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

Chicago O'Hare · ECMWF AIFS Single · lead day 7

KORD · aifs_single · 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, aifs-single-gpid5, 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 QC4.66 [3.47, 5.89]2.45-4.45 [-5.47, -3.30]5.57 [3.99, 7.03]9% [0%, 20%]13%30%-0.22+0.362026-08-08 → 2026-08-30
tmax00Zbilinear90d23 1 QC4.66 [3.42, 6.20]2.45-4.45 [-5.61, -3.09]5.57 [3.87, 7.43]9% [0%, 25%]13%30%-0.22+0.362026-08-08 → 2026-08-30
tmax00Zbilinear365d23 1 QC4.66 [3.42, 6.08]2.45-4.45 [-5.58, -3.16]5.57 [3.84, 7.25]9% [0%, 25%]13%30%-0.22+0.362026-08-08 → 2026-08-30
tmax00Zbilinearall23 1 QC4.66 [3.25, 6.08]2.45-4.45 [-5.61, -2.73]5.57 [3.71, 7.34]9% [0%, 22%]13%30%-0.22+0.362026-08-08 → 2026-08-30
tmax00Znearest30d23 1 QC4.34 [3.23, 5.52]2.44-4.03 [-4.92, -2.94]5.24 [3.72, 6.62]13% [5%, 24%]17%30%-0.13+0.362026-08-08 → 2026-08-30
tmax00Znearest90d23 1 QC4.34 [3.21, 5.88]2.44-4.03 [-5.08, -2.72]5.24 [3.58, 7.06]13% [2%, 25%]17%30%-0.13+0.362026-08-08 → 2026-08-30
tmax00Znearest365d23 1 QC4.34 [3.10, 5.71]2.44-4.03 [-5.03, -2.77]5.24 [3.52, 6.85]13% [0%, 25%]17%30%-0.13+0.362026-08-08 → 2026-08-30
tmax00Znearestall23 1 QC4.34 [3.08, 5.83]2.44-4.03 [-5.07, -2.37]5.24 [3.39, 6.94]13% [0%, 25%]17%30%-0.13+0.362026-08-08 → 2026-08-30
tmax12Zbilinear30d23 1 QC4.60 [3.35, 5.88]2.89-4.38 [-5.84, -3.03]5.60 [4.18, 6.84]4% [0%, 12%]26%48%-0.20+0.242026-08-08 → 2026-08-30
tmax12Zbilinear90d23 1 QC4.60 [3.33, 6.35]2.89-4.38 [-6.35, -3.02]5.60 [4.20, 7.24]4% [0%, 12%]26%48%-0.20+0.242026-08-08 → 2026-08-30
tmax12Zbilinear365d23 1 QC4.60 [3.24, 6.31]2.89-4.38 [-6.31, -2.90]5.60 [4.06, 7.12]4% [0%, 13%]26%48%-0.20+0.242026-08-08 → 2026-08-30
tmax12Zbilinearall23 1 QC4.60 [3.08, 6.35]2.89-4.38 [-6.35, -2.81]5.60 [3.74, 7.21]4% [0%, 13%]26%48%-0.20+0.242026-08-08 → 2026-08-30
tmax12Znearest30d23 1 QC4.21 [3.04, 5.47]2.90-3.94 [-5.40, -2.61]5.26 [3.89, 6.45]9% [0%, 23%]35%52%-0.10+0.242026-08-08 → 2026-08-30
tmax12Znearest90d23 1 QC4.21 [3.03, 5.90]2.90-3.94 [-5.90, -2.60]5.26 [3.90, 6.82]9% [0%, 24%]35%52%-0.10+0.242026-08-08 → 2026-08-30
tmax12Znearest365d23 1 QC4.21 [2.93, 5.87]2.90-3.94 [-5.87, -2.46]5.26 [3.71, 6.71]9% [0%, 25%]35%52%-0.10+0.242026-08-08 → 2026-08-30
tmax12Znearestall23 1 QC4.21 [2.74, 5.89]2.90-3.94 [-5.89, -2.38]5.26 [3.43, 6.79]9% [0%, 25%]35%52%-0.10+0.242026-08-08 → 2026-08-30
tmin00Zbilinear30d23 1 QC2.55 [2.05, 3.21]2.56-0.28 [-1.82, 1.09]3.27 [2.61, 4.10]30% [19%, 42%]52%65%+0.45+0.462026-08-08 → 2026-08-30
tmin00Zbilinear90d23 1 QC2.55 [2.01, 3.42]2.56-0.28 [-2.27, 1.30]3.27 [2.55, 4.31]30% [18%, 43%]52%65%+0.45+0.462026-08-08 → 2026-08-30
tmin00Zbilinear365d23 1 QC2.55 [1.98, 3.36]2.56-0.28 [-2.45, 1.47]3.27 [2.52, 4.30]30% [17%, 43%]52%65%+0.45+0.462026-08-08 → 2026-08-30
tmin00Zbilinearall23 1 QC2.55 [1.97, 3.29]2.56-0.28 [-2.45, 1.37]3.27 [2.48, 4.26]30% [17%, 43%]52%65%+0.45+0.462026-08-08 → 2026-08-30
tmin00Znearest30d23 1 QC2.82 [2.30, 3.49]2.65-0.97 [-2.59, 0.50]3.53 [2.83, 4.50]30% [14%, 43%]39%57%+0.39+0.442026-08-08 → 2026-08-30
tmin00Znearest90d23 1 QC2.82 [2.22, 3.67]2.65-0.97 [-3.07, 0.73]3.53 [2.80, 4.71]30% [12%, 45%]39%57%+0.39+0.442026-08-08 → 2026-08-30
tmin00Znearest365d23 1 QC2.82 [2.23, 3.65]2.65-0.97 [-3.25, 0.91]3.53 [2.78, 4.75]30% [10%, 44%]39%57%+0.39+0.442026-08-08 → 2026-08-30
