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

Oklahoma City · GraphCast (IFS init) · lead day 6

KOKC · graphcast_ifs · 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, 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
tmax00Zbilinear30d24 2 QC9.44 [8.35, 10.52]3.22-9.44 [-10.52, -8.35]10.22 [9.31, 11.19]0% [0%, 0%]4%4%-1.67+0.102026-08-07 → 2026-08-30
tmax00Zbilinear90d24 2 QC9.44 [8.10, 10.77]3.22-9.44 [-10.77, -8.10]10.22 [9.29, 11.38]0% [0%, 0%]4%4%-1.67+0.102026-08-07 → 2026-08-30
tmax00Zbilinear365d30 2 QC9.64 [8.72, 10.71]3.26-9.64 [-10.71, -8.72]10.40 [9.57, 11.48]0% [0%, 0%]3%3%-1.04+0.322026-01-07 → 2026-08-30
tmax00Zbilinearall30 2 QC9.64 [8.56, 10.76]3.26-9.64 [-10.76, -8.56]10.40 [9.53, 11.38]0% [0%, 0%]3%3%-1.04+0.322026-01-07 → 2026-08-30
tmax00Znearest30d24 2 QC9.68 [8.53, 10.81]3.30-9.68 [-10.81, -8.53]10.47 [9.52, 11.45]0% [0%, 0%]4%4%-1.73+0.082026-08-07 → 2026-08-30
tmax00Znearest90d24 2 QC9.68 [8.23, 11.07]3.30-9.68 [-11.07, -8.23]10.47 [9.48, 11.65]0% [0%, 0%]4%4%-1.73+0.082026-08-07 → 2026-08-30
tmax00Znearest365d30 2 QC9.88 [8.90, 11.02]3.29-9.88 [-11.02, -8.90]10.65 [9.80, 11.73]0% [0%, 0%]3%3%-1.09+0.312026-01-07 → 2026-08-30
tmax00Znearestall30 2 QC9.88 [8.74, 11.02]3.29-9.88 [-11.02, -8.74]10.65 [9.75, 11.64]0% [0%, 0%]3%3%-1.09+0.312026-01-07 → 2026-08-30
tmax12Zbilinear30d24 2 QC10.37 [9.03, 12.07]3.26-10.37 [-12.07, -9.03]11.06 [9.52, 12.62]0% [0%, 0%]0%0%-1.93+0.092026-08-07 → 2026-08-30
tmax12Zbilinear90d24 2 QC10.37 [8.93, 12.62]3.26-10.37 [-12.62, -8.93]11.06 [9.46, 13.02]0% [0%, 0%]0%0%-1.93+0.092026-08-07 → 2026-08-30
tmax12Zbilinear365d29 2 QC9.86 [8.33, 11.67]3.48-9.67 [-11.62, -7.85]10.62 [8.99, 12.33]0% [0%, 0%]0%3%-1.09+0.262026-01-07 → 2026-08-30
tmax12Zbilinearall29 2 QC9.86 [8.18, 11.59]3.48-9.67 [-11.56, -7.61]10.62 [8.84, 12.22]0% [0%, 0%]0%3%-1.09+0.262026-01-07 → 2026-08-30
tmax12Znearest30d24 2 QC10.58 [9.14, 12.37]3.41-10.58 [-12.37, -9.14]11.30 [9.68, 12.93]0% [0%, 0%]0%0%-1.99+0.052026-08-07 → 2026-08-30
tmax12Znearest90d24 2 QC10.58 [9.03, 13.00]3.41-10.58 [-13.00, -9.03]11.30 [9.60, 13.30]0% [0%, 0%]0%0%-1.99+0.052026-08-07 → 2026-08-30
tmax12Znearest365d29 2 QC10.06 [8.47, 11.94]3.60-9.86 [-11.94, -7.99]10.84 [9.12, 12.61]0% [0%, 0%]0%3%-1.13+0.242026-01-07 → 2026-08-30
tmax12Znearestall29 2 QC10.06 [8.28, 11.89]3.60-9.86 [-11.86, -7.76]10.84 [8.96, 12.51]0% [0%, 0%]0%3%-1.13+0.242026-01-07 → 2026-08-30
tmin00Zbilinear30d24 2 QC3.53 [2.58, 4.88]3.14+2.15 [0.36, 4.20]4.24 [3.14, 5.57]4% [0%, 12%]33%46%+0.10+0.212026-08-07 → 2026-08-30
tmin00Zbilinear90d24 2 QC3.53 [2.46, 5.42]3.14+2.15 [-0.08, 4.93]4.24 [3.02, 6.02]4% [0%, 12%]33%46%+0.10+0.212026-08-07 → 2026-08-30
tmin00Zbilinear365d30 2 QC4.02 [2.79, 5.59]3.40+2.72 [0.83, 4.90]5.11 [3.40, 6.97]3% [0%, 10%]27%47%+0.06+0.202026-01-07 → 2026-08-30
tmin00Zbilinearall30 2 QC4.02 [2.83, 5.85]3.40+2.72 [0.73, 5.08]5.11 [3.43, 7.31]3% [0%, 9%]27%47%+0.06+0.202026-01-07 → 2026-08-30
tmin00Znearest30d24 2 QC3.57 [2.64, 4.88]3.21+2.08 [0.23, 4.17]4.26 [3.21, 5.58]8% [0%, 21%]33%46%+0.09+0.202026-08-07 → 2026-08-30
tmin00Znearest90d24 2 QC3.57 [2.52, 5.42]3.21+2.08 [-0.19, 4.91]4.26 [3.06, 6.01]8% [0%, 22%]33%46%+0.09+0.202026-08-07 → 2026-08-30
tmin00Znearest365d30 2 QC4.07 [2.85, 5.70]3.48+2.67 [0.74, 4.91]5.15 [3.45, 7.01]7% [0%, 18%]27%43%+0.05+0.182026-01-07 → 2026-08-30
