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

San Antonio Intl · GraphCast (IFS init) · lead day 1

KSAT · graphcast_ifs · lead 1

Target day = initialization date + 1 day. 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
tmax00Zbilinear30d27 1 QC5.72 [5.04, 6.21]0.97-5.72 [-6.21, -5.04]5.83 [5.15, 6.30]0% [0%, 0%]0%0%-4.72+0.042026-08-02 → 2026-08-30
tmax00Zbilinear90d27 1 QC5.72 [4.88, 6.25]0.97-5.72 [-6.25, -4.88]5.83 [4.97, 6.33]0% [0%, 0%]0%0%-4.72+0.042026-08-02 → 2026-08-30
tmax00Zbilinear365d33 1 QC6.18 [5.35, 7.29]1.34-6.18 [-7.29, -5.35]6.41 [5.49, 7.56]0% [0%, 0%]0%0%-1.76+0.412026-01-02 → 2026-08-30
tmax00Zbilinearall33 1 QC6.18 [5.23, 7.18]1.34-6.18 [-7.18, -5.23]6.41 [5.40, 7.46]0% [0%, 0%]0%0%-1.76+0.412026-01-02 → 2026-08-30
tmax00Znearest30d27 1 QC5.30 [4.63, 5.78]0.95-5.30 [-5.78, -4.63]5.42 [4.75, 5.86]0% [0%, 0%]0%0%-4.30+0.072026-08-02 → 2026-08-30
tmax00Znearest90d27 1 QC5.30 [4.47, 5.83]0.95-5.30 [-5.83, -4.47]5.42 [4.56, 5.91]0% [0%, 0%]0%0%-4.30+0.072026-08-02 → 2026-08-30
tmax00Znearest365d33 1 QC5.82 [4.94, 7.03]1.39-5.82 [-7.03, -4.94]6.08 [5.07, 7.37]0% [0%, 0%]0%0%-1.59+0.392026-01-02 → 2026-08-30
tmax00Znearestall33 1 QC5.82 [4.83, 6.88]1.39-5.82 [-6.88, -4.83]6.08 [4.99, 7.23]0% [0%, 0%]0%0%-1.59+0.392026-01-02 → 2026-08-30
tmax12Zbilinear30d27 1 QC6.63 [6.10, 7.08]1.01-6.63 [-7.08, -6.10]6.74 [6.18, 7.16]0% [0%, 0%]0%0%-5.63+0.002026-08-02 → 2026-08-30
tmax12Zbilinear90d27 1 QC6.63 [6.00, 7.17]1.01-6.63 [-7.17, -6.00]6.74 [6.08, 7.26]0% [0%, 0%]0%0%-5.63+0.002026-08-02 → 2026-08-30
tmax12Zbilinear365d32 1 QC6.88 [6.26, 7.69]1.24-6.88 [-7.69, -6.26]7.04 [6.37, 7.87]0% [0%, 0%]0%0%-2.06+0.462026-01-02 → 2026-08-30
tmax12Zbilinearall32 1 QC6.88 [6.22, 7.60]1.24-6.88 [-7.60, -6.22]7.04 [6.32, 7.77]0% [0%, 0%]0%0%-2.06+0.462026-01-02 → 2026-08-30
tmax12Znearest30d27 1 QC6.19 [5.65, 6.63]1.01-6.19 [-6.63, -5.65]6.31 [5.75, 6.73]0% [0%, 0%]0%0%-5.19-0.002026-08-02 → 2026-08-30
tmax12Znearest90d27 1 QC6.19 [5.56, 6.76]1.01-6.19 [-6.76, -5.56]6.31 [5.64, 6.84]0% [0%, 0%]0%0%-5.19-0.002026-08-02 → 2026-08-30
tmax12Znearest365d32 1 QC6.48 [5.82, 7.38]1.29-6.48 [-7.38, -5.82]6.67 [5.94, 7.62]0% [0%, 0%]0%0%-1.88+0.442026-01-02 → 2026-08-30
tmax12Znearestall32 1 QC6.48 [5.79, 7.26]1.29-6.48 [-7.26, -5.79]6.67 [5.91, 7.49]0% [0%, 0%]0%0%-1.88+0.442026-01-02 → 2026-08-30
tmin00Zbilinear30d27 1 QC0.96 [0.54, 1.43]0.93+0.36 [-0.24, 1.11]1.24 [0.67, 1.71]67% [43%, 89%]85%100%+0.28+0.322026-08-02 → 2026-08-30
tmin00Zbilinear90d27 1 QC0.96 [0.51, 1.60]0.93+0.36 [-0.25, 1.15]1.24 [0.63, 1.80]67% [35%, 90%]85%100%+0.28+0.322026-08-02 → 2026-08-30
tmin00Zbilinear365d33 1 QC1.56 [0.70, 2.91]1.56+0.84 [-0.10, 2.05]2.56 [0.91, 4.17]58% [25%, 83%]76%91%+0.35+0.372026-01-02 → 2026-08-30
