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

Chicago O'Hare · ECMWF IFS HRES · lead day 6

KORD · ifs_hres · lead 6

Target day = initialization date + 6 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
tmax00Zbilinear30d19 1 QC3.45 [2.59, 4.11]3.06-1.85 [-3.23, -0.00]4.04 [3.19, 4.52]16% [0%, 37%]32%47%+0.06+0.172026-08-07 → 2026-08-30
tmax00Zbilinear90d19 1 QC3.45 [2.51, 4.19]3.06-1.85 [-3.30, 0.36]4.04 [2.89, 4.56]16% [0%, 38%]32%47%+0.06+0.172026-08-07 → 2026-08-30
tmax00Zbilinear365d19 1 QC3.45 [2.52, 4.18]3.06-1.85 [-3.33, 0.50]4.04 [2.89, 4.55]16% [0%, 38%]32%47%+0.06+0.172026-08-07 → 2026-08-30
tmax00Zbilinearall19 1 QC3.45 [2.46, 4.16]3.06-1.85 [-3.56, 0.51]4.04 [2.89, 4.55]16% [0%, 38%]32%47%+0.06+0.172026-08-07 → 2026-08-30
tmax00Znearest30d19 1 QC3.37 [2.70, 3.96]3.02-1.58 [-3.06, 0.18]3.85 [3.17, 4.29]11% [0%, 25%]21%47%+0.08+0.182026-08-07 → 2026-08-30
tmax00Znearest90d19 1 QC3.37 [2.69, 4.01]3.02-1.58 [-3.14, 0.64]3.85 [3.08, 4.33]11% [0%, 26%]21%47%+0.08+0.182026-08-07 → 2026-08-30
tmax00Znearest365d19 1 QC3.37 [2.69, 4.02]3.02-1.58 [-3.16, 0.71]3.85 [3.08, 4.33]11% [0%, 26%]21%47%+0.08+0.182026-08-07 → 2026-08-30
tmax00Znearestall19 1 QC3.37 [2.61, 4.02]3.02-1.58 [-3.45, 0.71]3.85 [3.09, 4.32]11% [0%, 25%]21%47%+0.08+0.182026-08-07 → 2026-08-30
tmax12Zbilinear30d19 1 QC3.28 [2.73, 4.20]2.89-1.69 [-3.50, 0.16]4.06 [3.27, 4.93]16% [0%, 33%]26%63%+0.11+0.222026-08-07 → 2026-08-30
tmax12Zbilinear90d19 1 QC3.28 [2.65, 4.88]2.89-1.69 [-4.02, 0.42]4.06 [3.14, 5.44]16% [0%, 33%]26%63%+0.11+0.222026-08-07 → 2026-08-30
tmax12Zbilinear365d19 1 QC3.28 [2.62, 4.59]2.89-1.69 [-3.76, 0.69]4.06 [3.12, 5.31]16% [0%, 36%]26%63%+0.11+0.222026-08-07 → 2026-08-30
tmax12Zbilinearall19 1 QC3.28 [2.64, 4.63]2.89-1.69 [-4.15, 0.61]4.06 [3.13, 5.31]16% [0%, 37%]26%63%+0.11+0.222026-08-07 → 2026-08-30
tmax12Znearest30d19 1 QC3.19 [2.72, 4.01]2.92-1.53 [-3.31, 0.33]3.89 [3.20, 4.66]16% [0%, 26%]26%63%+0.13+0.212026-08-07 → 2026-08-30
tmax12Znearest90d19 1 QC3.19 [2.68, 4.72]2.92-1.53 [-3.83, 0.65]3.89 [3.12, 5.18]16% [0%, 27%]26%63%+0.13+0.212026-08-07 → 2026-08-30
tmax12Znearest365d19 1 QC3.19 [2.66, 4.34]2.92-1.53 [-3.53, 0.89]3.89 [3.08, 4.95]16% [0%, 27%]26%63%+0.13+0.212026-08-07 → 2026-08-30
tmax12Znearestall19 1 QC3.19 [2.65, 4.50]2.92-1.53 [-3.90, 0.87]3.89 [3.10, 4.99]16% [0%, 27%]26%63%+0.13+0.212026-08-07 → 2026-08-30
tmin00Zbilinear30d19 1 QC1.44 [1.05, 1.83]1.40+0.48 [-0.04, 0.96]1.81 [1.23, 2.37]42% [23%, 63%]84%95%+0.70+0.712026-08-07 → 2026-08-30
tmin00Zbilinear90d19 1 QC1.44 [0.97, 1.87]1.40+0.48 [-0.09, 1.08]1.81 [1.14, 2.41]42% [18%, 67%]84%95%+0.70+0.712026-08-07 → 2026-08-30
tmin00Zbilinear365d19 1 QC1.44 [0.93, 1.86]1.40+0.48 [-0.21, 1.12]1.81 [1.13, 2.39]42% [14%, 68%]84%95%+0.70+0.712026-08-07 → 2026-08-30
tmin00Zbilinearall19 1 QC1.44 [0.95, 1.85]1.40+0.48 [-0.16, 1.12]1.81 [1.08, 2.39]42% [14%, 67%]84%95%+0.70+0.712026-08-07 → 2026-08-30
tmin00Znearest30d19 1 QC1.30 [0.88, 1.77]1.30+0.05 [-0.53, 0.59]1.75 [0.98, 2.32]42% [25%, 60%]89%89%+0.73+0.732026-08-07 → 2026-08-30
tmin00Znearest90d19 1 QC1.30 [0.80, 1.77]1.30+0.05 [-0.58, 0.70]1.75 [0.92, 2.35]42% [22%, 63%]89%89%+0.73+0.732026-08-07 → 2026-08-30
tmin00Znearest365d19 1 QC1.30 [0.83, 1.79]1.30+0.05 [-0.66, 0.73]1.75 [0.93, 2.32]42% [21%, 67%]89%89%+0.73+0.732026-08-07 → 2026-08-30
tmin00Znearestall19 1 QC1.30 [0.82, 1.77]1.30+0.05 [-0.63, 0.74]1.75 [0.93, 2.32]42% [20%, 67%]89%89%+0.73+0.732026-08-07 → 2026-08-30
tmin12Zbilinear30d19 1 QC2.24 [1.61, 3.23]2.27+0.68 [-1.01, 1.56]2.80 [1.92, 3.74]26% [10%, 39%]47%74%+0.54+0.532026-08-07 → 2026-08-30
tmin12Zbilinear90d19 1 QC2.24 [1.53, 3.42]2.27+0.68 [-1.44, 1.54]2.80 [1.84, 3.77]26% [0%, 40%]47%74%+0.54+0.532026-08-07 → 2026-08-30
tmin12Zbilinear365d19 1 QC2.24 [1.51, 3.42]2.27+0.68 [-1.15, 1.65]2.80 [1.82, 3.87]26% [0%, 40%]47%74%+0.54+0.532026-08-07 → 2026-08-30
tmin12Zbilinearall19 1 QC2.24 [1.55, 3.43]2.27+0.68 [-1.33, 1.65]2.80 [1.81, 3.91]26% [0%, 43%]47%74%+0.54+0.532026-08-07 → 2026-08-30
tmin12Znearest30d19 1 QC2.30 [1.66, 3.37]2.30+0.13 [-1.42, 0.94]2.71 [1.86, 3.67]11% [0%, 17%]63%68%+0.53+0.522026-08-07 → 2026-08-30
tmin12Znearest90d19 1 QC2.30 [1.61, 3.72]2.30+0.13 [-2.03, 0.91]2.71 [1.78, 3.92]11% [0%, 17%]63%68%+0.53+0.522026-08-07 → 2026-08-30
tmin12Znearest365d19 1 QC2.30 [1.57, 3.69]2.30+0.13 [-1.72, 1.01]2.71 [1.76, 3.90]11% [0%, 17%]63%68%+0.53+0.522026-08-07 → 2026-08-30
tmin12Znearestall19 1 QC2.30 [1.59, 3.76]2.30+0.13 [-1.57, 1.03]2.71 [1.77, 4.02]11% [0%, 16%]63%68%+0.53+0.522026-08-07 → 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 6, 00Z bilinear tmax+10+50-5-102026-08-07: -2.89 °F2026-08-13: +1.71 °F2026-08-14: -2.9 °F2026-08-15: +1.29 °F2026-08-16: -7.02 °F2026-08-17: +0.99 °F2026-08-18: -0.91 °F2026-08-19: +0.68 °F2026-08-20: -7.62 °F2026-08-21: -3.05 °F2026-08-22: -3.59 °F2026-08-23: -3.52 °F2026-08-24: -6.41 °F2026-08-25: -3.34 °F2026-08-26: -2 °F2026-08-27: +2.83 °F2026-08-28: -7.13 °F2026-08-29: +3.13 °F2026-08-30: +4.49 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+4.49
2026-08-29+3.13
2026-08-28-7.13
2026-08-27+2.83
2026-08-26-2.00
2026-08-25-3.34
2026-08-24-6.41
2026-08-23-3.52
2026-08-22-3.59
2026-08-21-3.05
2026-08-20-7.62
2026-08-19+0.68
2026-08-18-0.91
2026-08-17+0.99
2026-08-16-7.02
2026-08-15+1.29
2026-08-14-2.90
2026-08-13+1.71
2026-08-12—
2026-08-11—
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07-2.89