tmin00Znearestall30 2 QC4.07 [2.89, 5.93]3.48+2.67 [0.63, 5.06]5.15 [3.51, 7.35]7% [0%, 17%]27%43%+0.05+0.182026-01-07 → 2026-08-30
tmin12Zbilinear30d24 2 QC3.10 [2.24, 4.24]3.01+1.68 [-0.28, 3.74]3.78 [2.90, 4.74]25% [8%, 42%]38%50%+0.21+0.252026-08-07 → 2026-08-30
tmin12Zbilinear90d24 2 QC3.10 [2.15, 4.63]3.01+1.68 [-0.75, 4.38]3.78 [2.78, 5.00]25% [5%, 44%]38%50%+0.21+0.252026-08-07 → 2026-08-30
tmin12Zbilinear365d29 2 QC3.78 [2.32, 5.97]3.60+2.61 [0.06, 5.56]5.18 [3.01, 7.85]24% [8%, 41%]38%48%+0.06+0.102026-01-07 → 2026-08-30
tmin12Zbilinearall29 2 QC3.78 [2.40, 6.10]3.60+2.61 [0.18, 5.76]5.18 [3.03, 8.16]24% [9%, 42%]38%48%+0.06+0.102026-01-07 → 2026-08-30
tmin12Znearest30d24 2 QC3.13 [2.30, 4.25]3.04+1.62 [-0.41, 3.67]3.78 [2.92, 4.72]21% [7%, 36%]38%50%+0.20+0.242026-08-07 → 2026-08-30
tmin12Znearest90d24 2 QC3.13 [2.19, 4.54]3.04+1.62 [-0.85, 4.29]3.78 [2.79, 4.94]21% [5%, 38%]38%50%+0.20+0.242026-08-07 → 2026-08-30
tmin12Znearest365d29 2 QC3.82 [2.38, 5.96]3.63+2.55 [-0.06, 5.52]5.19 [3.03, 7.88]21% [7%, 35%]38%48%+0.05+0.092026-01-07 → 2026-08-30
tmin12Znearestall29 2 QC3.82 [2.44, 6.16]3.63+2.55 [0.05, 5.72]5.19 [3.06, 8.18]21% [8%, 36%]38%48%+0.05+0.092026-01-07 → 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 GraphCast (IFS init) at KOKC, lead day 6, 00Z bilinear tmax+20+100-10-202026-08-07: -1.65 °F2026-08-08: -17.7 °F2026-08-09: -8.17 °F2026-08-10: -5.87 °F2026-08-11: -5.91 °F2026-08-12: -5.96 °F2026-08-13: -9.8 °F2026-08-14: -17.81 °F2026-08-15: -8.75 °F2026-08-16: -7.54 °F2026-08-17: -7.79 °F2026-08-18: -11.26 °F2026-08-19: -6.62 °F2026-08-20: -12.16 °F2026-08-21: -10.42 °F2026-08-22: -5.07 °F2026-08-23: -5.8 °F2026-08-24: -13.73 °F2026-08-25: -11.75 °F2026-08-26: -6.21 °F2026-08-27: -8.74 °F2026-08-28: -13.23 °F2026-08-29: -13.45 °F2026-08-30: -11.24 °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
2026-08-30-11.24
2026-08-29-13.45
2026-08-28-13.23
2026-08-27-8.74
2026-08-26-6.21
2026-08-25-11.75
2026-08-24-13.73
2026-08-23-5.80
2026-08-22-5.07
2026-08-21-10.42
2026-08-20-12.16
2026-08-19-6.62
2026-08-18-11.26
2026-08-17-7.79
2026-08-16-7.54
2026-08-15-8.75
2026-08-14-17.81
2026-08-13-9.80
2026-08-12-5.96
2026-08-11-5.91
2026-08-10-5.87
2026-08-09-8.17
2026-08-08-17.70
2026-08-07-1.65

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KOKC, lead day 6-20 to -18 °F: 0 days-18 to -16 °F: 3 days-16 to -14 °F: 0 days-14 to -12 °F: 5 days-12 to -10 °F: 6 days-10 to -8 °F: 4 days-8 to -6 °F: 5 days-6 to -4 °F: 6 days-4 to -2 °F: 0 days-2 to 0 °F: 1 day0 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| 9.28 · P90 |e| 14.02 °F-200+20 °Fn = 30 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
-18.00-16.003
-16.00-14.000
-14.00-12.005
-12.00-10.006
-10.00-8.004
-8.00-6.005
-6.00-4.006
-4.00-2.000
-2.00+0.001
+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
2026-08249.44 -9.44
2026-01610.42 -10.42

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 29
GraphCast (IFS init)2026-01-07 → 2026-08-30 29

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 24 +4.91 [2.99, 6.42] yes
NCEP GFS 24 +5.22 [3.72, 7.30] yes
ECMWF IFS HRES 19 +6.79 [1.89, 8.07] yes
Persistence (baseline) 24 +5.90 [3.85, 7.35] yes

Cite this page

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

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