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

Oklahoma City · GraphCast (IFS init) · lead day 8

KOKC · graphcast_ifs · lead 8

Target day = initialization date + 8 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, 2 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 2 QC10.73 [9.14, 12.20]3.64-10.66 [-12.19, -9.00]11.64 [10.26, 12.98]5% [0%, 14%]5%9%-1.03+0.292026-08-09 → 2026-08-30
tmax00Zbilinear90d22 2 QC10.73 [8.93, 12.42]3.64-10.66 [-12.38, -8.81]11.64 [9.95, 13.09]5% [0%, 14%]5%9%-1.03+0.292026-08-09 → 2026-08-30
tmax00Zbilinear365d28 2 QC10.28 [8.48, 11.83]4.44-9.59 [-11.62, -6.77]11.22 [9.45, 12.48]4% [0%, 11%]4%11%-0.66+0.292026-01-09 → 2026-08-30
tmax00Zbilinearall28 2 QC10.28 [8.41, 11.80]4.44-9.59 [-11.51, -6.67]11.22 [9.45, 12.50]4% [0%, 11%]4%11%-0.66+0.292026-01-09 → 2026-08-30
tmax00Znearest30d22 2 QC10.95 [9.23, 12.58]3.81-10.85 [-12.58, -9.06]11.88 [10.36, 13.29]0% [0%, 0%]5%5%-1.08+0.252026-08-09 → 2026-08-30
tmax00Znearest90d22 2 QC10.95 [8.99, 12.71]3.81-10.85 [-12.70, -8.80]11.88 [9.91, 13.39]0% [0%, 0%]5%5%-1.08+0.252026-08-09 → 2026-08-30
tmax00Znearest365d28 2 QC10.51 [8.58, 12.15]4.54-9.85 [-11.92, -6.90]11.47 [9.50, 12.78]0% [0%, 0%]4%7%-0.70+0.282026-01-09 → 2026-08-30
tmax00Znearestall28 2 QC10.51 [8.59, 12.15]4.54-9.85 [-11.83, -6.95]11.47 [9.62, 12.86]0% [0%, 0%]4%7%-0.70+0.282026-01-09 → 2026-08-30
tmax12Zbilinear30d22 2 QC11.01 [9.58, 12.65]4.04-10.97 [-12.65, -9.49]12.04 [10.53, 13.53]5% [0%, 14%]5%5%-1.09+0.212026-08-09 → 2026-08-30
tmax12Zbilinear90d22 2 QC11.01 [9.56, 12.99]4.04-10.97 [-12.99, -9.49]12.04 [10.38, 13.88]5% [0%, 14%]5%5%-1.09+0.212026-08-09 → 2026-08-30
tmax12Zbilinear365d27 2 QC10.75 [9.24, 12.36]4.03-10.71 [-12.29, -9.21]11.75 [10.18, 13.36]4% [0%, 11%]4%4%-0.86+0.312026-01-09 → 2026-08-30
tmax12Zbilinearall27 2 QC10.75 [9.28, 12.25]4.03-10.71 [-12.25, -9.20]11.75 [10.12, 13.20]4% [0%, 11%]4%4%-0.86+0.312026-01-09 → 2026-08-30
tmax12Znearest30d22 2 QC11.18 [9.66, 12.88]4.19-11.14 [-12.87, -9.55]12.25 [10.64, 13.82]5% [0%, 14%]5%5%-1.12+0.182026-08-09 → 2026-08-30
tmax12Znearest90d22 2 QC11.18 [9.65, 13.26]4.19-11.14 [-13.26, -9.58]12.25 [10.45, 14.20]5% [0%, 14%]5%5%-1.12+0.182026-08-09 → 2026-08-30
tmax12Znearest365d27 2 QC10.96 [9.44, 12.62]4.14-10.92 [-12.61, -9.36]12.00 [10.28, 13.64]4% [0%, 11%]4%4%-0.90+0.292026-01-09 → 2026-08-30
tmax12Znearestall27 2 QC10.96 [9.40, 12.57]4.14-10.92 [-12.57, -9.34]12.00 [10.25, 13.52]4% [0%, 11%]4%4%-0.90+0.292026-01-09 → 2026-08-30
tmin00Zbilinear30d22 2 QC2.54 [2.09, 3.27]2.32+1.41 [0.45, 2.61]3.27 [2.56, 4.42]32% [19%, 42%]50%68%+0.49+0.522026-08-09 → 2026-08-30
tmin00Zbilinear90d22 2 QC2.54 [2.05, 3.42]2.32+1.41 [0.26, 2.90]3.27 [2.48, 4.69]32% [18%, 43%]50%68%+0.49+0.522026-08-09 → 2026-08-30
tmin00Zbilinear365d28 2 QC3.24 [2.35, 5.02]2.79+2.36 [0.86, 4.68]4.46 [2.80, 6.55]25% [5%, 38%]46%64%+0.38+0.472026-01-09 → 2026-08-30
tmin00Zbilinearall28 2 QC3.24 [2.30, 5.24]2.79+2.36 [0.97, 4.71]4.46 [2.85, 6.68]25% [0%, 38%]46%64%+0.38+0.472026-01-09 → 2026-08-30
tmin00Znearest30d22 2 QC2.52 [2.04, 3.25]2.37+1.32 [0.42, 2.49]3.26 [2.54, 4.43]27% [14%, 40%]50%68%+0.49+0.512026-08-09 → 2026-08-30
tmin00Znearest90d22 2 QC2.52 [2.00, 3.44]2.37+1.32 [0.21, 2.79]3.26 [2.49, 4.67]27% [12%, 43%]50%68%+0.49+0.512026-08-09 → 2026-08-30
tmin00Znearest365d28 2 QC3.21 [2.30, 4.97]2.82+2.27 [0.78, 4.58]4.44 [2.80, 6.54]21% [5%, 35%]46%64%+0.39+0.462026-01-09 → 2026-08-30
tmin00Znearestall28 2 QC3.21 [2.24, 5.15]2.82+2.27 [0.90, 4.60]4.44 [2.80, 6.66]21% [0%, 35%]46%64%+0.39+0.462026-01-09 → 2026-08-30
tmin12Zbilinear30d22 2 QC2.77 [2.25, 3.37]2.60+0.66 [-0.62, 1.96]3.36 [2.92, 3.83]23% [5%, 36%]45%55%+0.44+0.472026-08-09 → 2026-08-30
tmin12Zbilinear90d22 2 QC2.77 [2.20, 3.50]2.60+0.66 [-0.93, 2.25]3.36 [2.82, 3.93]23% [0%, 38%]45%55%+0.44+0.472026-08-09 → 2026-08-30
tmin12Zbilinear365d27 2 QC2.74 [2.16, 3.33]2.47+0.93 [-0.35, 2.26]3.33 [2.75, 3.84]19% [0%, 33%]48%59%+0.47+0.522026-01-09 → 2026-08-30
tmin12Zbilinearall27 2 QC2.74 [2.22, 3.34]2.47+0.93 [-0.36, 2.27]3.33 [2.80, 3.84]19% [0%, 32%]48%59%+0.47+0.522026-01-09 → 2026-08-30
tmin12Znearest30d22 2 QC2.78 [2.24, 3.38]2.64+0.61 [-0.66, 1.89]3.41 [2.96, 3.90]23% [5%, 36%]45%55%+0.44+0.462026-08-09 → 2026-08-30
tmin12Znearest90d22 2 QC2.78 [2.15, 3.51]2.64+0.61 [-1.00, 2.16]3.41 [2.86, 4.00]23% [0%, 38%]45%55%+0.44+0.462026-08-09 → 2026-08-30
tmin12Znearest365d27 2 QC2.76 [2.17, 3.35]2.50+0.91 [-0.39, 2.24]3.37 [2.79, 3.88]19% [0%, 33%]48%59%+0.46+0.522026-01-09 → 2026-08-30
tmin12Znearestall27 2 QC2.76 [2.24, 3.37]2.50+0.91 [-0.41, 2.25]3.37 [2.85, 3.88]19% [0%, 32%]48%59%+0.46+0.522026-01-09 → 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 GraphCast (IFS init) at KOKC, lead day 8, 00Z bilinear tmax+20+100-10-202026-08-09: -8.13 °F2026-08-10: -11.48 °F2026-08-11: -6.97 °F2026-08-12: -18.69 °F2026-08-13: -12.5 °F2026-08-14: -7.52 °F2026-08-15: -12.97 °F2026-08-16: -11.9 °F2026-08-17: -11.02 °F2026-08-18: -14.44 °F2026-08-19: -11.66 °F2026-08-20: -13.48 °F2026-08-21: -5.05 °F2026-08-22: -9.11 °F2026-08-23: -6.37 °F2026-08-24: -13.55 °F2026-08-25: -10.6 °F2026-08-26: +0.71 °F2026-08-27: -2.9 °F2026-08-28: -19.45 °F2026-08-29: -15.25 °F2026-08-30: -12.23 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-12.23
2026-08-29-15.25
2026-08-28-19.45
2026-08-27-2.90
2026-08-26+0.71
2026-08-25-10.60
2026-08-24-13.55
2026-08-23-6.37
2026-08-22-9.11
2026-08-21-5.05
2026-08-20-13.48
2026-08-19-11.66
2026-08-18-14.44
2026-08-17-11.02
2026-08-16-11.90
2026-08-15-12.97
2026-08-14-7.52
2026-08-13-12.50
2026-08-12-18.69
2026-08-11-6.97
2026-08-10-11.48
2026-08-09-8.13

