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

San Antonio Intl · GraphCast (IFS init) · lead day 5

KSAT · graphcast_ifs · 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, 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
tmax00Zbilinear30d25 1 QC5.49 [3.91, 6.94]1.63-5.49 [-6.94, -3.91]5.87 [4.05, 7.25]0% [0%, 0%]0%12%-1.92+0.162026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC5.49 [3.59, 7.06]1.63-5.49 [-7.06, -3.59]5.87 [3.67, 7.32]0% [0%, 0%]0%12%-1.92+0.162026-08-06 → 2026-08-30
tmax00Zbilinear365d31 1 QC6.12 [4.50, 7.95]2.27-6.12 [-7.95, -4.50]6.73 [4.72, 8.52]0% [0%, 0%]0%10%-0.90+0.312026-01-06 → 2026-08-30
tmax00Zbilinearall31 1 QC6.12 [4.54, 8.00]2.27-6.12 [-8.00, -4.54]6.73 [4.85, 8.61]0% [0%, 0%]0%10%-0.90+0.312026-01-06 → 2026-08-30
tmax00Znearest30d25 1 QC5.16 [3.52, 6.66]1.66-5.16 [-6.66, -3.52]5.58 [3.71, 6.99]0% [0%, 0%]4%12%-1.75+0.142026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC5.16 [3.19, 6.77]1.66-5.16 [-6.77, -3.19]5.58 [3.28, 7.05]0% [0%, 0%]4%12%-1.75+0.142026-08-06 → 2026-08-30
tmax00Znearest365d31 1 QC5.83 [4.12, 7.72]2.31-5.83 [-7.72, -4.12]6.50 [4.37, 8.35]0% [0%, 0%]3%13%-0.81+0.302026-01-06 → 2026-08-30
tmax00Znearestall31 1 QC5.83 [4.20, 7.75]2.31-5.83 [-7.75, -4.20]6.50 [4.52, 8.44]0% [0%, 0%]3%13%-0.81+0.302026-01-06 → 2026-08-30
tmax12Zbilinear30d25 1 QC6.02 [4.38, 7.44]1.60-6.02 [-7.44, -4.38]6.35 [4.63, 7.65]0% [0%, 0%]0%4%-2.20+0.172026-08-06 → 2026-08-30
tmax12Zbilinear90d25 1 QC6.02 [4.05, 7.48]1.60-6.02 [-7.48, -4.05]6.35 [4.27, 7.68]0% [0%, 0%]0%4%-2.20+0.172026-08-06 → 2026-08-30
tmax12Zbilinear365d30 1 QC6.20 [4.69, 7.67]2.00-6.20 [-7.67, -4.69]6.71 [5.03, 8.10]0% [0%, 0%]3%7%-1.35+0.252026-01-06 → 2026-08-30
tmax12Zbilinearall30 1 QC6.20 [4.65, 7.68]2.00-6.20 [-7.68, -4.65]6.71 [5.00, 8.15]0% [0%, 0%]3%7%-1.35+0.252026-01-06 → 2026-08-30
tmax12Znearest30d25 1 QC5.69 [4.00, 7.16]1.64-5.69 [-7.16, -4.00]6.06 [4.28, 7.41]0% [0%, 0%]4%8%-2.03+0.152026-08-06 → 2026-08-30
tmax12Znearest90d25 1 QC5.69 [3.66, 7.22]1.64-5.69 [-7.22, -3.66]6.06 [3.85, 7.43]0% [0%, 0%]4%8%-2.03+0.152026-08-06 → 2026-08-30
tmax12Znearest365d30 1 QC5.91 [4.36, 7.41]2.06-5.91 [-7.41, -4.36]6.48 [4.69, 7.92]0% [0%, 0%]7%13%-1.25+0.232026-01-06 → 2026-08-30
tmax12Znearestall30 1 QC5.91 [4.29, 7.44]2.06-5.91 [-7.44, -4.29]6.48 [4.67, 7.98]0% [0%, 0%]7%13%-1.25+0.232026-01-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC1.35 [0.78, 2.19]1.18+0.88 [0.21, 1.60]1.93 [0.94, 2.94]52% [26%, 73%]80%92%+0.03+0.202026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC1.35 [0.76, 2.51]1.18+0.88 [0.15, 1.74]1.93 [0.96, 3.20]52% [22%, 73%]80%92%+0.03+0.202026-08-06 → 2026-08-30
tmin00Zbilinear365d31 1 QC1.97 [0.89, 3.52]1.71+1.58 [0.44, 3.20]2.79 [1.11, 4.21]42% [10%, 67%]65%77%+0.44+0.532026-01-06 → 2026-08-30
tmin00Zbilinearall31 1 QC1.97 [0.97, 3.62]1.71+1.58 [0.45, 3.45]2.79 [1.17, 4.31]42% [0%, 67%]65%77%+0.44+0.532026-01-06 → 2026-08-30
tmin00Znearest30d25 1 QC1.45 [0.84, 2.30]1.17+1.10 [0.45, 1.80]2.04 [1.03, 3.05]44% [19%, 70%]76%92%-0.04+0.212026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC1.45 [0.84, 2.63]1.17+1.10 [0.40, 1.94]2.04 [1.04, 3.33]44% [12%, 70%]76%92%-0.04+0.212026-08-06 → 2026-08-30
