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

Houston Bush · GraphCast (IFS init) · lead day 9

KIAH · graphcast_ifs · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d21 1 QC6.38 [4.25, 8.19]2.29-6.15 [-8.17, -3.49]6.85 [4.54, 8.42]0% [0%, 0%]5%10%-0.91+0.262026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC6.38 [3.71, 8.27]2.29-6.15 [-8.25, -2.57]6.85 [3.92, 8.50]0% [0%, 0%]5%10%-0.91+0.262026-08-10 → 2026-08-30
tmax00Zbilinear365d27 1 QC6.81 [4.77, 8.57]4.28-4.71 [-7.59, -0.45]7.45 [5.23, 9.06]4% [0%, 13%]7%11%-0.18+0.292026-01-10 → 2026-08-30
tmax00Zbilinearall27 1 QC6.81 [4.88, 8.67]4.28-4.71 [-7.48, -0.26]7.45 [5.32, 9.10]4% [0%, 14%]7%11%-0.18+0.292026-01-10 → 2026-08-30
tmax00Znearest30d21 1 QC6.54 [4.41, 8.33]2.21-6.37 [-8.33, -3.82]7.00 [4.73, 8.55]0% [0%, 0%]10%10%-0.96+0.282026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC6.54 [3.83, 8.42]2.21-6.37 [-8.41, -2.93]7.00 [4.06, 8.63]0% [0%, 0%]10%10%-0.96+0.282026-08-10 → 2026-08-30
tmax00Znearest365d27 1 QC6.93 [4.89, 8.62]4.24-4.89 [-7.74, -0.55]7.56 [5.39, 9.12]4% [0%, 13%]11%11%-0.20+0.302026-01-10 → 2026-08-30
tmax00Znearestall27 1 QC6.93 [5.04, 8.72]4.24-4.89 [-7.64, -0.34]7.56 [5.48, 9.15]4% [0%, 14%]11%11%-0.20+0.302026-01-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC6.72 [4.10, 8.79]2.44-6.72 [-8.79, -4.10]7.35 [4.69, 9.08]5% [0%, 19%]10%10%-1.01+0.212026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC6.72 [3.18, 8.89]2.44-6.72 [-8.89, -3.18]7.35 [3.64, 9.18]5% [0%, 25%]10%10%-1.01+0.212026-08-10 → 2026-08-30
tmax12Zbilinear365d26 1 QC6.45 [3.98, 8.47]3.34-5.90 [-8.27, -2.56]7.31 [4.69, 8.95]12% [0%, 36%]15%15%-0.25+0.372026-01-10 → 2026-08-30
tmax12Zbilinearall26 1 QC6.45 [4.06, 8.50]3.34-5.90 [-8.30, -2.64]7.31 [5.08, 8.97]12% [0%, 33%]15%15%-0.25+0.372026-01-10 → 2026-08-30
tmax12Znearest30d21 1 QC6.91 [4.39, 8.94]2.36-6.91 [-8.94, -4.39]7.50 [4.92, 9.20]5% [0%, 19%]10%10%-1.07+0.232026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC6.91 [3.52, 9.03]2.36-6.91 [-9.03, -3.52]7.50 [3.92, 9.30]5% [0%, 25%]10%10%-1.07+0.232026-08-10 → 2026-08-30
tmax12Znearest365d26 1 QC6.62 [4.20, 8.60]3.32-6.06 [-8.42, -2.75]7.44 [4.92, 9.07]12% [0%, 36%]15%15%-0.29+0.382026-01-10 → 2026-08-30
tmax12Znearestall26 1 QC6.62 [4.30, 8.63]3.32-6.06 [-8.43, -2.71]7.44 [5.24, 9.08]12% [0%, 33%]15%15%-0.29+0.382026-01-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC3.27 [2.73, 3.90]3.19+0.60 [-1.75, 3.40]3.74 [3.26, 4.28]14% [4%, 27%]29%43%+0.15+0.162026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC3.27 [2.73, 4.05]3.19+0.60 [-1.95, 3.79]3.74 [3.24, 4.39]14% [0%, 29%]29%43%+0.15+0.162026-08-10 → 2026-08-30
tmin00Zbilinear365d27 1 QC4.25 [2.94, 6.81]4.14+1.62 [-1.08, 5.05]5.87 [3.43, 9.63]11% [0%, 23%]26%37%+0.27+0.312026-01-10 → 2026-08-30
tmin00Zbilinearall27 1 QC4.25 [2.96, 7.14]4.14+1.62 [-1.16, 5.18]5.87 [3.46, 9.72]11% [0%, 25%]26%37%+0.27+0.312026-01-10 → 2026-08-30
tmin00Znearest30d21 1 QC3.25 [2.70, 3.88]3.18+0.56 [-1.79, 3.37]3.73 [3.27, 4.25]14% [4%, 27%]33%43%+0.16+0.162026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC3.25 [2.69, 3.98]3.18+0.56 [-1.99, 3.74]3.73 [3.24, 4.34]14% [0%, 29%]33%43%+0.16+0.162026-08-10 → 2026-08-30
tmin00Znearest365d27 1 QC4.24 [2.91, 6.84]4.15+1.60 [-1.08, 5.07]5.88 [3.44, 9.66]11% [0%, 23%]30%37%+0.27+0.312026-01-10 → 2026-08-30
tmin00Znearestall27 1 QC4.24 [2.94, 7.17]4.15+1.60 [-1.17, 5.24]5.88 [3.46, 9.78]11% [0%, 25%]30%37%+0.27+0.312026-01-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC3.05 [2.49, 3.56]3.06+0.32 [-1.92, 2.90]3.62 [3.11, 4.04]24% [8%, 40%]38%38%+0.21+0.192026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC3.05 [2.48, 3.64]3.06+0.32 [-2.07, 3.34]3.62 [3.16, 4.07]24% [5%, 41%]38%38%+0.21+0.192026-08-10 → 2026-08-30
tmin12Zbilinear365d26 1 QC3.26 [2.69, 3.99]3.25+0.44 [-1.56, 2.77]3.80 [3.25, 4.45]19% [0%, 35%]31%42%+0.36+0.372026-01-10 → 2026-08-30
tmin12Zbilinearall26 1 QC3.26 [2.64, 4.04]3.25+0.44 [-1.79, 2.60]3.80 [3.24, 4.48]19% [0%, 36%]31%42%+0.36+0.372026-01-10 → 2026-08-30
tmin12Znearest30d21 1 QC3.07 [2.52, 3.56]3.08+0.27 [-1.96, 2.86]3.61 [3.11, 4.02]24% [8%, 40%]38%38%+0.21+0.192026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC3.07 [2.49, 3.64]3.08+0.27 [-2.11, 3.29]3.61 [3.15, 4.06]24% [5%, 41%]38%38%+0.21+0.192026-08-10 → 2026-08-30
tmin12Znearest365d26 1 QC3.28 [2.71, 4.03]3.28+0.40 [-1.59, 2.75]3.81 [3.26, 4.48]19% [0%, 35%]31%42%+0.36+0.372026-01-10 → 2026-08-30
tmin12Znearestall26 1 QC3.28 [2.68, 4.09]3.28+0.40 [-1.81, 2.57]3.81 [3.24, 4.53]19% [0%, 36%]31%42%+0.36+0.372026-01-10 → 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 KIAH, lead day 9, 00Z bilinear tmax+20+100-10-202026-08-10: +2.46 °F2026-08-11: -4.3 °F2026-08-12: -4.3 °F2026-08-13: -3.71 °F2026-08-14: -1.66 °F2026-08-15: -5.79 °F2026-08-16: -6.42 °F2026-08-17: -7.35 °F2026-08-18: -7.34 °F2026-08-19: -7.05 °F2026-08-20: -8.29 °F2026-08-21: -10.04 °F2026-08-22: -11.33 °F2026-08-23: -9.21 °F2026-08-24: -8.64 °F2026-08-25: -7.62 °F2026-08-26: -8.28 °F2026-08-27: -6.15 °F2026-08-28: -3.25 °F2026-08-29: -6.31 °F2026-08-30: -4.53 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-4.53
2026-08-29-6.31
2026-08-28-3.25
2026-08-27-6.15
2026-08-26-8.28
2026-08-25-7.62
2026-08-24-8.64
2026-08-23-9.21
2026-08-22-11.33
2026-08-21-10.04
2026-08-20-8.29
2026-08-19-7.05
2026-08-18-7.34
2026-08-17-7.35
2026-08-16-6.42
2026-08-15-5.79
2026-08-14-1.66
2026-08-13-3.71
2026-08-12-4.30
2026-08-11-4.30
2026-08-10+2.46