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KOKC, lead day 8-20 to -18 °F: 2 days-18 to -16 °F: 0 days-16 to -14 °F: 2 days-14 to -12 °F: 6 days-12 to -10 °F: 7 days-10 to -8 °F: 2 days-8 to -6 °F: 3 days-6 to -4 °F: 2 days-4 to -2 °F: 2 days-2 to 0 °F: 0 days0 to 2 °F: 1 day2 to 4 °F: 0 days4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 1 day10 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| 11.25 · P90 |e| 14.68 °F-200+20 °Fn = 28 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
-20.00-18.002
-18.00-16.000
-16.00-14.002
-14.00-12.006
-12.00-10.007
-10.00-8.002
-8.00-6.003
-6.00-4.002
-4.00-2.002
-2.00+0.000
+0.00+2.001
+2.00+4.000
+4.00+6.000
+6.00+8.000
+8.00+10.001
+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
2026-082210.73 -10.66
2026-0168.64 -5.65

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 27
GraphCast (IFS init)2026-01-09 → 2026-08-30 27

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 22 +3.86 [1.86, 5.90] yes
NCEP GFS 22 +6.63 [5.21, 8.60] yes
ECMWF IFS HRES 17 +7.67 [5.73, 11.45] yes
Persistence (baseline) 22 +5.45 [1.60, 8.06] yes

Cite this page

ShortCastCheck, KOKC graphcast_ifs lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KOKC/model/graphcast_ifs/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KOKC (Oklahoma City), model graphcast_ifs, lead day 8. 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/8/

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