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

Chicago O'Hare · ECMWF AIFS Single · lead day 5

KORD · aifs_single · 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, 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
tmax00Zbilinear30d25 1 QC3.47 [2.68, 4.38]2.16-2.99 [-3.88, -2.17]4.08 [3.18, 4.94]12% [0%, 23%]24%52%+0.06+0.422026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC3.47 [2.62, 4.62]2.16-2.99 [-4.06, -1.99]4.08 [3.07, 5.15]12% [0%, 24%]24%52%+0.06+0.422026-08-06 → 2026-08-30
tmax00Zbilinear365d25 1 QC3.47 [2.58, 4.50]2.16-2.99 [-4.08, -2.05]4.08 [3.00, 5.09]12% [0%, 25%]24%52%+0.06+0.422026-08-06 → 2026-08-30
tmax00Zbilinearall25 1 QC3.47 [2.63, 4.61]2.16-2.99 [-4.06, -1.85]4.08 [3.10, 5.06]12% [0%, 24%]24%52%+0.06+0.422026-08-06 → 2026-08-30
tmax00Znearest30d25 1 QC3.21 [2.42, 4.16]2.16-2.53 [-3.43, -1.67]3.80 [2.84, 4.71]12% [0%, 23%]36%56%+0.13+0.422026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC3.21 [2.38, 4.49]2.16-2.53 [-3.73, -1.50]3.80 [2.72, 4.96]12% [0%, 24%]36%56%+0.13+0.422026-08-06 → 2026-08-30
tmax00Znearest365d25 1 QC3.21 [2.35, 4.37]2.16-2.53 [-3.62, -1.58]3.80 [2.65, 4.88]12% [0%, 24%]36%56%+0.13+0.422026-08-06 → 2026-08-30
tmax00Znearestall25 1 QC3.21 [2.39, 4.39]2.16-2.53 [-3.63, -1.35]3.80 [2.78, 4.85]12% [0%, 24%]36%56%+0.13+0.422026-08-06 → 2026-08-30
tmax12Zbilinear30d24 1 QC3.52 [2.74, 4.52]2.21-2.98 [-3.78, -2.24]4.08 [3.15, 5.03]8% [0%, 19%]29%46%+0.03+0.392026-08-06 → 2026-08-30
tmax12Zbilinear90d24 1 QC3.52 [2.69, 4.77]2.21-2.98 [-3.96, -2.15]4.08 [3.02, 5.30]8% [0%, 22%]29%46%+0.03+0.392026-08-06 → 2026-08-30
tmax12Zbilinear365d24 1 QC3.52 [2.67, 4.57]2.21-2.98 [-3.77, -2.11]4.08 [2.98, 5.14]8% [0%, 22%]29%46%+0.03+0.392026-08-06 → 2026-08-30
tmax12Zbilinearall24 1 QC3.52 [2.62, 4.60]2.21-2.98 [-3.89, -2.05]4.08 [2.90, 5.21]8% [0%, 22%]29%46%+0.03+0.392026-08-06 → 2026-08-30
tmax12Znearest30d24 1 QC3.22 [2.35, 4.43]2.25-2.52 [-3.32, -1.76]3.80 [2.81, 4.88]17% [5%, 28%]38%46%+0.11+0.382026-08-06 → 2026-08-30
tmax12Znearest90d24 1 QC3.22 [2.27, 4.74]2.25-2.52 [-3.55, -1.68]3.80 [2.70, 5.13]17% [0%, 29%]38%46%+0.11+0.382026-08-06 → 2026-08-30
tmax12Znearest365d24 1 QC3.22 [2.22, 4.58]2.25-2.52 [-3.37, -1.62]3.80 [2.55, 5.03]17% [0%, 29%]38%46%+0.11+0.382026-08-06 → 2026-08-30
tmax12Znearestall24 1 QC3.22 [2.20, 4.67]2.25-2.52 [-3.50, -1.59]3.80 [2.54, 5.07]17% [0%, 29%]38%46%+0.11+0.382026-08-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC2.24 [1.78, 2.65]2.20+0.62 [-0.79, 1.72]2.69 [2.17, 3.12]32% [19%, 45%]48%72%+0.47+0.482026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC2.24 [1.75, 2.68]2.20+0.62 [-1.22, 1.84]2.69 [2.12, 3.16]32% [17%, 46%]48%72%+0.47+0.482026-08-06 → 2026-08-30
tmin00Zbilinear365d25 1 QC2.24 [1.72, 2.71]2.20+0.62 [-1.44, 1.86]2.69 [2.10, 3.18]32% [17%, 47%]48%72%+0.47+0.482026-08-06 → 2026-08-30
tmin00Zbilinearall25 1 QC2.24 [1.72, 2.67]2.20+0.62 [-1.35, 1.79]2.69 [2.09, 3.12]32% [17%, 48%]48%72%+0.47+0.482026-08-06 → 2026-08-30
tmin00Znearest30d25 1 QC2.32 [1.99, 2.62]2.32-0.04 [-1.46, 1.10]2.71 [2.43, 3.00]20% [11%, 29%]52%52%+0.45+0.452026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC2.32 [1.97, 2.62]2.32-0.04 [-1.94, 1.25]2.71 [2.39, 3.00]20% [11%, 30%]52%52%+0.45+0.452026-08-06 → 2026-08-30
tmin00Znearest365d25 1 QC2.32 [1.91, 2.66]2.32-0.04 [-2.20, 1.23]2.71 [2.35, 3.03]20% [10%, 30%]52%52%+0.45+0.452026-08-06 → 2026-08-30
tmin00Znearestall25 1 QC2.32 [1.91, 2.58]2.32-0.04 [-2.01, 1.10]2.71 [2.36, 2.96]20% [10%, 31%]52%52%+0.45+0.452026-08-06 → 2026-08-30
tmin12Zbilinear30d24 1 QC2.04 [1.46, 2.54]2.01+0.60 [-0.50, 1.55]2.55 [1.98, 2.98]29% [11%, 52%]54%71%+0.53+0.542026-08-06 → 2026-08-30
tmin12Zbilinear90d24 1 QC2.04 [1.38, 2.56]2.01+0.60 [-0.83, 1.70]2.55 [1.80, 3.04]29% [10%, 52%]54%71%+0.53+0.542026-08-06 → 2026-08-30
tmin12Zbilinear365d24 1 QC2.04 [1.31, 2.61]2.01+0.60 [-0.89, 1.68]2.55 [1.77, 3.04]29% [8%, 56%]54%71%+0.53+0.542026-08-06 → 2026-08-30
tmin12Zbilinearall24 1 QC2.04 [1.31, 2.57]2.01+0.60 [-0.83, 1.61]2.55 [1.76, 3.02]29% [8%, 56%]54%71%+0.53+0.542026-08-06 → 2026-08-30
tmin12Znearest30d24 1 QC2.11 [1.66, 2.48]2.10-0.06 [-1.19, 0.93]2.56 [2.16, 2.88]21% [4%, 40%]58%67%+0.51+0.522026-08-06 → 2026-08-30
tmin12Znearest90d24 1 QC2.11 [1.64, 2.48]2.10-0.06 [-1.56, 1.09]2.56 [2.17, 2.88]21% [5%, 44%]58%67%+0.51+0.522026-08-06 → 2026-08-30
tmin12Znearest365d24 1 QC2.11 [1.61, 2.52]2.10-0.06 [-1.63, 1.03]2.56 [2.12, 2.92]21% [0%, 43%]58%67%+0.51+0.522026-08-06 → 2026-08-30
tmin12Znearestall24 1 QC2.11 [1.56, 2.49]2.10-0.06 [-1.55, 0.98]2.56 [2.07, 2.89]21% [3%, 44%]58%67%+0.51+0.522026-08-06 → 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 AIFS Single at KORD, lead day 5, 00Z bilinear tmax+10+50-5-102026-08-06: -4.91 °F2026-08-07: -6.54 °F2026-08-08: +1.22 °F2026-08-09: -2.12 °F2026-08-10: -8.42 °F2026-08-11: -5.45 °F2026-08-12: -5.07 °F2026-08-13: +0.16 °F2026-08-14: -1.01 °F2026-08-15: -1.78 °F2026-08-16: -2.51 °F2026-08-17: -5.09 °F2026-08-18: -2.75 °F2026-08-19: +0.71 °F2026-08-20: -2.98 °F2026-08-21: +0.41 °F2026-08-22: -2.87 °F2026-08-23: -4.58 °F2026-08-24: -3.84 °F2026-08-25: -4.5 °F2026-08-26: -2.31 °F2026-08-27: -3.59 °F2026-08-28: -7.91 °F2026-08-29: -2.49 °F2026-08-30: +3.48 °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+3.48
2026-08-29-2.49
2026-08-28-7.91
2026-08-27-3.59
2026-08-26-2.31
2026-08-25-4.50
2026-08-24-3.84
2026-08-23-4.58
2026-08-22-2.87
2026-08-21+0.41
2026-08-20-2.98
2026-08-19+0.71
2026-08-18-2.75
2026-08-17-5.09
2026-08-16-2.51
2026-08-15-1.78
2026-08-14-1.01
2026-08-13+0.16
2026-08-12-5.07
2026-08-11-5.45
2026-08-10-8.42
2026-08-09-2.12
2026-08-08+1.22
2026-08-07-6.54
2026-08-06-4.91

