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

San Antonio Intl · GraphCast (IFS init) · lead day 2

KSAT · graphcast_ifs · lead 2

Target day = initialization date + 2 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
tmax00Zbilinear30d26 1 QC5.69 [4.59, 6.43]1.32-5.69 [-6.43, -4.59]5.90 [4.74, 6.57]0% [0%, 0%]0%4%-3.11+0.052026-08-03 → 2026-08-30
tmax00Zbilinear90d26 1 QC5.69 [4.32, 6.47]1.32-5.69 [-6.47, -4.32]5.90 [4.42, 6.58]0% [0%, 0%]0%4%-3.11+0.052026-08-03 → 2026-08-30
tmax00Zbilinear365d32 1 QC6.02 [4.98, 6.94]1.51-6.02 [-6.94, -4.98]6.31 [5.19, 7.24]0% [0%, 0%]0%3%-1.14+0.472026-01-03 → 2026-08-30
tmax00Zbilinearall32 1 QC6.02 [4.90, 6.94]1.51-6.02 [-6.94, -4.90]6.31 [5.15, 7.19]0% [0%, 0%]0%3%-1.14+0.472026-01-03 → 2026-08-30
tmax00Znearest30d26 1 QC5.31 [4.21, 6.07]1.33-5.31 [-6.07, -4.21]5.55 [4.41, 6.23]0% [0%, 0%]0%4%-2.84+0.042026-08-03 → 2026-08-30
tmax00Znearest90d26 1 QC5.31 [3.92, 6.12]1.33-5.31 [-6.12, -3.92]5.55 [4.05, 6.24]0% [0%, 0%]0%4%-2.84+0.042026-08-03 → 2026-08-30
tmax00Znearest365d32 1 QC5.70 [4.60, 6.71]1.57-5.70 [-6.71, -4.60]6.02 [4.84, 7.04]0% [0%, 0%]0%3%-1.02+0.452026-01-03 → 2026-08-30
tmax00Znearestall32 1 QC5.70 [4.56, 6.68]1.57-5.70 [-6.68, -4.56]6.02 [4.80, 6.98]0% [0%, 0%]0%3%-1.02+0.452026-01-03 → 2026-08-30
tmax12Zbilinear30d26 1 QC6.59 [5.81, 7.20]1.08-6.59 [-7.20, -5.81]6.73 [5.95, 7.30]0% [0%, 0%]0%0%-3.76+0.222026-08-03 → 2026-08-30
tmax12Zbilinear90d26 1 QC6.59 [5.65, 7.27]1.08-6.59 [-7.27, -5.65]6.73 [5.70, 7.34]0% [0%, 0%]0%0%-3.76+0.222026-08-03 → 2026-08-30
tmax12Zbilinear365d31 1 QC6.89 [5.98, 7.82]1.31-6.89 [-7.82, -5.98]7.08 [6.12, 8.01]0% [0%, 0%]0%0%-1.57+0.512026-01-03 → 2026-08-30
tmax12Zbilinearall31 1 QC6.89 [6.03, 7.81]1.31-6.89 [-7.81, -6.03]7.08 [6.21, 8.01]0% [0%, 0%]0%0%-1.57+0.512026-01-03 → 2026-08-30
tmax12Znearest30d26 1 QC6.20 [5.39, 6.83]1.09-6.20 [-6.83, -5.39]6.35 [5.55, 6.93]0% [0%, 0%]0%0%-3.48+0.212026-08-03 → 2026-08-30
tmax12Znearest90d26 1 QC6.20 [5.24, 6.91]1.09-6.20 [-6.91, -5.24]6.35 [5.28, 6.98]0% [0%, 0%]0%0%-3.48+0.212026-08-03 → 2026-08-30
tmax12Znearest365d31 1 QC6.54 [5.58, 7.55]1.36-6.54 [-7.55, -5.58]6.76 [5.73, 7.81]0% [0%, 0%]0%0%-1.44+0.492026-01-03 → 2026-08-30
tmax12Znearestall31 1 QC6.54 [5.65, 7.55]1.36-6.54 [-7.55, -5.65]6.76 [5.83, 7.76]0% [0%, 0%]0%0%-1.44+0.492026-01-03 → 2026-08-30
tmin00Zbilinear30d26 1 QC1.03 [0.71, 1.41]1.02+0.30 [-0.26, 0.91]1.25 [0.84, 1.61]62% [45%, 78%]88%100%+0.25+0.292026-08-03 → 2026-08-30
tmin00Zbilinear90d26 1 QC1.03 [0.72, 1.51]1.02+0.30 [-0.33, 0.98]1.25 [0.86, 1.66]62% [43%, 79%]88%100%+0.25+0.292026-08-03 → 2026-08-30
tmin00Zbilinear365d32 1 QC1.64 [0.83, 2.93]1.56+1.04 [-0.04, 2.65]2.56 [0.98, 4.14]50% [19%, 71%]81%91%+0.29+0.352026-01-03 → 2026-08-30
tmin00Zbilinearall32 1 QC1.64 [0.83, 2.90]1.56+1.04 [-0.07, 2.63]2.56 [1.00, 4.06]50% [22%, 71%]81%91%+0.29+0.352026-01-03 → 2026-08-30
tmin00Znearest30d26 1 QC1.08 [0.68, 1.54]1.02+0.56 [0.01, 1.16]1.34 [0.86, 1.77]46% [20%, 73%]88%100%+0.22+0.292026-08-03 → 2026-08-30
tmin00Znearest90d26 1 QC1.08 [0.67, 1.62]1.02+0.56 [-0.06, 1.23]1.34 [0.85, 1.79]46% [15%, 74%]88%100%+0.22+0.292026-08-03 → 2026-08-30
tmin00Znearest365d32 1 QC1.69 [0.86, 2.99]1.49+1.27 [0.23, 2.80]2.60 [1.05, 4.16]38% [7%, 66%]81%91%+0.27+0.372026-01-03 → 2026-08-30
tmin00Znearestall32 1 QC1.69 [0.84, 2.97]1.49+1.27 [0.20, 2.78]2.60 [1.04, 4.08]38% [8%, 65%]81%91%+0.27+0.372026-01-03 → 2026-08-30
tmin12Zbilinear30d26 1 QC0.88 [0.68, 1.07]0.86-0.23 [-0.73, 0.30]1.06 [0.83, 1.27]62% [45%, 83%]96%100%+0.36+0.402026-08-03 → 2026-08-30
tmin12Zbilinear90d26 1 QC0.88 [0.64, 1.14]0.86-0.23 [-0.78, 0.35]1.06 [0.75, 1.35]62% [43%, 88%]96%100%+0.36+0.402026-08-03 → 2026-08-30
tmin12Zbilinear365d31 1 QC1.32 [0.76, 2.46]1.36+0.39 [-0.56, 1.94]2.31 [0.91, 3.93]58% [39%, 77%]90%94%+0.42+0.432026-01-03 → 2026-08-30
tmin12Zbilinearall31 1 QC1.32 [0.76, 2.29]1.36+0.39 [-0.58, 1.81]2.31 [0.90, 3.82]58% [39%, 77%]90%94%+0.42+0.432026-01-03 → 2026-08-30
tmin12Znearest30d26 1 QC0.87 [0.64, 1.12]0.87+0.05 [-0.45, 0.58]1.05 [0.75, 1.31]69% [50%, 88%]92%100%+0.37+0.392026-08-03 → 2026-08-30
tmin12Znearest90d26 1 QC0.87 [0.58, 1.18]0.87+0.05 [-0.50, 0.62]1.05 [0.65, 1.39]69% [45%, 90%]92%100%+0.37+0.392026-08-03 → 2026-08-30
tmin12Znearest365d31 1 QC1.32 [0.71, 2.47]1.34+0.63 [-0.30, 2.10]2.30 [0.83, 3.93]65% [40%, 86%]87%94%+0.42+0.442026-01-03 → 2026-08-30
tmin12Znearestall31 1 QC1.32 [0.70, 2.30]1.34+0.63 [-0.30, 1.97]2.30 [0.84, 3.83]65% [41%, 85%]87%94%+0.42+0.442026-01-03 → 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 2, 00Z bilinear tmax+10+50-5-102026-08-03: -3.42 °F2026-08-04: -4.85 °F2026-08-05: -3.43 °F2026-08-06: -4.1 °F2026-08-07: -4.69 °F2026-08-08: -2.79 °F2026-08-09: -6.27 °F2026-08-10: -5.13 °F2026-08-11: -4.77 °F2026-08-12: -6.04 °F2026-08-13: -9.67 °F2026-08-14: -6.63 °F2026-08-15: -7.17 °F2026-08-16: -4.39 °F2026-08-17: -5.17 °F2026-08-18: -6.58 °F2026-08-19: -6.25 °F2026-08-20: -7.46 °F2026-08-21: -7.22 °F2026-08-22: -7.54 °F2026-08-23: -7.24 °F2026-08-24: -6.8 °F2026-08-25: -5.04 °F2026-08-26: -3.57 °F2026-08-27: -6.2 °F2026-08-30: -5.44 °F2026-08-032026-08-30°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 (28 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-5.44
2026-08-29—
2026-08-28—
2026-08-27-6.20
2026-08-26-3.57
2026-08-25-5.04
2026-08-24-6.80
2026-08-23-7.24
2026-08-22-7.54
2026-08-21-7.22
2026-08-20-7.46
2026-08-19-6.25
2026-08-18-6.58
2026-08-17-5.17
2026-08-16-4.39
2026-08-15-7.17
2026-08-14-6.63
2026-08-13-9.67
2026-08-12-6.04
2026-08-11-4.77
2026-08-10-5.13
2026-08-09-6.27
2026-08-08-2.79
2026-08-07-4.69
2026-08-06-4.10
2026-08-05-3.43
2026-08-04-4.85
2026-08-03-3.42

