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

Chicago O'Hare · ECMWF IFS HRES · lead day 1

KORD · ifs_hres · lead 1

Target day = initialization date + 1 day. 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
tmax00Zbilinear30d23 1 QC2.98 [2.60, 3.37]1.77-2.01 [-2.90, -1.02]3.44 [2.84, 3.91]0% [0%, 0%]30%61%-0.05+0.372026-08-02 → 2026-08-30
tmax00Zbilinear90d23 1 QC2.98 [2.53, 3.49]1.77-2.01 [-3.27, -0.80]3.44 [2.73, 3.96]0% [0%, 0%]30%61%-0.05+0.372026-08-02 → 2026-08-30
tmax00Zbilinear365d23 1 QC2.98 [2.51, 3.44]1.77-2.01 [-3.31, -0.66]3.44 [2.70, 3.91]0% [0%, 0%]30%61%-0.05+0.372026-08-02 → 2026-08-30
tmax00Zbilinearall23 1 QC2.98 [2.55, 3.49]1.77-2.01 [-3.34, -0.85]3.44 [2.81, 3.95]0% [0%, 0%]30%61%-0.05+0.372026-08-02 → 2026-08-30
tmax00Znearest30d23 1 QC2.71 [2.24, 3.18]1.87-1.76 [-2.73, -0.71]3.35 [2.57, 3.93]17% [5%, 27%]48%61%+0.04+0.332026-08-02 → 2026-08-30
tmax00Znearest90d23 1 QC2.71 [2.21, 3.15]1.87-1.76 [-3.04, -0.49]3.35 [2.47, 3.89]17% [0%, 28%]48%61%+0.04+0.332026-08-02 → 2026-08-30
tmax00Znearest365d23 1 QC2.71 [2.19, 3.16]1.87-1.76 [-3.09, -0.37]3.35 [2.47, 3.91]17% [0%, 27%]48%61%+0.04+0.332026-08-02 → 2026-08-30
tmax00Znearestall23 1 QC2.71 [2.24, 3.22]1.87-1.76 [-3.09, -0.46]3.35 [2.50, 3.95]17% [0%, 29%]48%61%+0.04+0.332026-08-02 → 2026-08-30
tmax12Zbilinear30d24 1 QC2.81 [2.34, 3.37]1.58-2.58 [-3.27, -1.89]3.25 [2.86, 3.81]17% [4%, 33%]29%58%+0.01+0.442026-08-02 → 2026-08-30
tmax12Zbilinear90d24 1 QC2.81 [2.26, 3.75]1.58-2.58 [-3.65, -1.82]3.25 [2.73, 4.22]17% [0%, 35%]29%58%+0.01+0.442026-08-02 → 2026-08-30
tmax12Zbilinear365d24 1 QC2.81 [2.19, 3.71]1.58-2.58 [-3.69, -1.69]3.25 [2.71, 4.07]17% [0%, 36%]29%58%+0.01+0.442026-08-02 → 2026-08-30
tmax12Zbilinearall24 1 QC2.81 [2.25, 3.77]1.58-2.58 [-3.65, -1.77]3.25 [2.78, 4.20]17% [0%, 35%]29%58%+0.01+0.442026-08-02 → 2026-08-30
tmax12Znearest30d24 1 QC2.61 [2.13, 3.13]1.56-2.25 [-3.03, -1.45]3.03 [2.64, 3.50]17% [4%, 33%]38%62%+0.08+0.452026-08-02 → 2026-08-30
tmax12Znearest90d24 1 QC2.61 [2.10, 3.42]1.56-2.25 [-3.32, -1.39]3.03 [2.59, 3.78]17% [0%, 35%]38%62%+0.08+0.452026-08-02 → 2026-08-30
tmax12Znearest365d24 1 QC2.61 [2.04, 3.36]1.56-2.25 [-3.32, -1.27]3.03 [2.52, 3.68]17% [0%, 36%]38%62%+0.08+0.452026-08-02 → 2026-08-30
tmax12Znearestall24 1 QC2.61 [2.10, 3.42]1.56-2.25 [-3.37, -1.34]3.03 [2.60, 3.79]17% [0%, 35%]38%62%+0.08+0.452026-08-02 → 2026-08-30
tmin00Zbilinear30d23 1 QC1.57 [1.31, 1.85]1.55+0.48 [-0.17, 1.13]1.91 [1.69, 2.11]35% [13%, 52%]65%87%+0.46+0.472026-08-02 → 2026-08-30
tmin00Zbilinear90d23 1 QC1.57 [1.30, 1.86]1.55+0.48 [-0.23, 1.26]1.91 [1.69, 2.08]35% [10%, 53%]65%87%+0.46+0.472026-08-02 → 2026-08-30
tmin00Zbilinear365d23 1 QC1.57 [1.27, 1.86]1.55+0.48 [-0.28, 1.26]1.91 [1.70, 2.09]35% [9%, 57%]65%87%+0.46+0.472026-08-02 → 2026-08-30
