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

Houston Bush · GraphCast (IFS init) · lead day 8

KIAH · graphcast_ifs · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 1 QC5.97 [3.72, 7.80]2.19-5.97 [-7.80, -3.72]6.51 [4.16, 7.99]0% [0%, 0%]9%18%-0.71+0.352026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC5.97 [2.99, 7.88]2.19-5.97 [-7.88, -2.99]6.51 [3.29, 8.05]0% [0%, 0%]9%18%-0.71+0.352026-08-09 → 2026-08-30
tmax00Zbilinear365d28 1 QC5.57 [3.58, 7.44]2.68-5.01 [-7.32, -2.03]6.14 [4.04, 7.71]4% [0%, 13%]11%21%+0.00+0.532026-01-09 → 2026-08-30
tmax00Zbilinearall28 1 QC5.57 [3.61, 7.34]2.68-5.01 [-7.17, -1.86]6.14 [4.04, 7.64]4% [0%, 14%]11%21%+0.00+0.532026-01-09 → 2026-08-30
tmax00Znearest30d22 1 QC6.21 [4.06, 7.98]2.13-6.21 [-7.98, -4.06]6.70 [4.43, 8.17]0% [0%, 0%]9%14%-0.77+0.372026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC6.21 [3.34, 8.07]2.13-6.21 [-8.07, -3.34]6.70 [3.61, 8.22]0% [0%, 0%]9%14%-0.77+0.372026-08-09 → 2026-08-30
tmax00Znearest365d28 1 QC5.77 [3.76, 7.63]2.68-5.19 [-7.50, -2.23]6.31 [4.18, 7.88]4% [0%, 13%]11%18%-0.03+0.532026-01-09 → 2026-08-30
tmax00Znearestall28 1 QC5.77 [3.80, 7.49]2.68-5.19 [-7.37, -1.89]6.31 [4.22, 7.79]4% [0%, 14%]11%18%-0.03+0.532026-01-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC6.63 [4.36, 8.54]2.37-6.63 [-8.54, -4.36]7.16 [4.81, 8.74]0% [0%, 0%]9%14%-0.89+0.292026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC6.63 [3.68, 8.67]2.37-6.63 [-8.67, -3.68]7.16 [4.15, 8.84]0% [0%, 0%]9%14%-0.89+0.292026-08-09 → 2026-08-30
tmax12Zbilinear365d27 1 QC6.92 [4.67, 8.80]2.93-6.32 [-8.26, -3.86]7.43 [5.30, 8.93]0% [0%, 0%]7%11%-0.32+0.462026-01-09 → 2026-08-30
tmax12Zbilinearall27 1 QC6.92 [4.79, 8.83]2.93-6.32 [-8.30, -4.02]7.43 [5.27, 8.95]0% [0%, 0%]7%11%-0.32+0.462026-01-09 → 2026-08-30
tmax12Znearest30d22 1 QC6.85 [4.63, 8.74]2.34-6.85 [-8.74, -4.63]7.36 [5.03, 8.94]0% [0%, 0%]5%14%-0.96+0.302026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC6.85 [3.94, 8.84]2.34-6.85 [-8.84, -3.94]7.36 [4.36, 9.02]0% [0%, 0%]5%14%-0.96+0.302026-08-09 → 2026-08-30
tmax12Znearest365d27 1 QC7.11 [4.93, 8.96]2.90-6.51 [-8.44, -4.10]7.59 [5.48, 9.08]0% [0%, 0%]4%11%-0.35+0.462026-01-09 → 2026-08-30
tmax12Znearestall27 1 QC7.11 [5.03, 8.98]2.90-6.51 [-8.46, -4.20]7.59 [5.48, 9.11]0% [0%, 0%]4%11%-0.35+0.462026-01-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC2.91 [2.43, 3.37]2.88+0.96 [-1.08, 3.13]3.30 [2.71, 3.77]14% [4%, 26%]27%50%+0.15+0.152026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC2.91 [2.44, 3.43]2.88+0.96 [-1.20, 3.30]3.30 [2.72, 3.86]14% [0%, 27%]27%50%+0.15+0.152026-08-09 → 2026-08-30
tmin00Zbilinear365d28 1 QC2.84 [2.25, 3.35]2.88+0.90 [-1.05, 2.95]3.33 [2.67, 3.85]18% [6%, 31%]32%54%+0.50+0.492026-01-09 → 2026-08-30
tmin00Zbilinearall28 1 QC2.84 [2.26, 3.28]2.88+0.90 [-1.10, 2.78]3.33 [2.63, 3.81]18% [5%, 35%]32%54%+0.50+0.492026-01-09 → 2026-08-30
tmin00Znearest30d22 1 QC2.89 [2.43, 3.34]2.85+0.94 [-1.10, 3.10]3.27 [2.70, 3.74]14% [4%, 26%]27%50%+0.15+0.162026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC2.89 [2.43, 3.40]2.85+0.94 [-1.22, 3.28]3.27 [2.67, 3.82]14% [0%, 27%]27%50%+0.15+0.162026-08-09 → 2026-08-30
tmin00Znearest365d28 1 QC2.83 [2.24, 3.33]2.86+0.89 [-1.04, 2.92]3.33 [2.66, 3.86]21% [7%, 45%]32%54%+0.50+0.502026-01-09 → 2026-08-30
tmin00Znearestall28 1 QC2.83 [2.25, 3.26]2.86+0.89 [-1.09, 2.77]3.33 [2.62, 3.83]21% [6%, 46%]32%54%+0.50+0.502026-01-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC2.64 [2.17, 3.10]2.62+0.70 [-1.28, 2.80]2.98 [2.40, 3.48]9% [0%, 20%]27%64%+0.23+0.232026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC2.64 [2.20, 3.14]2.62+0.70 [-1.42, 2.96]2.98 [2.40, 3.55]9% [0%, 20%]27%64%+0.23+0.232026-08-09 → 2026-08-30
tmin12Zbilinear365d27 1 QC2.88 [2.30, 3.56]2.81+0.62 [-1.33, 2.55]3.44 [2.55, 4.43]11% [0%, 23%]30%59%+0.45+0.472026-01-09 → 2026-08-30
tmin12Zbilinearall27 1 QC2.88 [2.29, 3.69]2.81+0.62 [-1.35, 2.54]3.44 [2.55, 4.63]11% [0%, 24%]30%59%+0.45+0.472026-01-09 → 2026-08-30
tmin12Znearest30d22 1 QC2.62 [2.15, 3.08]2.60+0.67 [-1.31, 2.76]2.96 [2.37, 3.46]14% [0%, 25%]23%64%+0.23+0.232026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC2.62 [2.18, 3.12]2.60+0.67 [-1.45, 2.92]2.96 [2.38, 3.53]14% [0%, 26%]23%64%+0.23+0.232026-08-09 → 2026-08-30
tmin12Znearest365d27 1 QC2.86 [2.28, 3.54]2.80+0.59 [-1.35, 2.54]3.43 [2.52, 4.45]15% [0%, 29%]26%59%+0.46+0.472026-01-09 → 2026-08-30
tmin12Znearestall27 1 QC2.86 [2.27, 3.69]2.80+0.59 [-1.36, 2.51]3.43 [2.53, 4.64]15% [0%, 27%]26%59%+0.46+0.472026-01-09 → 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 8, 00Z bilinear tmax+20+100-10-202026-08-09: -2.66 °F2026-08-10: -1.2 °F2026-08-11: -2.11 °F2026-08-12: -4.46 °F2026-08-13: -4.53 °F2026-08-14: -1.36 °F2026-08-15: -6.72 °F2026-08-16: -6.31 °F2026-08-17: -7.72 °F2026-08-18: -8.31 °F2026-08-19: -7.33 °F2026-08-20: -7.03 °F2026-08-21: -8.07 °F2026-08-22: -10.64 °F2026-08-23: -8.1 °F2026-08-24: -9.82 °F2026-08-25: -8.08 °F2026-08-26: -7.54 °F2026-08-27: -6.05 °F2026-08-28: -4.53 °F2026-08-29: -4.01 °F2026-08-30: -4.81 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-4.81
2026-08-29-4.01
2026-08-28-4.53
2026-08-27-6.05
2026-08-26-7.54
2026-08-25-8.08
2026-08-24-9.82
2026-08-23-8.10
2026-08-22-10.64
2026-08-21-8.07
2026-08-20-7.03
2026-08-19-7.33
2026-08-18-8.31
2026-08-17-7.72
2026-08-16-6.31
2026-08-15-6.72
2026-08-14-1.36
2026-08-13-4.53
2026-08-12-4.46
2026-08-11-2.11
2026-08-10-1.20
2026-08-09-2.66