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KSAT, lead day 2-20 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: 3 days-8 to -6 °F: 13 days-6 to -4 °F: 11 days-4 to -2 °F: 4 days-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| 6.12 · P90 |e| 8.42 °F-200+20 °Fn = 32 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
-10.00-8.003
-8.00-6.0013
-6.00-4.0011
-4.00-2.004
-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
2026-08265.69 -5.69
2026-0167.49 -7.49

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-03 → 2026-08-30 32
GraphCast (IFS init)2026-01-03 → 2026-08-30 32
GraphCast (IFS init)2026-01-03 → 2026-08-30 31
GraphCast (IFS init)2026-01-03 → 2026-08-30 31

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 26 +2.72 [1.61, 3.60] yes
Aurora (IFS init) 1 +0.80 [0.80, 0.80] yes
FourCastNet v2 (IFS init) 1 +3.77 [3.77, 3.77] yes
NCEP GFS 26 +3.90 [2.24, 5.11] yes
ECMWF IFS HRES 20 +3.01 [1.79, 4.14] yes
Pangu-Weather (IFS init) 1 +1.23 [1.23, 1.23] yes
Persistence (baseline) 26 +4.30 [3.23, 5.13] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAT (San Antonio Intl), model graphcast_ifs, lead day 2. 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/2/

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