tmin00Zbilinearall23 1 QC1.57 [1.28, 1.88]1.55+0.48 [-0.25, 1.41]1.91 [1.69, 2.10]35% [8%, 56%]65%87%+0.46+0.472026-08-02 → 2026-08-30
tmin00Znearest30d23 1 QC1.44 [1.21, 1.74]1.44-0.04 [-0.67, 0.61]1.79 [1.47, 2.07]48% [26%, 63%]70%96%+0.50+0.502026-08-02 → 2026-08-30
tmin00Znearest90d23 1 QC1.44 [1.20, 1.75]1.44-0.04 [-0.69, 0.76]1.79 [1.45, 2.07]48% [20%, 64%]70%96%+0.50+0.502026-08-02 → 2026-08-30
tmin00Znearest365d23 1 QC1.44 [1.18, 1.76]1.44-0.04 [-0.74, 0.77]1.79 [1.42, 2.08]48% [20%, 65%]70%96%+0.50+0.502026-08-02 → 2026-08-30
tmin00Znearestall23 1 QC1.44 [1.18, 1.78]1.44-0.04 [-0.73, 0.93]1.79 [1.44, 2.08]48% [20%, 67%]70%96%+0.50+0.502026-08-02 → 2026-08-30
tmin12Zbilinear30d24 1 QC1.47 [1.12, 1.79]1.49+0.16 [-0.67, 0.94]1.94 [1.56, 2.20]46% [27%, 63%]75%88%+0.49+0.482026-08-02 → 2026-08-30
tmin12Zbilinear90d24 1 QC1.47 [1.10, 1.79]1.49+0.16 [-0.75, 1.02]1.94 [1.45, 2.14]46% [25%, 67%]75%88%+0.49+0.482026-08-02 → 2026-08-30
tmin12Zbilinear365d24 1 QC1.47 [1.10, 1.80]1.49+0.16 [-0.79, 1.05]1.94 [1.47, 2.16]46% [23%, 70%]75%88%+0.49+0.482026-08-02 → 2026-08-30
tmin12Zbilinearall24 1 QC1.47 [1.10, 1.80]1.49+0.16 [-0.70, 1.15]1.94 [1.39, 2.18]46% [22%, 67%]75%88%+0.49+0.482026-08-02 → 2026-08-30
tmin12Znearest30d24 1 QC1.42 [1.14, 1.63]1.37-0.29 [-1.05, 0.42]1.81 [1.33, 2.13]46% [26%, 64%]75%88%+0.51+0.522026-08-02 → 2026-08-30
tmin12Znearest90d24 1 QC1.42 [1.10, 1.64]1.37-0.29 [-1.13, 0.52]1.81 [1.28, 2.09]46% [21%, 67%]75%88%+0.51+0.522026-08-02 → 2026-08-30
tmin12Znearest365d24 1 QC1.42 [1.10, 1.63]1.37-0.29 [-1.13, 0.55]1.81 [1.26, 2.12]46% [21%, 70%]75%88%+0.51+0.522026-08-02 → 2026-08-30
tmin12Znearestall24 1 QC1.42 [1.08, 1.65]1.37-0.29 [-1.08, 0.68]1.81 [1.22, 2.13]46% [20%, 67%]75%88%+0.51+0.522026-08-02 → 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 1, 00Z bilinear tmax+10+50-5-102026-08-02: -4.13 °F2026-08-09: -1.51 °F2026-08-10: -5.53 °F2026-08-11: -2 °F2026-08-12: -1.65 °F2026-08-13: -3.41 °F2026-08-14: -1.62 °F2026-08-15: +7.39 °F2026-08-16: -2.98 °F2026-08-17: -1.65 °F2026-08-18: -2.05 °F2026-08-19: -3.12 °F2026-08-20: -1.28 °F2026-08-21: -2.58 °F2026-08-22: -3.93 °F2026-08-23: -3.4 °F2026-08-24: -1.15 °F2026-08-25: -3.28 °F2026-08-26: -7.52 °F2026-08-27: -2.43 °F2026-08-28: -2.13 °F2026-08-29: +1.5 °F2026-08-30: +2.25 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+2.25
2026-08-29+1.50
2026-08-28-2.13
2026-08-27-2.43
2026-08-26-7.52
2026-08-25-3.28
2026-08-24-1.15
2026-08-23-3.40
2026-08-22-3.93
2026-08-21-2.58
2026-08-20-1.28
2026-08-19-3.12
2026-08-18-2.05
2026-08-17-1.65
2026-08-16-2.98
2026-08-15+7.39
2026-08-14-1.62
2026-08-13-3.41
2026-08-12-1.65
2026-08-11-2.00
2026-08-10-5.53
2026-08-09-1.51
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05—
2026-08-04—
2026-08-03—
2026-08-02-4.13

