Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

Houston Bush · NCEP GFS · lead day 4

KIAH · gfs · 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, gfs-0p25, starting 2026-08-01 — 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
tmax00Zbilinear30d26 1 QC2.15 [1.29, 3.16]2.07-0.83 [-2.48, 0.74]3.09 [1.74, 4.17]42% [14%, 68%]58%73%+0.24+0.262026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC2.15 [1.19, 3.33]2.07-0.83 [-2.83, 0.91]3.09 [1.65, 4.27]42% [5%, 71%]58%73%+0.24+0.262026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC2.15 [1.07, 3.58]2.07-0.83 [-2.92, 0.95]3.09 [1.38, 4.34]42% [0%, 71%]58%73%+0.24+0.262026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC2.15 [1.02, 3.42]2.07-0.83 [-3.01, 0.95]3.09 [1.32, 4.28]42% [3%, 72%]58%73%+0.24+0.262026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC2.19 [1.29, 3.27]2.14-0.85 [-2.51, 0.72]3.23 [1.80, 4.38]46% [21%, 68%]58%73%+0.22+0.242026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC2.19 [1.18, 3.44]2.14-0.85 [-2.86, 0.85]3.23 [1.68, 4.48]46% [14%, 71%]58%73%+0.22+0.242026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC2.19 [1.07, 3.66]2.14-0.85 [-2.95, 0.90]3.23 [1.39, 4.55]46% [7%, 71%]58%73%+0.22+0.242026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC2.19 [1.03, 3.52]2.14-0.85 [-3.04, 0.89]3.23 [1.36, 4.47]46% [12%, 72%]58%73%+0.22+0.242026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC1.74 [1.18, 2.21]1.70-0.20 [-1.51, 1.17]2.38 [1.59, 2.96]35% [14%, 58%]69%88%+0.38+0.392026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC1.74 [1.12, 2.17]1.70-0.20 [-1.62, 1.37]2.38 [1.53, 2.98]35% [10%, 63%]69%88%+0.38+0.392026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC1.74 [1.07, 2.22]1.70-0.20 [-1.69, 1.47]2.38 [1.45, 2.97]35% [7%, 62%]69%88%+0.38+0.392026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC1.74 [0.91, 2.20]1.70-0.20 [-1.71, 1.43]2.38 [1.33, 2.98]35% [7%, 67%]69%88%+0.38+0.392026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC1.77 [1.20, 2.25]1.75-0.19 [-1.47, 1.14]2.41 [1.58, 3.05]38% [15%, 65%]65%88%+0.37+0.382026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC1.77 [1.13, 2.20]1.75-0.19 [-1.56, 1.32]2.41 [1.50, 3.04]38% [10%, 71%]65%88%+0.37+0.382026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC1.77 [1.09, 2.23]1.75-0.19 [-1.64, 1.45]2.41 [1.41, 3.05]38% [7%, 71%]65%88%+0.37+0.382026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC1.77 [0.95, 2.22]1.75-0.19 [-1.69, 1.41]2.41 [1.29, 3.06]38% [8%, 71%]65%88%+0.37+0.382026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC3.34 [2.26, 4.39]2.20+3.24 [2.10, 4.34]4.10 [3.03, 4.98]23% [7%, 39%]38%46%-0.17+0.232026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC3.34 [2.20, 4.50]2.20+3.24 [2.06, 4.47]4.10 [2.87, 5.09]23% [0%, 40%]38%46%-0.17+0.232026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC3.34 [2.07, 4.58]2.20+3.24 [1.87, 4.53]4.10 [2.70, 5.14]23% [0%, 43%]38%46%-0.17+0.232026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC3.34 [1.94, 4.45]2.20+3.24 [1.84, 4.42]4.10 [2.70, 5.06]23% [0%, 43%]38%46%-0.17+0.232026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC3.28 [2.36, 4.12]2.02+3.20 [2.22, 4.08]4.01 [3.06, 4.74]23% [7%, 39%]38%42%-0.15+0.292026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC3.28 [2.31, 4.21]2.02+3.20 [2.20, 4.20]4.01 [2.95, 4.79]23% [0%, 40%]38%42%-0.15+0.292026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC3.28 [2.20, 4.26]2.02+3.20 [2.08, 4.25]4.01 [2.86, 4.79]23% [0%, 