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

Houston Bush · GraphCast (IFS init) · lead day 6

KIAH · 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, 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
tmax00Zbilinear30d24 1 QC6.29 [4.54, 8.08]2.27-6.29 [-8.08, -4.54]6.81 [4.88, 8.39]0% [0%, 0%]8%12%-0.96+0.292026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC6.29 [4.38, 8.22]2.27-6.29 [-8.22, -4.38]6.81 [4.62, 8.50]0% [0%, 0%]8%12%-0.96+0.292026-08-07 → 2026-08-30
tmax00Zbilinear365d30 1 QC6.71 [4.98, 8.50]2.32-6.71 [-8.50, -4.98]7.24 [5.48, 8.75]0% [0%, 0%]7%10%-0.56+0.482026-01-07 → 2026-08-30
tmax00Zbilinearall30 1 QC6.71 [4.96, 8.44]2.32-6.71 [-8.44, -4.96]7.24 [5.43, 8.74]0% [0%, 0%]7%10%-0.56+0.482026-01-07 → 2026-08-30
tmax00Znearest30d24 1 QC6.53 [4.83, 8.25]2.21-6.53 [-8.25, -4.83]7.01 [5.16, 8.57]0% [0%, 0%]0%12%-1.03+0.312026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC6.53 [4.62, 8.40]2.21-6.53 [-8.40, -4.62]7.01 [4.90, 8.67]0% [0%, 0%]0%12%-1.03+0.312026-08-07 → 2026-08-30
tmax00Znearest365d30 1 QC6.89 [5.28, 8.63]2.25-6.89 [-8.63, -5.28]7.38 [5.67, 8.86]0% [0%, 0%]0%10%-0.60+0.492026-01-07 → 2026-08-30
tmax00Znearestall30 1 QC6.89 [5.26, 8.51]2.25-6.89 [-8.51, -5.26]7.38 [5.66, 8.78]0% [0%, 0%]0%10%-0.60+0.492026-01-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC6.54 [4.94, 8.19]2.15-6.54 [-8.19, -4.94]7.02 [5.39, 8.44]4% [0%, 12%]4%8%-1.04+0.332026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC6.54 [4.78, 8.29]2.15-6.54 [-8.29, -4.78]7.02 [5.15, 8.53]4% [0%, 14%]4%8%-1.04+0.332026-08-07 → 2026-08-30
tmax12Zbilinear365d29 1 QC6.64 [5.02, 8.24]2.15-6.64 [-8.24, -5.02]7.11 [5.49, 8.45]3% [0%, 12%]3%7%-0.78+0.432026-01-07 → 2026-08-30
tmax12Zbilinearall29 1 QC6.64 [5.08, 8.22]2.15-6.64 [-8.22, -5.08]7.11 [5.44, 8.48]3% [0%, 11%]3%7%-0.78+0.432026-01-07 → 2026-08-30
tmax12Znearest30d24 1 QC6.75 [5.17, 8.35]2.12-6.75 [-8.35, -5.17]7.20 [5.62, 8.58]4% [0%, 12%]4%8%-1.10+0.332026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC6.75 [5.03, 8.45]2.12-6.75 [-8.45, -5.03]7.20 [5.37, 8.68]4% [0%, 14%]4%8%-1.10+0.332026-08-07 → 2026-08-30
tmax12Znearest365d29 1 QC6.83 [5.27, 8.37]2.13-6.83 [-8.37, -5.27]7.27 [5.70, 8.60]3% [0%, 12%]3%7%-0.83+0.432026-01-07 → 2026-08-30
tmax12Znearestall29 1 QC6.83 [5.31, 8.38]2.13-6.83 [-8.38, -5.31]7.27 [5.66, 8.62]3% [0%, 11%]3%7%-0.83+0.432026-01-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC2.50 [2.09, 2.83]2.38+0.90 [-0.90, 2.50]2.93 [2.45, 3.31]17% [4%, 33%]38%67%+0.08+0.122026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC2.50 [2.05, 2.83]2.38+0.90 [-0.98, 2.70]2.93 [2.40, 3.32]17% [0%, 33%]38%67%+0.08+0.122026-08-07 → 2026-08-30
tmin00Zbilinear365d30 1 QC2.82 [2.32, 3.54]2.69+0.73 [-1.23, 2.63]3.42 [2.71, 4.33]13% [0%, 28%]37%63%+0.39+0.422026-01-07 → 2026-08-30
tmin00Zbilinearall30 1 QC2.82 [2.29, 3.61]2.69+0.73 [-1.28, 2.51]3.42 [2.70, 4.40]13% [0%, 29%]37%63%+0.39+0.422026-01-07 → 2026-08-30
tmin00Znearest30d24 1 QC2.48 [2.06, 2.81]2.37+0.86 [-0.93, 2.44]2.91 [2.43, 3.27]21% [8%, 36%]38%67%+0.08+0.132026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC2.48 [2.00, 2.82]2.37+0.86 [-1.01, 2.66]2.91 [2.39, 3.28]21% [6%, 38%]38%67%+0.08+0.132026-08-07 → 2026-08-30