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KORD, lead day 5-10 to -9 °F: 0 days-9 to -8 °F: 1 day-8 to -7 °F: 1 day-7 to -6 °F: 1 day-6 to -5 °F: 3 days-5 to -4 °F: 3 days-4 to -3 °F: 2 days-3 to -2 °F: 7 days-2 to -1 °F: 2 days-1 to 0 °F: 0 days0 to 1 °F: 3 days1 to 2 °F: 1 day2 to 3 °F: 0 days3 to 4 °F: 1 day4 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| 2.98 · P90 |e| 6.1 °F-100+10 °Fn = 25 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
-9.00-8.001
-8.00-7.001
-7.00-6.001
-6.00-5.003
-5.00-4.003
-4.00-3.002
-3.00-2.007
-2.00-1.002
-1.00+0.000
+0.00+1.003
+1.00+2.001
+2.00+3.000
+3.00+4.001
+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
2026-08253.47 -2.99

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-06 → 2026-08-30 25
ECMWF AIFS Single2026-08-06 → 2026-08-30 25
ECMWF AIFS Single2026-08-06 → 2026-08-30 24
ECMWF AIFS Single2026-08-06 → 2026-08-30 24

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 25 +0.07 [-1.18, 1.76] no
GraphCast (IFS init) 25 -0.20 [-0.68, 0.34] no
ECMWF IFS HRES 18 +0.46 [-0.91, 2.44] no
Persistence (baseline) 25 -0.21 [-1.51, 1.02] no

Cite this page

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

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