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 5

KIAH · gfs · lead 5

Target day = initialization date + 5 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
tmax00Zbilinear30d25 1 QC2.29 [1.16, 3.95]2.36-1.17 [-3.62, 0.97]3.74 [1.51, 5.91]40% [22%, 60%]68%72%+0.22+0.202026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC2.29 [1.09, 4.24]2.36-1.17 [-4.12, 1.33]3.74 [1.41, 6.33]40% [21%, 60%]68%72%+0.22+0.202026-08-06 → 2026-08-30
tmax00Zbilinear365d25 1 QC2.29 [1.06, 4.56]2.36-1.17 [-4.42, 1.33]3.74 [1.33, 6.45]40% [19%, 62%]68%72%+0.22+0.202026-08-06 → 2026-08-30
tmax00Zbilinearall25 1 QC2.29 [1.00, 4.14]2.36-1.17 [-4.06, 1.38]3.74 [1.33, 6.11]40% [19%, 64%]68%72%+0.22+0.202026-08-06 → 2026-08-30
tmax00Znearest30d25 1 QC2.15 [1.00, 3.76]2.23-1.13 [-3.42, 0.87]3.57 [1.41, 5.65]44% [24%, 65%]68%72%+0.27+0.252026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC2.15 [0.93, 4.02]2.23-1.13 [-3.82, 1.11]3.57 [1.33, 6.01]44% [22%, 68%]68%72%+0.27+0.252026-08-06 → 2026-08-30
tmax00Znearest365d25 1 QC2.15 [0.86, 4.33]2.23-1.13 [-4.18, 1.15]3.57 [1.17, 6.14]44% [20%, 68%]68%72%+0.27+0.252026-08-06 → 2026-08-30
tmax00Znearestall25 1 QC2.15 [0.83, 3.93]2.23-1.13 [-3.82, 1.16]3.57 [1.17, 5.81]44% [19%, 71%]68%72%+0.27+0.252026-08-06 → 2026-08-30
tmax12Zbilinear30d25 1 QC2.23 [1.17, 3.21]2.25-0.77 [-2.12, 0.46]3.32 [1.43, 4.43]36% [14%, 60%]64%80%+0.25+0.242026-08-06 → 2026-08-30
tmax12Zbilinear90d25 1 QC2.23 [0.95, 3.31]2.25-0.77 [-2.31, 0.53]3.32 [1.19, 4.54]36% [12%, 61%]64%80%+0.25+0.242026-08-06 → 2026-08-30
tmax12Zbilinear365d25 1 QC2.23 [0.89, 3.32]2.25-0.77 [-2.41, 0.72]3.32 [1.10, 4.52]36% [10%, 63%]64%80%+0.25+0.242026-08-06 → 2026-08-30
tmax12Zbilinearall25 1 QC2.23 [0.89, 3.31]2.25-0.77 [-2.43, 0.64]3.32 [1.09, 4.54]36% [10%, 67%]64%80%+0.25+0.242026-08-06 → 2026-08-30
tmax12Znearest30d25 1 QC2.40 [1.16, 3.52]2.44-0.94 [-2.28, 0.30]3.65 [1.49, 4.94]36% [9%, 64%]60%76%+0.19+0.172026-08-06 → 2026-08-30
tmax12Znearest90d25 1 QC2.40 [1.05, 3.58]2.44-0.94 [-2.42, 0.38]3.65 [1.28, 4.96]36% [0%, 67%]60%76%+0.19+0.172026-08-06 → 2026-08-30
tmax12Znearest365d25 1 QC2.40 [0.91, 3.60]2.44-0.94 [-2.56, 0.47]3.65 [1.10, 5.07]36% [0%, 71%]60%76%+0.19+0.172026-08-06 → 2026-08-30
tmax12Znearestall25 1 QC2.40 [0.92, 3.57]2.44-0.94 [-2.53, 0.45]3.65 [1.14, 4.96]36% [0%, 71%]60%76%+0.19+0.172026-08-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC3.55 [2.25, 4.73]2.19+3.35 [1.93, 4.71]4.20 [2.97, 5.04]24% [5%, 45%]32%40%-0.27+0.222026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC3.55 [2.20, 4.89]2.19+3.35 [1.84, 4.87]4.20 [2.91, 5.15]24% [0%, 45%]32%40%-0.27+0.222026-08-06 → 2026-08-30
tmin00Zbilinear365d25 1 QC3.55 [1.97, 4.89]2.19+3.35 [1.62, 4.87]4.20 [2.79, 5.18]24% [0%, 50%]32%40%-0.27+0.222026-08-06 → 2026-08-30
tmin00Zbilinearall25 1 QC3.55 [1.83, 4.92]2.19+3.35 [1.49, 4.91]4.20 [2.59, 5.12]24% [0%, 50%]32%40%-0.27+0.222026-08-06 → 2026-08-30
tmin00Znearest30d25 1 QC3.54 [2.34, 4.63]2.09+3.36 [2.05, 4.58]4.17 [3.07, 4.91]24% [5%, 45%]28%36%-0.26+0.252026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC3.54 [2.30, 4.71]2.09+3.36 [1.98, 4.70]4.17 [3.01, 4.99]24% [0%, 45%]28%36%-0.26+0.252026-08-06 → 2026-08-30
tmin00Znearest365d25 1 QC3.54 [2.11, 4.74]2.09+3.36 [1.79, 4.73]4.17 [2.94, 5.03]24% [0%, 50%]28%36%-0.26+0.252026-08-06 → 2026-08-30
tmin00Znearestall25 1 QC3.54 [1.94, 4.74]2.09+3.36 [1.64, 4.74]4.17 [2.78, 4.98]24% [0%, 50%]28%36%-0.26+0.252026-08-06 → 2026-08-30