tmin00Znearest365d30 1 QC2.81 [2.29, 3.55]2.68+0.72 [-1.18, 2.59]3.39 [2.72, 4.28]17% [3%, 30%]37%63%+0.40+0.432026-01-07 → 2026-08-30
tmin00Znearestall30 1 QC2.81 [2.26, 3.61]2.68+0.72 [-1.28, 2.49]3.39 [2.69, 4.30]17% [0%, 32%]37%63%+0.40+0.432026-01-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC2.33 [1.82, 2.65]2.26+0.50 [-1.19, 2.12]2.70 [2.24, 3.05]21% [7%, 44%]50%67%+0.14+0.172026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC2.33 [1.74, 2.64]2.26+0.50 [-1.26, 2.39]2.70 [2.15, 3.07]21% [5%, 50%]50%67%+0.14+0.172026-08-07 → 2026-08-30
tmin12Zbilinear365d29 1 QC2.44 [2.02, 2.80]2.38+0.31 [-1.41, 2.15]2.83 [2.39, 3.20]21% [5%, 39%]48%62%+0.39+0.412026-01-07 → 2026-08-30
tmin12Zbilinearall29 1 QC2.44 [1.99, 2.81]2.38+0.31 [-1.44, 2.00]2.83 [2.39, 3.22]21% [5%, 42%]48%62%+0.39+0.412026-01-07 → 2026-08-30
tmin12Znearest30d24 1 QC2.31 [1.78, 2.63]2.24+0.48 [-1.22, 2.09]2.68 [2.22, 3.03]21% [7%, 44%]50%67%+0.15+0.182026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC2.31 [1.70, 2.61]2.24+0.48 [-1.28, 2.34]2.68 [2.10, 3.05]21% [5%, 50%]50%67%+0.15+0.182026-08-07 → 2026-08-30
tmin12Znearest365d29 1 QC2.42 [2.01, 2.79]2.37+0.31 [-1.40, 2.13]2.81 [2.37, 3.17]21% [5%, 39%]45%62%+0.40+0.422026-01-07 → 2026-08-30
tmin12Znearestall29 1 QC2.42 [1.97, 2.81]2.37+0.31 [-1.43, 1.99]2.81 [2.38, 3.21]21% [5%, 42%]45%62%+0.40+0.422026-01-07 → 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 KIAH, lead day 6, 00Z bilinear tmax+20+100-10-202026-08-07: -5.27 °F2026-08-08: -7.68 °F2026-08-09: -3.71 °F2026-08-10: -1.64 °F2026-08-11: -4.08 °F2026-08-12: -5.64 °F2026-08-13: -4.81 °F2026-08-14: -2 °F2026-08-15: -7 °F2026-08-16: -7.82 °F2026-08-17: -8.19 °F2026-08-18: -7.74 °F2026-08-19: -6.06 °F2026-08-20: -11.05 °F2026-08-21: -9.01 °F2026-08-22: -11.05 °F2026-08-23: -8.72 °F2026-08-24: -8.97 °F2026-08-25: -8.6 °F2026-08-26: -6.92 °F2026-08-27: -3.96 °F2026-08-28: -2.8 °F2026-08-29: -3.88 °F2026-08-30: -4.36 °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
2026-08-30-4.36
2026-08-29-3.88
2026-08-28-2.80
2026-08-27-3.96
2026-08-26-6.92
2026-08-25-8.60
2026-08-24-8.97
2026-08-23-8.72
2026-08-22-11.05
2026-08-21-9.01
2026-08-20-11.05
2026-08-19-6.06
2026-08-18-7.74
2026-08-17-8.19
2026-08-16-7.82
2026-08-15-7.00
2026-08-14-2.00
2026-08-13-4.81
2026-08-12-5.64
2026-08-11-4.08
2026-08-10-1.64
2026-08-09-3.71
2026-08-08-7.68
2026-08-07-5.27

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KIAH, lead day 6-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 4 days-10 to -8 °F: 7 days-8 to -6 °F: 7 days-6 to -4 °F: 6 days-4 to -2 °F: 4 days-2 to 0 °F: 2 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| 6.96 · P90 |e| 10.82 °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
-18.00-16.000
-16.00-14.000
-14.00-12.000
-12.00-10.004
-10.00-8.007
-8.00-6.007
-6.00-4.006
-4.00-2.004
-2.00+0.002
+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
2026-08246.29 -6.29
2026-0168.41 -8.41

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 +3.04 [1.65, 4.21] yes
NCEP GFS 24 +3.65 [0.94, 6.20] yes
ECMWF IFS HRES 19 +2.96 [0.10, 4.96] yes
Persistence (baseline) 24 +3.08 [0.43, 5.40] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KIAH (Houston Bush), 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/KIAH/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