52+0.522026-08-06 → 2026-08-30
tmin00Znearest365d18 1 QC2.29 [1.43, 3.85]2.29+0.33 [-2.20, 1.95]2.92 [1.97, 4.00]33% [0%, 61%]56%61%+0.52+0.522026-08-06 → 2026-08-30
tmin00Znearestall18 1 QC2.29 [1.46, 3.83]2.29+0.33 [-2.18, 1.77]2.92 [1.99, 3.96]33% [0%, 67%]56%61%+0.52+0.522026-08-06 → 2026-08-30
tmin12Zbilinear30d20 1 QC2.31 [1.59, 3.04]2.26+0.55 [-1.12, 1.69]3.05 [1.88, 3.93]20% [6%, 32%]60%80%+0.49+0.502026-08-06 → 2026-08-30
tmin12Zbilinear90d20 1 QC2.31 [1.37, 3.04]2.26+0.55 [-1.35, 1.86]3.05 [1.37, 3.92]20% [0%, 33%]60%80%+0.49+0.502026-08-06 → 2026-08-30
tmin12Zbilinear365d20 1 QC2.31 [1.37, 3.05]2.26+0.55 [-1.37, 1.84]3.05 [1.37, 3.97]20% [0%, 33%]60%80%+0.49+0.502026-08-06 → 2026-08-30
tmin12Zbilinearall20 1 QC2.31 [1.28, 3.07]2.26+0.55 [-1.29, 1.76]3.05 [1.33, 3.98]20% [0%, 33%]60%80%+0.49+0.502026-08-06 → 2026-08-30
tmin12Znearest30d20 1 QC2.17 [1.47, 3.01]2.17+0.01 [-1.63, 1.20]2.94 [1.91, 3.79]30% [6%, 48%]70%80%+0.52+0.512026-08-06 → 2026-08-30
tmin12Znearest90d20 1 QC2.17 [1.44, 2.98]2.17+0.01 [-1.84, 1.32]2.94 [1.82, 3.77]30% [0%, 50%]70%80%+0.52+0.512026-08-06 → 2026-08-30
tmin12Znearest365d20 1 QC2.17 [1.41, 3.01]2.17+0.01 [-1.84, 1.30]2.94 [1.83, 3.79]30% [0%, 50%]70%80%+0.52+0.512026-08-06 → 2026-08-30
tmin12Znearestall20 1 QC2.17 [1.40, 3.07]2.17+0.01 [-1.81, 1.22]2.94 [1.70, 3.82]30% [0%, 50%]70%80%+0.52+0.512026-08-06 → 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 5, 00Z bilinear tmax+10+50-5-102026-08-06: -2.46 °F2026-08-12: -4.57 °F2026-08-13: +5.02 °F2026-08-14: -2.18 °F2026-08-16: +0.18 °F2026-08-17: -2.97 °F2026-08-19: +4.1 °F2026-08-20: -1.57 °F2026-08-21: -2.13 °F2026-08-22: -6.64 °F2026-08-23: -4.14 °F2026-08-24: -2.8 °F2026-08-25: -2.48 °F2026-08-26: -2.99 °F2026-08-27: -0.65 °F2026-08-28: -0.02 °F2026-08-29: +1.28 °F2026-08-30: +3.98 °F2026-08-062026-08-30°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 (25 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+3.98
2026-08-29+1.28
2026-08-28-0.02
2026-08-27-0.65
2026-08-26-2.99
2026-08-25-2.48
2026-08-24-2.80
2026-08-23-4.14
2026-08-22-6.64
2026-08-21-2.13
2026-08-20-1.57
2026-08-19+4.10
2026-08-18—
2026-08-17-2.97
2026-08-16+0.18
2026-08-15—
2026-08-14-2.18
2026-08-13+5.02
2026-08-12-4.57
2026-08-11—
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06-2.46

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KORD, lead day 5-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 1 day-6 to -5 °F: 0 days-5 to -4 °F: 2 days-4 to -3 °F: 0 days-3 to -2 °F: 7 days-2 to -1 °F: 1 day-1 to 0 °F: 2 days0 to 1 °F: 1 day1 to 2 °F: 1 day2 to 3 °F: 0 days3 to 4 °F: 1 day4 to 5 °F: 1 day5 to 6 °F: 1 day6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.64 · P90 |e| 4.71 °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
-9.00-8.000
-8.00-7.000
-7.00-6.001
-6.00-5.000
-5.00-4.002
-4.00-3.000
-3.00-2.007
-2.00-1.001
-1.00+0.002
+0.00+1.001
+1.00+2.001
+2.00+3.000
+3.00+4.001
+4.00+5.001
+5.00+6.001
+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
2026-08182.79 -1.17

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-06 → 2026-08-30 18
ECMWF IFS HRES2026-08-06 → 2026-08-30 18
ECMWF IFS HRES2026-08-06 → 2026-08-30 20
ECMWF IFS HRES2026-08-06 → 2026-08-30 20

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 -0.46 [-2.44, 0.91] no
NCEP GFS 18 -0.65 [-3.32, 1.74] no
GraphCast (IFS init) 18 -0.80 [-2.81, 0.82] no
Persistence (baseline) 18 -0.71 [-3.12, 0.34] no

Cite this page

ShortCastCheck, KORD ifs_hres lead 5, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KORD/model/ifs_hres/lead/5/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KORD (Chicago O'Hare), model ifs_hres, lead day 5. 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/5/

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