tmin00Zbilinearall33 1 QC1.56 [0.68, 2.77]1.56+0.84 [-0.10, 2.06]2.56 [0.90, 4.01]58% [28%, 83%]76%91%+0.35+0.372026-01-02 → 2026-08-30
tmin00Znearest30d27 1 QC1.03 [0.51, 1.66]0.93+0.66 [0.08, 1.42]1.36 [0.69, 1.91]67% [32%, 93%]81%96%+0.23+0.322026-08-02 → 2026-08-30
tmin00Znearest90d27 1 QC1.03 [0.50, 1.80]0.93+0.66 [0.07, 1.44]1.36 [0.65, 1.97]67% [22%, 93%]81%96%+0.23+0.322026-08-02 → 2026-08-30
tmin00Znearest365d33 1 QC1.63 [0.71, 3.09]1.53+1.09 [0.20, 2.20]2.63 [0.97, 4.24]58% [16%, 85%]73%88%+0.32+0.382026-01-02 → 2026-08-30
tmin00Znearestall33 1 QC1.63 [0.70, 2.90]1.53+1.09 [0.22, 2.23]2.63 [0.94, 4.09]58% [19%, 86%]73%88%+0.32+0.382026-01-02 → 2026-08-30
tmin12Zbilinear30d27 1 QC0.93 [0.66, 1.22]0.91-0.19 [-0.63, 0.35]1.16 [0.82, 1.46]56% [35%, 78%]93%100%+0.30+0.342026-08-02 → 2026-08-30
tmin12Zbilinear90d27 1 QC0.93 [0.62, 1.34]0.91-0.19 [-0.68, 0.36]1.16 [0.72, 1.58]56% [31%, 81%]93%100%+0.30+0.342026-08-02 → 2026-08-30
tmin12Zbilinear365d32 1 QC1.33 [0.73, 2.41]1.35+0.15 [-0.55, 1.11]2.16 [0.91, 3.64]50% [23%, 71%]84%94%+0.43+0.442026-01-02 → 2026-08-30
tmin12Zbilinearall32 1 QC1.33 [0.72, 2.27]1.35+0.15 [-0.55, 1.05]2.16 [0.91, 3.54]50% [26%, 74%]84%94%+0.43+0.442026-01-02 → 2026-08-30
tmin12Znearest30d27 1 QC0.90 [0.56, 1.30]0.90+0.15 [-0.32, 0.71]1.16 [0.69, 1.56]67% [38%, 93%]89%96%+0.32+0.352026-08-02 → 2026-08-30
tmin12Znearest90d27 1 QC0.90 [0.53, 1.46]0.90+0.15 [-0.35, 0.71]1.16 [0.60, 1.65]67% [27%, 100%]89%96%+0.32+0.352026-08-02 → 2026-08-30
tmin12Znearest365d32 1 QC1.33 [0.63, 2.50]1.34+0.44 [-0.23, 1.31]2.19 [0.83, 3.73]59% [20%, 88%]81%91%+0.42+0.442026-01-02 → 2026-08-30
tmin12Znearestall32 1 QC1.33 [0.63, 2.37]1.34+0.44 [-0.23, 1.30]2.19 [0.82, 3.62]59% [25%, 89%]81%91%+0.42+0.442026-01-02 → 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 KSAT, lead day 1, 00Z bilinear tmax+10+50-5-102026-08-02: -4.1 °F2026-08-03: -4.86 °F2026-08-04: -4.31 °F2026-08-05: -3.59 °F2026-08-06: -5.32 °F2026-08-07: -5.17 °F2026-08-08: -4.36 °F2026-08-09: -5.81 °F2026-08-10: -6.13 °F2026-08-11: -5.02 °F2026-08-12: -7.85 °F2026-08-13: -7.73 °F2026-08-14: -6.52 °F2026-08-15: -6.67 °F2026-08-16: -5.01 °F2026-08-17: -4.93 °F2026-08-18: -5.59 °F2026-08-19: -5.73 °F2026-08-20: -7.76 °F2026-08-21: -6.87 °F2026-08-22: -6.31 °F2026-08-23: -6.76 °F2026-08-24: -5.46 °F2026-08-25: -4.84 °F2026-08-26: -4.4 °F2026-08-29: -6.93 °F2026-08-30: -6.28 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-6.28
2026-08-29-6.93
2026-08-28—
2026-08-27—
2026-08-26-4.40
2026-08-25-4.84
2026-08-24-5.46
2026-08-23-6.76
2026-08-22-6.31
2026-08-21-6.87
2026-08-20-7.76
2026-08-19-5.73
2026-08-18-5.59
2026-08-17-4.93
2026-08-16-5.01
2026-08-15-6.67
2026-08-14-6.52
2026-08-13-7.73
2026-08-12-7.85
2026-08-11-5.02
2026-08-10-6.13
2026-08-09-5.81
2026-08-08-4.36
2026-08-07-5.17
2026-08-06-5.32
2026-08-05-3.59
2026-08-04-4.31
2026-08-03-4.86
2026-08-02-4.10