43%]38%42%-0.15+0.292026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC3.28 [2.09, 4.20]2.02+3.20 [1.96, 4.19]4.01 [2.74, 4.75]23% [0%, 43%]38%42%-0.15+0.292026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC3.42 [2.23, 4.50]2.17+3.27 [1.99, 4.46]4.13 [2.94, 4.98]23% [5%, 44%]38%42%-0.20+0.242026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC3.42 [2.19, 4.67]2.17+3.27 [1.93, 4.67]4.13 [2.81, 5.05]23% [0%, 45%]38%42%-0.20+0.242026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC3.42 [2.01, 4.67]2.17+3.27 [1.78, 4.67]4.13 [2.63, 5.13]23% [0%, 47%]38%42%-0.20+0.242026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC3.42 [1.93, 4.63]2.17+3.27 [1.71, 4.61]4.13 [2.58, 5.02]23% [0%, 50%]38%42%-0.20+0.242026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC3.38 [2.34, 4.32]2.01+3.28 [2.18, 4.28]4.09 [3.02, 4.86]19% [5%, 36%]31%42%-0.19+0.292026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC3.38 [2.29, 4.48]2.01+3.28 [2.13, 4.46]4.09 [2.94, 4.91]19% [0%, 36%]31%42%-0.19+0.292026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC3.38 [2.17, 4.44]2.01+3.28 [2.01, 4.40]4.09 [2.76, 4.92]19% [0%, 38%]31%42%-0.19+0.292026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC3.38 [2.04, 4.44]2.01+3.28 [1.87, 4.44]4.09 [2.64, 4.87]19% [0%, 37%]31%42%-0.19+0.292026-08-05 → 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 NCEP GFS at KIAH, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -0.35 °F2026-08-06: +0.35 °F2026-08-07: -2.03 °F2026-08-08: +0.87 °F2026-08-09: -1.08 °F2026-08-10: +7.71 °F2026-08-11: +0.64 °F2026-08-12: +0.49 °F2026-08-13: +0.68 °F2026-08-14: +2.77 °F2026-08-15: +0.09 °F2026-08-16: -0.72 °F2026-08-17: +0.76 °F2026-08-18: -1.91 °F2026-08-19: +0.5 °F2026-08-20: -0.82 °F2026-08-21: -3.23 °F2026-08-22: -3.11 °F2026-08-23: -1.04 °F2026-08-24: -3.79 °F2026-08-25: -3.41 °F2026-08-26: -2.67 °F2026-08-27: -9.59 °F2026-08-28: -1.06 °F2026-08-29: +2.17 °F2026-08-30: -3.94 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.94
2026-08-29+2.17
2026-08-28-1.06
2026-08-27-9.59
2026-08-26-2.67
2026-08-25-3.41
2026-08-24-3.79
2026-08-23-1.04
2026-08-22-3.11
2026-08-21-3.23
2026-08-20-0.82
2026-08-19+0.50
2026-08-18-1.91
2026-08-17+0.76
2026-08-16-0.72
2026-08-15+0.09
2026-08-14+2.77
2026-08-13+0.68
2026-08-12+0.49
2026-08-11+0.64
2026-08-10+7.71
2026-08-09-1.08
2026-08-08+0.87
2026-08-07-2.03
2026-08-06+0.35
2026-08-05-0.35

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KIAH, lead day 4-10 to -9 °F: 1 day-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 0 days-5 to -4 °F: 0 days-4 to -3 °F: 5 days-3 to -2 °F: 2 days-2 to -1 °F: 4 days-1 to 0 °F: 3 days0 to 1 °F: 8 days1 to 2 °F: 0 days2 to 3 °F: 2 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 1 day8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 1.07 · P90 |e| 3.86 °F-100+10 °Fn = 26 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
-10.00-9.001
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.000
-5.00-4.000
-4.00-3.005
-3.00-2.002
-2.00-1.004
-1.00+0.003
+0.00+1.008
+1.00+2.000
+2.00+3.002
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.001
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08262.15 -0.83

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 26 -1.45 [-2.51, -0.31] yes
GraphCast (IFS init) 25 -4.34 [-5.92, -2.58] yes
ECMWF IFS HRES 20 -1.69 [-2.93, -0.68] yes
Persistence (baseline) 26 -0.66 [-1.82, 0.81] no

Cite this page

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

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