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KIAH, lead day 8-20 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: 1 day-10 to -8 °F: 5 days-8 to -6 °F: 7 days-6 to -4 °F: 7 days-4 to -2 °F: 4 days-2 to 0 °F: 2 days0 to 2 °F: 1 day2 to 4 °F: 0 days4 to 6 °F: 0 days6 to 8 °F: 1 day8 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| 5.99 · P90 |e| 8.16 °F-200+20 °Fn = 28 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
-12.00-10.001
-10.00-8.005
-8.00-6.007
-6.00-4.007
-4.00-2.004
-2.00+0.002
+0.00+2.001
+2.00+4.000
+4.00+6.000
+6.00+8.001
+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
2026-08225.97 -5.97
2026-0164.09 -1.46

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 27
GraphCast (IFS init)2026-01-09 → 2026-08-30 27

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 22 +2.53 [0.89, 3.48] yes
NCEP GFS 22 +3.53 [0.70, 5.03] yes
ECMWF IFS HRES 17 +2.78 [1.01, 3.88] yes
Persistence (baseline) 22 +2.47 [-0.59, 4.42] no

Cite this page

ShortCastCheck, KIAH graphcast_ifs lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KIAH/model/graphcast_ifs/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KIAH (Houston Bush), model graphcast_ifs, lead day 8. 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/8/

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