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KORD, lead day 1-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 1 day-7 to -6 °F: 0 days-6 to -5 °F: 1 day-5 to -4 °F: 1 day-4 to -3 °F: 5 days-3 to -2 °F: 6 days-2 to -1 °F: 6 days-1 to 0 °F: 0 days0 to 1 °F: 0 days1 to 2 °F: 1 day2 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: 1 day8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.43 · P90 |e| 5.25 °F-100+10 °Fn = 23 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
-8.00-7.001
-7.00-6.000
-6.00-5.001
-5.00-4.001
-4.00-3.005
-3.00-2.006
-2.00-1.006
-1.00+0.000
+0.00+1.000
+1.00+2.001
+2.00+3.001
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.001
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08232.98 -2.01

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-02 → 2026-08-30 23
ECMWF IFS HRES2026-08-02 → 2026-08-30 23
ECMWF IFS HRES2026-08-02 → 2026-08-30 24
ECMWF IFS HRES2026-08-02 → 2026-08-30 24

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 23 -0.15 [-1.07, 0.67] no
Aurora (GFS init) 1 -4.45 [-4.45, -4.45] yes
Aurora (IFS init) 2 -0.82 [-1.19, -0.45] yes
FourCastNet v2 (GFS init) 1 -0.38 [-0.38, -0.38] yes
FourCastNet v2 (IFS init) 2 -0.58 [-1.21, 0.05] no
NCEP GFS 23 +0.48 [-0.80, 1.12] no
GraphCast (GFS init) 1 -4.70 [-4.70, -4.70] yes
GraphCast (IFS init) 21 -0.00 [-0.62, 0.68] no
Pangu-Weather (GFS init) 1 -1.98 [-1.98, -1.98] yes
Pangu-Weather (IFS init) 2 -2.15 [-2.71, -1.59] yes
Persistence (baseline) 23 +0.15 [-0.71, 0.95] no

Cite this page

ShortCastCheck, KORD ifs_hres lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KORD/model/ifs_hres/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KORD (Chicago O'Hare), model ifs_hres, lead day 1. 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/1/

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