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KSAT, lead day 1-20 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: 2 days-10 to -8 °F: 2 days-8 to -6 °F: 12 days-6 to -4 °F: 16 days-4 to -2 °F: 1 day-2 to 0 °F: 0 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| 5.81 · P90 |e| 8.78 °F-200+20 °Fn = 33 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
-12.00-10.002
-10.00-8.002
-8.00-6.0012
-6.00-4.0016
-4.00-2.001
-2.00+0.000
+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
2026-08275.72 -5.72
2026-0168.29 -8.29

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-02 → 2026-08-30 33
GraphCast (IFS init)2026-01-02 → 2026-08-30 33
GraphCast (IFS init)2026-01-02 → 2026-08-30 32
GraphCast (IFS init)2026-01-02 → 2026-08-30 32

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 27 +2.86 [1.75, 3.74] yes
Aurora (GFS init) 1 -1.53 [-1.53, -1.53] yes
Aurora (IFS init) 2 +0.55 [0.14, 0.97] yes
FourCastNet v2 (GFS init) 1 +2.49 [2.49, 2.49] yes
FourCastNet v2 (IFS init) 2 +3.88 [3.64, 4.12] yes
NCEP GFS 27 +4.14 [3.36, 4.68] yes
GraphCast (GFS init) 1 -1.24 [-1.24, -1.24] yes
ECMWF IFS HRES 21 +3.00 [1.78, 3.89] yes
Pangu-Weather (GFS init) 1 +3.11 [3.11, 3.11] yes
Pangu-Weather (IFS init) 2 +2.66 [2.61, 2.72] yes
Persistence (baseline) 27 +4.72 [4.10, 5.30] yes

Cite this page

ShortCastCheck, KSAT graphcast_ifs lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAT/model/graphcast_ifs/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAT (San Antonio Intl), model graphcast_ifs, lead day 1. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSAT/model/graphcast_ifs/lead/1/

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