Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

Chicago O'Hare · ECMWF IFS HRES · lead day 2

KORD · ifs_hres · lead 2

Target day = initialization date + 2 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 QC2.77 [2.28, 3.75]2.07-1.90 [-2.68, -1.13]3.28 [2.64, 4.44]18% [0%, 34%]41%59%+0.08+0.322026-08-03 → 2026-08-30
tmax00Zbilinear90d22 1 QC2.77 [2.28, 4.12]2.07-1.90 [-3.19, -0.66]3.28 [2.58, 4.89]18% [0%, 34%]41%59%+0.08+0.322026-08-03 → 2026-08-30
tmax00Zbilinear365d22 1 QC2.77 [2.23, 3.97]2.07-1.90 [-3.31, -0.46]3.28 [2.53, 4.72]18% [0%, 36%]41%59%+0.08+0.322026-08-03 → 2026-08-30
tmax00Zbilinearall22 1 QC2.77 [2.23, 4.29]2.07-1.90 [-3.37, -0.73]3.28 [2.54, 5.02]18% [0%, 35%]41%59%+0.08+0.322026-08-03 → 2026-08-30
tmax00Znearest30d22 1 QC2.62 [2.15, 3.49]2.03-1.70 [-2.43, -0.89]3.13 [2.51, 4.10]14% [0%, 28%]45%68%+0.13+0.332026-08-03 → 2026-08-30
tmax00Znearest90d22 1 QC2.62 [2.17, 3.76]2.03-1.70 [-2.95, -0.40]3.13 [2.45, 4.46]14% [0%, 27%]45%68%+0.13+0.332026-08-03 → 2026-08-30
tmax00Znearest365d22 1 QC2.62 [2.12, 3.67]2.03-1.70 [-2.99, -0.27]3.13 [2.37, 4.32]14% [0%, 29%]45%68%+0.13+0.332026-08-03 → 2026-08-30
tmax00Znearestall22 1 QC2.62 [2.10, 3.99]2.03-1.70 [-3.08, -0.52]3.13 [2.41, 4.55]14% [0%, 28%]45%68%+0.13+0.332026-08-03 → 2026-08-30
tmax12Zbilinear30d22 1 QC2.64 [2.20, 3.24]1.77-2.29 [-2.94, -1.59]3.12 [2.65, 3.89]18% [4%, 36%]45%59%+0.13+0.432026-08-03 → 2026-08-30
tmax12Zbilinear90d22 1 QC2.64 [2.09, 3.64]1.77-2.29 [-3.45, -1.23]3.12 [2.50, 4.32]18% [0%, 38%]45%59%+0.13+0.432026-08-03 → 2026-08-30
tmax12Zbilinear365d22 1 QC2.64 [2.06, 3.56]1.77-2.29 [-3.47, -1.03]3.12 [2.46, 4.18]18% [0%, 38%]45%59%+0.13+0.432026-08-03 → 2026-08-30
tmax12Zbilinearall22 1 QC2.64 [2.10, 3.68]1.77-2.29 [-3.47, -1.21]3.12 [2.50, 4.38]18% [0%, 36%]45%59%+0.13+0.432026-08-03 → 2026-08-30
tmax12Znearest30d22 1 QC2.51 [2.04, 3.09]1.78-2.05 [-2.67, -1.32]2.94 [2.46, 3.61]23% [12%, 36%]45%59%+0.18+0.422026-08-03 → 2026-08-30
tmax12Znearest90d22 1 QC2.51 [1.92, 3.44]1.78-2.05 [-3.13, -0.95]2.94 [2.34, 3.95]23% [10%, 40%]45%59%+0.18+0.422026-08-03 → 2026-08-30
tmax12Znearest365d22 1 QC2.51 [1.86, 3.38]1.78-2.05 [-3.14, -0.83]2.94 [2.24, 3.84]23% [9%, 41%]45%59%+0.18+0.422026-08-03 → 2026-08-30
tmax12Znearestall22 1 QC2.51 [1.93, 3.45]1.78-2.05 [-3.13, -0.95]2.94 [2.32, 3.95]23% [9%, 39%]45%59%+0.18+0.422026-08-03 → 2026-08-30
tmin00Zbilinear30d22 1 QC1.60 [1.20, 2.09]1.40+1.05 [0.24, 1.92]2.13 [1.57, 2.64]45% [33%, 57%]68%82%+0.50+0.562026-08-03 → 2026-08-30
tmin00Zbilinear90d22 1 QC1.60 [1.09, 2.25]1.40+1.05 [0.18, 2.05]2.13 [1.45, 2.77]45% [33%, 56%]68%82%+0.50+0.562026-08-03 → 2026-08-30
tmin00Zbilinear365d22 1 QC1.60 [1.09, 2.23]1.40+1.05 [0.12, 2.08]2.13 [1.39, 2.76]45% [31%, 56%]68%82%+0.50+0.562026-08-03 → 2026-08-30
tmin00Zbilinearall22 1 QC1.60 [1.11, 2.27]1.40+1.05 [0.16, 2.09]2.13 [1.43, 2.79]45% [31%, 56%]68%82%+0.50+0.562026-08-03 → 2026-08-30
tmin00Znearest30d22 1 QC1.32 [0.93, 1.78]1.36+0.56 [-0.20, 1.37]1.88 [1.34, 2.33]50% [33%, 63%]77%82%+0.59+0.582026-08-03 → 2026-08-30
tmin00Znearest90d22 1 QC1.32 [0.83, 1.88]1.36+0.56 [-0.23, 1.59]1.88 [1.21, 2.41]50% [33%, 65%]77%82%+0.59+0.582026-08-03 → 2026-08-30
tmin00Znearest365d22 1 QC1.32 [0.88, 1.85]1.36+0.56 [-0.28, 1.55]1.88 [1.23, 2.37]50% [31%, 65%]77%82%+0.59+0.582026-08-03 → 2026-08-30
tmin00Znearestall22 1 QC1.32 [0.82, 1.91]1.36+0.56 [-0.26, 1.65]1.88 [1.18, 2.42]50% [31%, 67%]77%82%+0.59+0.582026-08-03 → 2026-08-30
tmin12Zbilinear30d22 1 QC1.55 [1.14, 1.98]1.56+0.13 [-0.76, 0.91]2.03 [1.56, 2.37]41% [20%, 60%]68%86%+0.53+0.522026-08-03 → 2026-08-30
tmin12Zbilinear90d22 1 QC1.55 [1.09, 2.05]1.56+0.13 [-0.97, 1.11]2.03 [1.45, 2.35]41% [15%, 60%]68%86%+0.53+0.522026-08-03 → 2026-08-30
tmin12Zbilinear365d22 1 QC1.55 [1.11, 2.07]1.56+0.13 [-1.04, 1.15]2.03 [1.52, 2.38]41% [14%, 62%]68%86%+0.53+0.522026-08-03 → 2026-08-30
tmin12Zbilinearall22 1 QC1.55 [1.13, 2.12]1.56+0.13 [-0.91, 1.11]2.03 [1.52, 2.41]41% [13%, 62%]68%86%+0.53+0.522026-08-03 → 2026-08-30
tmin12Znearest30d22 1 QC1.54 [1.19, 1.86]1.48-0.42 [-1.19, 0.30]1.96 [1.30, 2.36]36% [18%, 50%]77%91%+0.53+0.552026-08-03 → 2026-08-30
tmin12Znearest90d22 1 QC1.54 [1.16, 1.85]1.48-0.42 [-1.34, 0.52]1.96 [1.28, 2.31]36% [12%, 50%]77%91%+0.53+0.552026-08-03 → 2026-08-30
tmin12Znearest365d22 1 QC1.54 [1.16, 1.85]1.48-0.42 [-1.42, 0.55]1.96 [1.27, 2.32]36% [14%, 52%]77%91%+0.53+0.552026-08-03 → 2026-08-30
tmin12Znearestall22 1 QC1.54 [1.14, 1.87]1.48-0.42 [-1.31, 0.46]1.96 [1.27, 2.34]36% [11%, 53%]77%91%+0.53+0.552026-08-03 → 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 2, 00Z bilinear tmax+10+50-5-102026-08-03: -7.93 °F2026-08-08: -2.15 °F2026-08-09: +1.13 °F2026-08-11: -2.71 °F2026-08-13: -4.87 °F2026-08-14: -1.17 °F2026-08-15: +3.5 °F2026-08-16: -5.5 °F2026-08-17: -1.94 °F2026-08-18: -0.35 °F2026-08-19: -3.37 °F2026-08-20: -0.62 °F2026-08-21: -0.88 °F2026-08-22: -3.9 °F2026-08-23: -2.96 °F2026-08-24: -4.13 °F2026-08-25: -1.96 °F2026-08-26: -0.85 °F2026-08-27: -2.69 °F2026-08-28: -3.4 °F2026-08-29: +1.89 °F2026-08-30: +3.04 °F2026-08-032026-08-30°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 (28 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+3.04
2026-08-29+1.89
2026-08-28-3.40
2026-08-27-2.69
2026-08-26-0.85
2026-08-25-1.96
2026-08-24-4.13
2026-08-23-2.96
2026-08-22-3.90
2026-08-21-0.88
2026-08-20-0.62
2026-08-19-3.37
2026-08-18-0.35
2026-08-17-1.94
2026-08-16-5.50
2026-08-15+3.50
2026-08-14-1.17
2026-08-13-4.87
2026-08-12—
2026-08-11-2.71
2026-08-10—
2026-08-09+1.13
2026-08-08-2.15
2026-08-07—
2026-08-06—
2026-08-05—
2026-08-04—
2026-08-03-7.93