tmin00Znearestall23 1 QC2.82 [2.24, 3.60]2.65-0.97 [-3.18, 0.81]3.53 [2.74, 4.74]30% [14%, 44%]39%57%+0.39+0.442026-08-08 → 2026-08-30
tmin12Zbilinear30d23 1 QC1.98 [1.58, 2.44]1.98+0.07 [-1.25, 1.19]2.51 [2.05, 2.99]39% [21%, 56%]57%78%+0.57+0.582026-08-08 → 2026-08-30
tmin12Zbilinear90d23 1 QC1.98 [1.55, 2.50]1.98+0.07 [-1.71, 1.45]2.51 [1.99, 3.05]39% [20%, 56%]57%78%+0.57+0.582026-08-08 → 2026-08-30
tmin12Zbilinear365d23 1 QC1.98 [1.57, 2.51]1.98+0.07 [-1.74, 1.39]2.51 [2.02, 3.03]39% [14%, 57%]57%78%+0.57+0.582026-08-08 → 2026-08-30
tmin12Zbilinearall23 1 QC1.98 [1.53, 2.50]1.98+0.07 [-1.74, 1.37]2.51 [1.94, 3.07]39% [17%, 57%]57%78%+0.57+0.582026-08-08 → 2026-08-30
tmin12Znearest30d23 1 QC2.15 [1.68, 2.74]2.03-0.59 [-1.98, 0.61]2.70 [2.16, 3.31]30% [12%, 48%]61%65%+0.54+0.572026-08-08 → 2026-08-30
tmin12Znearest90d23 1 QC2.15 [1.62, 2.93]2.03-0.59 [-2.40, 0.87]2.70 [2.07, 3.46]30% [11%, 50%]61%65%+0.54+0.572026-08-08 → 2026-08-30
tmin12Znearest365d23 1 QC2.15 [1.65, 2.91]2.03-0.59 [-2.55, 0.89]2.70 [2.11, 3.44]30% [9%, 50%]61%65%+0.54+0.572026-08-08 → 2026-08-30
tmin12Znearestall23 1 QC2.15 [1.62, 2.88]2.03-0.59 [-2.52, 0.85]2.70 [2.07, 3.43]30% [11%, 56%]61%65%+0.54+0.572026-08-08 → 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 AIFS Single at KORD, lead day 7, 00Z bilinear tmax+20+100-10-202026-08-08: -0.14 °F2026-08-09: -5.06 °F2026-08-10: -7.08 °F2026-08-11: -3.55 °F2026-08-12: -4.33 °F2026-08-13: -2.1 °F2026-08-14: -2.95 °F2026-08-15: -3.22 °F2026-08-16: -5.63 °F2026-08-17: -3.71 °F2026-08-18: -2.05 °F2026-08-19: -0.39 °F2026-08-20: -6.04 °F2026-08-21: -9.94 °F2026-08-22: -3.49 °F2026-08-23: -5.69 °F2026-08-24: -4.66 °F2026-08-25: -4.87 °F2026-08-26: -1.68 °F2026-08-27: -6.96 °F2026-08-28: -14.18 °F2026-08-29: -7.11 °F2026-08-30: +2.38 °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+2.38
2026-08-29-7.11
2026-08-28-14.18
2026-08-27-6.96
2026-08-26-1.68
2026-08-25-4.87
2026-08-24-4.66
2026-08-23-5.69
2026-08-22-3.49
2026-08-21-9.94
2026-08-20-6.04
2026-08-19-0.39
2026-08-18-2.05
2026-08-17-3.71
2026-08-16-5.63
2026-08-15-3.22
2026-08-14-2.95
2026-08-13-2.10
2026-08-12-4.33
2026-08-11-3.55
2026-08-10-7.08
2026-08-09-5.06
2026-08-08-0.14

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KORD, lead day 7-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 1 day-14 to -12 °F: 0 days-12 to -10 °F: 0 days-10 to -8 °F: 1 day-8 to -6 °F: 4 days-6 to -4 °F: 6 days-4 to -2 °F: 7 days-2 to 0 °F: 3 days0 to 2 °F: 0 days2 to 4 °F: 1 day4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 4.33 · P90 |e| 7.11 °F-200+20 °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
-20.00-18.000
-18.00-16.000
-16.00-14.001
-14.00-12.000
-12.00-10.000
-10.00-8.001
-8.00-6.004
-6.00-4.006
-4.00-2.007
-2.00+0.003
+0.00+2.000
+2.00+4.001
+4.00+6.000
+6.00+8.000
+8.00+10.000
+10.00+12.000
+12.00+14.000
+14.00+16.000
+16.00+18.000
+18.00+20.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08234.66 -4.45

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means ECMWF AIFS Single has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
NCEP GFS 23 -0.95 [-2.66, 0.84] no
GraphCast (IFS init) 23 +0.44 [-0.85, 2.00] no
ECMWF IFS HRES 18 +1.33 [-0.57, 2.24] no
Persistence (baseline) 23 +0.84 [-1.98, 2.99] no

Cite this page

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

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