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KORD, lead day 6-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 3 days-7 to -6 °F: 1 day-6 to -5 °F: 0 days-5 to -4 °F: 0 days-4 to -3 °F: 4 days-3 to -2 °F: 2 days-2 to -1 °F: 1 day-1 to 0 °F: 1 day0 to 1 °F: 2 days1 to 2 °F: 2 days2 to 3 °F: 1 day3 to 4 °F: 1 day4 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| 3.05 · P90 |e| 7.04 °F-100+10 °Fn = 19 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
-8.00-7.003
-7.00-6.001
-6.00-5.000
-5.00-4.000
-4.00-3.004
-3.00-2.002
-2.00-1.001
-1.00+0.001
+0.00+1.002
+1.00+2.002
+2.00+3.001
+3.00+4.001
+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
2026-08193.45 -1.85

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-07 → 2026-08-30 19
ECMWF IFS HRES2026-08-07 → 2026-08-30 19
ECMWF IFS HRES2026-08-07 → 2026-08-30 19
ECMWF IFS HRES2026-08-07 → 2026-08-30 19

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 19 -0.76 [-1.97, -0.00] yes
NCEP GFS 19 +1.11 [0.15, 2.27] yes
GraphCast (IFS init) 19 -0.61 [-2.77, 0.84] no
Persistence (baseline) 19 -0.24 [-6.87, 1.40] no

Cite this page

ShortCastCheck, KORD ifs_hres lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KORD/model/ifs_hres/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KORD (Chicago O'Hare), model ifs_hres, lead day 6. 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/6/

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