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KORD, lead day 2-10 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: 2 days-4 to -3 °F: 3 days-3 to -2 °F: 4 days-2 to -1 °F: 3 days-1 to 0 °F: 4 days0 to 1 °F: 0 days1 to 2 °F: 2 days2 to 3 °F: 0 days3 to 4 °F: 2 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| 2.7 · P90 |e| 4.8 °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
-8.00-7.001
-7.00-6.000
-6.00-5.001
-5.00-4.002
-4.00-3.003
-3.00-2.004
-2.00-1.003
-1.00+0.004
+0.00+1.000
+1.00+2.002
+2.00+3.000
+3.00+4.002
+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
2026-08222.77 -1.90

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-03 → 2026-08-30 22
ECMWF IFS HRES2026-08-03 → 2026-08-30 22
ECMWF IFS HRES2026-08-03 → 2026-08-30 22
ECMWF IFS HRES2026-08-03 → 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 -0.29 [-1.26, 0.76] no
Aurora (IFS init) 1 +1.62 [1.62, 1.62] yes
FourCastNet v2 (IFS init) 1 +3.02 [3.02, 3.02] yes
NCEP GFS 22 -0.11 [-0.89, 0.75] no
GraphCast (IFS init) 20 -1.01 [-2.41, 0.09] no
Pangu-Weather (IFS init) 1 +1.60 [1.60, 1.60] yes
Persistence (baseline) 22 -0.23 [-0.86, 0.53] no

Cite this page

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

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

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