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KIAH, lead day 9-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 2 days-10 to -8 °F: 5 days-8 to -6 °F: 7 days-6 to -4 °F: 4 days-4 to -2 °F: 2 days-2 to 0 °F: 2 days0 to 2 °F: 0 days2 to 4 °F: 1 day4 to 6 °F: 0 days6 to 8 °F: 1 day8 to 10 °F: 1 day10 to 12 °F: 1 day12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 7.05 · P90 |e| 10.52 °F-200+20 °Fn = 27 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
-14.00-12.001
-12.00-10.002
-10.00-8.005
-8.00-6.007
-6.00-4.004
-4.00-2.002
-2.00+0.002
+0.00+2.000
+2.00+4.001
+4.00+6.000
+6.00+8.001
+8.00+10.001
+10.00+12.001
+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
2026-08216.38 -6.15
2026-0168.31 +0.33

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 26
GraphCast (IFS init)2026-01-10 → 2026-08-30 26

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 21 +2.62 [1.51, 3.52] yes
NCEP GFS 21 +3.51 [0.65, 5.41] yes
ECMWF IFS HRES 16 +3.30 [-0.22, 4.10] no
Persistence (baseline) 21 +3.05 [0.39, 4.66] yes

Cite this page

ShortCastCheck, KIAH graphcast_ifs lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KIAH/model/graphcast_ifs/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KIAH (Houston Bush), model graphcast_ifs, lead day 9. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KIAH/model/graphcast_ifs/lead/9/

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