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

Oklahoma City · GraphCast (IFS init) · lead day 4

KOKC · graphcast_ifs · lead 4

Target day = initialization date + 4 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, GRAP_v100, starting 2026-01-01 — 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 QC8.44 [7.45, 9.66]2.20-8.44 [-9.66, -7.45]8.84 [7.71, 10.00]0% [0%, 0%]0%0%-1.25+0.412026-08-05 → 2026-08-29
tmax00Zbilinear90d25 1 QC8.44 [7.25, 9.86]2.20-8.44 [-9.86, -7.25]8.84 [7.42, 10.29]0% [0%, 0%]0%0%-1.25+0.412026-08-05 → 2026-08-29
tmax00Zbilinear365d31 1 QC8.46 [7.47, 9.72]2.25-8.46 [-9.72, -7.47]8.88 [7.77, 10.12]0% [0%, 0%]0%0%-0.39+0.632026-01-05 → 2026-08-29
tmax00Zbilinearall31 1 QC8.46 [7.43, 9.63]2.25-8.46 [-9.63, -7.43]8.88 [7.76, 10.02]0% [0%, 0%]0%0%-0.39+0.632026-01-05 → 2026-08-29
tmax00Znearest30d25 1 QC8.63 [7.56, 9.92]2.36-8.63 [-9.92, -7.56]9.07 [7.84, 10.32]0% [0%, 0%]0%0%-1.29+0.372026-08-05 → 2026-08-29
tmax00Znearest90d25 1 QC8.63 [7.36, 10.16]2.36-8.63 [-10.16, -7.36]9.07 [7.57, 10.54]0% [0%, 0%]0%0%-1.29+0.372026-08-05 → 2026-08-29
tmax00Znearest365d31 1 QC8.65 [7.57, 10.02]2.38-8.65 [-10.02, -7.57]9.10 [7.89, 10.46]0% [0%, 0%]0%0%-0.42+0.612026-01-05 → 2026-08-29
tmax00Znearestall31 1 QC8.65 [7.58, 9.89]2.38-8.65 [-9.89, -7.58]9.10 [7.87, 10.29]0% [0%, 0%]0%0%-0.42+0.612026-01-05 → 2026-08-29
tmax12Zbilinear30d25 1 QC9.70 [8.68, 10.94]1.84-9.70 [-10.94, -8.68]9.95 [8.83, 11.15]0% [0%, 0%]0%0%-1.58+0.512026-08-05 → 2026-08-29
tmax12Zbilinear90d25 1 QC9.70 [8.46, 11.22]1.84-9.70 [-11.22, -8.46]9.95 [8.59, 11.43]0% [0%, 0%]0%0%-1.58+0.512026-08-05 → 2026-08-29
tmax12Zbilinear365d30 1 QC10.00 [8.86, 11.69]2.02-10.00 [-11.69, -8.86]10.28 [9.07, 11.84]0% [0%, 0%]0%0%-0.78+0.632026-01-05 → 2026-08-29
tmax12Zbilinearall30 1 QC10.00 [8.81, 11.41]2.02-10.00 [-11.41, -8.81]10.28 [8.99, 11.62]0% [0%, 0%]0%0%-0.78+0.632026-01-05 → 2026-08-29
tmax12Znearest30d25 1 QC9.86 [8.74, 11.21]2.03-9.86 [-11.21, -8.74]10.14 [8.92, 11.45]0% [0%, 0%]0%0%-1.62+0.462026-08-05 → 2026-08-29
tmax12Znearest90d25 1 QC9.86 [8.55, 11.50]2.03-9.86 [-11.50, -8.55]10.14 [8.70, 11.73]0% [0%, 0%]0%0%-1.62+0.462026-08-05 → 2026-08-29
tmax12Znearest365d30 1 QC10.15 [8.92, 11.87]2.15-10.15 [-11.87, -8.92]10.45 [9.12, 12.07]0% [0%, 0%]0%0%-0.81+0.602026-01-05 → 2026-08-29
tmax12Znearestall30 1 QC10.15 [8.87, 11.58]2.15-10.15 [-11.58, -8.87]10.45 [9.05, 11.85]0% [0%, 0%]0%0%-0.81+0.602026-01-05 → 2026-08-29
tmin00Zbilinear30d25 1 QC3.74 [2.22, 5.94]2.96+2.76 [0.53, 5.37]4.64 [2.69, 6.59]16% [0%, 31%]32%44%+0.14+0.302026-08-05 → 2026-08-29
tmin00Zbilinear90d25 1 QC3.74 [2.13, 6.45]2.96+2.76 [0.21, 6.29]4.64 [2.59, 7.07]16% [0%, 31%]32%44%+0.14+0.302026-08-05 → 2026-08-29
tmin00Zbilinear365d31 1 QC4.40 [2.40, 6.63]3.33+3.62 [0.85, 6.47]5.70 [2.85, 7.89]13% [0%, 27%]29%45%+0.12+0.332026-01-05 → 2026-08-29
tmin00Zbilinearall31 1 QC4.40 [2.53, 7.01]3.33+3.62 [1.03, 6.97]5.70 [3.01, 8.06]13% [0%, 26%]29%45%+0.12+0.332026-01-05 → 2026-08-29
tmin00Znearest30d25 1 QC3.70 [2.19, 5.88]2.97+2.67 [0.39, 5.25]4.61 [2.64, 6.56]16% [0%, 31%]32%48%+0.15+0.302026-08-05 → 2026-08-29
tmin00Znearest90d25 1 QC3.70 [2.09, 6.38]2.97+2.67 [0.03, 6.01]4.61 [2.55, 6.96]16% [0%, 31%]32%48%+0.15+0.302026-08-05 → 2026-08-29
tmin00Znearest365d31 1 QC4.36 [2.37, 6.56]3.34+3.53 [0.71, 6.37]5.65 [2.83, 7.83]13% [0%, 27%]29%48%+0.13+0.322026-01-05 → 2026-08-29
tmin00Znearestall31 1 QC4.36 [2.48, 6.92]3.34+3.53 [0.91, 6.88]5.65 [2.95, 8.00]13% [0%, 26%]29%48%+0.13+0.322026-01-05 → 2026-08-29
tmin12Zbilinear30d25 1 QC3.44 [1.99, 5.44]3.15+1.94 [-0.45, 4.61]4.34 [2.52, 6.16]28% [0%, 52%]36%40%+0.21+0.262026-08-05 → 2026-08-29
tmin12Zbilinear90d25 1 QC3.44 [1.89, 5.87]3.15+1.94 [-0.75, 5.69]4.34 [2.37, 6.56]28% [0%, 54%]36%40%+0.21+0.262026-08-05 → 2026-08-29
tmin12Zbilinear365d30 1 QC4.05 [2.17, 6.31]3.44+2.80 [-0.10, 5.98]5.30 [2.67, 7.52]23% [0%, 47%]33%40%+0.18+0.282026-01-05 → 2026-08-29
tmin12Zbilinearall30 1 QC4.05 [2.31, 6.67]3.44+2.80 [0.09, 6.45]5.30 [2.83, 7.84]23% [0%, 49%]33%40%+0.18+0.282026-01-05 → 2026-08-29
tmin12Znearest30d25 1 QC3.44 [1.99, 5.46]3.20+1.89 [-0.59, 4.63]4.37 [2.49, 6.21]28% [0%, 52%]36%40%+0.21+0.252026-08-05 → 2026-08-29
tmin12Znearest90d25 1 QC3.44 [1.85, 5.91]3.20+1.89 [-0.92, 5.64]4.37 [2.36, 6.62]28% [0%, 54%]36%40%+0.21+0.252026-08-05 → 2026-08-29
tmin12Znearest365d30 1 QC4.03 [2.17, 6.26]3.47+2.74 [-0.22, 5.99]5.28 [2.64, 7.47]23% [0%, 47%]33%40%+0.18+0.272026-01-05 → 2026-08-29
tmin12Znearestall30 1 QC4.03 [2.27, 6.62]3.47+2.74 [-0.04, 6.48]5.28 [2.79, 7.79]23% [0%, 49%]33%40%+0.18+0.272026-01-05 → 2026-08-29