tmin12Zbilinear30d25 1 QC3.66 [2.33, 4.85]2.26+3.47 [2.05, 4.83]4.45 [3.12, 5.47]20% [5%, 39%]28%40%-0.31+0.192026-08-06 → 2026-08-30
tmin12Zbilinear90d25 1 QC3.66 [2.29, 5.04]2.26+3.47 [1.97, 4.99]4.45 [3.05, 5.58]20% [0%, 38%]28%40%-0.31+0.192026-08-06 → 2026-08-30
tmin12Zbilinear365d25 1 QC3.66 [2.11, 5.10]2.26+3.47 [1.75, 5.09]4.45 [2.86, 5.66]20% [0%, 42%]28%40%-0.31+0.192026-08-06 → 2026-08-30
tmin12Zbilinearall25 1 QC3.66 [2.02, 5.02]2.26+3.47 [1.69, 4.99]4.45 [2.60, 5.62]20% [0%, 43%]28%40%-0.31+0.192026-08-06 → 2026-08-30
tmin12Znearest30d25 1 QC3.69 [2.55, 4.70]2.22+3.47 [2.24, 4.63]4.46 [3.23, 5.36]20% [5%, 39%]28%40%-0.32+0.212026-08-06 → 2026-08-30
tmin12Znearest90d25 1 QC3.69 [2.51, 4.83]2.22+3.47 [2.21, 4.80]4.46 [3.24, 5.47]20% [0%, 38%]28%40%-0.32+0.212026-08-06 → 2026-08-30
tmin12Znearest365d25 1 QC3.69 [2.46, 4.89]2.22+3.47 [2.07, 4.81]4.46 [3.08, 5.47]20% [0%, 42%]28%40%-0.32+0.212026-08-06 → 2026-08-30
tmin12Znearestall25 1 QC3.69 [2.27, 4.82]2.22+3.47 [1.96, 4.81]4.46 [2.74, 5.50]20% [0%, 43%]28%40%-0.32+0.212026-08-06 → 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 5, 00Z bilinear tmax+20+100-10-202026-08-06: +0.94 °F2026-08-07: +1.24 °F2026-08-08: +1.54 °F2026-08-09: +0.93 °F2026-08-10: +3.59 °F2026-08-11: +1.77 °F2026-08-12: +0.49 °F2026-08-13: +0.19 °F2026-08-14: +3.34 °F2026-08-15: -0.62 °F2026-08-16: -0.75 °F2026-08-17: -0.3 °F2026-08-18: -1.22 °F2026-08-19: -0.01 °F2026-08-20: -1.42 °F2026-08-21: -2.43 °F2026-08-22: -3.73 °F2026-08-23: -0.05 °F2026-08-24: -2 °F2026-08-25: -3.26 °F2026-08-26: -4.3 °F2026-08-27: -7.46 °F2026-08-28: -14.2 °F2026-08-29: -1.23 °F2026-08-30: -0.35 °F2026-08-062026-08-30°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 (25 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-0.35
2026-08-29-1.23
2026-08-28-14.20
2026-08-27-7.46
2026-08-26-4.30
2026-08-25-3.26
2026-08-24-2.00
2026-08-23-0.05
2026-08-22-3.73
2026-08-21-2.43
2026-08-20-1.42
2026-08-19-0.01
2026-08-18-1.22
2026-08-17-0.30
2026-08-16-0.75
2026-08-15-0.62
2026-08-14+3.34
2026-08-13+0.19
2026-08-12+0.49
2026-08-11+1.77
2026-08-10+3.59
2026-08-09+0.93
2026-08-08+1.54
2026-08-07+1.24
2026-08-06+0.94

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KIAH, lead day 5-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 1 day-14 to -12 °F: 0 days-12 to -10 °F: 0 days-10 to -8 °F: 0 days-8 to -6 °F: 1 day-6 to -4 °F: 1 day-4 to -2 °F: 3 days-2 to 0 °F: 10 days0 to 2 °F: 7 days2 to 4 °F: 2 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| 1.24 · P90 |e| 4.07 °F-200+20 °Fn = 25 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
-16.00-14.001
-14.00-12.000
-12.00-10.000
-10.00-8.000
-8.00-6.001
-6.00-4.001
-4.00-2.003
-2.00+0.0010
+0.00+2.007
+2.00+4.002
+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
2026-08252.29 -1.17

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25

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 25 -0.98 [-2.62, 1.54] no
GraphCast (IFS init) 25 -3.93 [-6.19, -1.18] yes
ECMWF IFS HRES 18 -1.37 [-3.15, 0.53] no
Persistence (baseline) 25 -0.67 [-2.33, 1.61] no

Cite this page

ShortCastCheck, KIAH gfs lead 5, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KIAH/model/gfs/lead/5/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KIAH (Houston Bush), model gfs, lead day 5. 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/5/

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