+ 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 GraphCast (IFS init) at KOKC, lead day 4, 00Z bilinear tmax+20+100-10-202026-08-05: -7.34 °F2026-08-06: -5.86 °F2026-08-07: -9.44 °F2026-08-08: -6.36 °F2026-08-09: -5.67 °F2026-08-10: -7.19 °F2026-08-11: -5.95 °F2026-08-12: -7.76 °F2026-08-13: -8.92 °F2026-08-14: -10.79 °F2026-08-15: -8.15 °F2026-08-16: -6.59 °F2026-08-17: -10.52 °F2026-08-18: -13.11 °F2026-08-19: -6.82 °F2026-08-20: -10.42 °F2026-08-21: -3.41 °F2026-08-22: -9.84 °F2026-08-23: -4.74 °F2026-08-24: -9.07 °F2026-08-25: -11.97 °F2026-08-26: -6.42 °F2026-08-27: -8.6 °F2026-08-28: -13.89 °F2026-08-29: -12.21 °F2026-08-052026-08-29°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
2026-08-29-12.21
2026-08-28-13.89
2026-08-27-8.60
2026-08-26-6.42
2026-08-25-11.97
2026-08-24-9.07
2026-08-23-4.74
2026-08-22-9.84
2026-08-21-3.41
2026-08-20-10.42
2026-08-19-6.82
2026-08-18-13.11
2026-08-17-10.52
2026-08-16-6.59
2026-08-15-8.15
2026-08-14-10.79
2026-08-13-8.92
2026-08-12-7.76
2026-08-11-5.95
2026-08-10-7.19
2026-08-09-5.67
2026-08-08-6.36
2026-08-07-9.44
2026-08-06-5.86
2026-08-05-7.34

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KOKC, lead day 4-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 4 days-12 to -10 °F: 5 days-10 to -8 °F: 8 days-8 to -6 °F: 7 days-6 to -4 °F: 6 days-4 to -2 °F: 1 day-2 to 0 °F: 0 days0 to 2 °F: 0 days2 to 4 °F: 0 days4 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| 8.23 · P90 |e| 12.21 °F-200+20 °Fn = 31 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
-16.00-14.000
-14.00-12.004
-12.00-10.005
-10.00-8.008
-8.00-6.007
-6.00-4.006
-4.00-2.001
-2.00+0.000
+0.00+2.000
+2.00+4.000
+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
2026-08258.44 -8.44
2026-0168.53 -8.53

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-05 → 2026-08-29 31
GraphCast (IFS init)2026-01-05 → 2026-08-29 31
GraphCast (IFS init)2026-01-05 → 2026-08-29 30
GraphCast (IFS init)2026-01-05 → 2026-08-29 30

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 25 +4.56 [1.90, 6.17] yes
NCEP GFS 25 +5.43 [3.78, 7.41] yes
ECMWF IFS HRES 19 +5.27 [4.53, 6.31] yes
Persistence (baseline) 25 +4.68 [2.89, 6.22] yes

Cite this page

ShortCastCheck, KOKC graphcast_ifs lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KOKC/model/graphcast_ifs/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KOKC (Oklahoma City), model graphcast_ifs, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KOKC/model/graphcast_ifs/lead/4/

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