tmin00Znearest365d31 1 QC2.07 [0.99, 3.64]1.69+1.79 [0.66, 3.39]2.90 [1.23, 4.33]35% [7%, 63%]61%74%+0.41+0.532026-01-06 → 2026-08-30
tmin00Znearestall31 1 QC2.07 [1.00, 3.78]1.69+1.79 [0.68, 3.63]2.90 [1.24, 4.47]35% [0%, 62%]61%74%+0.41+0.532026-01-06 → 2026-08-30
tmin12Zbilinear30d25 1 QC1.22 [0.76, 1.87]1.18+0.57 [-0.15, 1.33]1.64 [0.90, 2.40]52% [32%, 73%]80%96%+0.13+0.202026-08-06 → 2026-08-30
tmin12Zbilinear90d25 1 QC1.22 [0.69, 2.11]1.18+0.57 [-0.22, 1.40]1.64 [0.82, 2.58]52% [25%, 78%]80%96%+0.13+0.202026-08-06 → 2026-08-30
tmin12Zbilinear365d30 1 QC1.39 [0.76, 2.13]1.26+0.85 [0.02, 1.80]1.86 [0.93, 2.61]47% [21%, 71%]77%93%+0.53+0.582026-01-06 → 2026-08-30
tmin12Zbilinearall30 1 QC1.39 [0.80, 2.20]1.26+0.85 [-0.02, 1.82]1.86 [0.97, 2.68]47% [21%, 69%]77%93%+0.53+0.582026-01-06 → 2026-08-30
tmin12Znearest30d25 1 QC1.27 [0.77, 1.92]1.18+0.79 [0.09, 1.54]1.72 [0.93, 2.49]44% [24%, 63%]80%96%+0.09+0.202026-08-06 → 2026-08-30
tmin12Znearest90d25 1 QC1.27 [0.72, 2.17]1.18+0.79 [0.01, 1.60]1.72 [0.88, 2.71]44% [18%, 64%]80%96%+0.09+0.202026-08-06 → 2026-08-30
tmin12Znearest365d30 1 QC1.43 [0.82, 2.18]1.25+1.03 [0.24, 1.91]1.93 [0.99, 2.67]40% [17%, 60%]77%93%+0.51+0.582026-01-06 → 2026-08-30
tmin12Znearestall30 1 QC1.43 [0.83, 2.25]1.25+1.03 [0.21, 1.94]1.93 [1.03, 2.75]40% [18%, 61%]77%93%+0.51+0.582026-01-06 → 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 GraphCast (IFS init) at KSAT, lead day 5, 00Z bilinear tmax+10+50-5-102026-08-06: -3.62 °F2026-08-07: -3.69 °F2026-08-08: -2 °F2026-08-09: -4.21 °F2026-08-10: -2.89 °F2026-08-11: -2.96 °F2026-08-12: -4.47 °F2026-08-13: -5.61 °F2026-08-14: -5.87 °F2026-08-15: -6.94 °F2026-08-16: -5.74 °F2026-08-17: -5.65 °F2026-08-18: -5.18 °F2026-08-19: -6.28 °F2026-08-20: -8.32 °F2026-08-21: -8.07 °F2026-08-22: -9.55 °F2026-08-23: -9.61 °F2026-08-24: -9 °F2026-08-25: -5.62 °F2026-08-26: -3.58 °F2026-08-27: -5.42 °F2026-08-28: -4.64 °F2026-08-29: -3.59 °F2026-08-30: -4.85 °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
2026-08-30-4.85
2026-08-29-3.59
2026-08-28-4.64
2026-08-27-5.42
2026-08-26-3.58
2026-08-25-5.62
2026-08-24-9.00
2026-08-23-9.61
2026-08-22-9.55
2026-08-21-8.07
2026-08-20-8.32
2026-08-19-6.28
2026-08-18-5.18
2026-08-17-5.65
2026-08-16-5.74
2026-08-15-6.94
2026-08-14-5.87
2026-08-13-5.61
2026-08-12-4.47
2026-08-11-2.96
2026-08-10-2.89
2026-08-09-4.21
2026-08-08-2.00
2026-08-07-3.69
2026-08-06-3.62

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KSAT, lead day 5-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 2 days-10 to -8 °F: 6 days-8 to -6 °F: 2 days-6 to -4 °F: 12 days-4 to -2 °F: 8 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| 5.61 · P90 |e| 9.61 °F-200+20 °Fn = 31 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
-14.00-12.001
-12.00-10.002
-10.00-8.006
-8.00-6.002
-6.00-4.0012
-4.00-2.008
-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
2026-08255.49 -5.49
2026-0168.74 -8.74

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-06 → 2026-08-30 31
GraphCast (IFS init)2026-01-06 → 2026-08-30 31
GraphCast (IFS init)2026-01-06 → 2026-08-30 30
GraphCast (IFS init)2026-01-06 → 2026-08-30 30

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 25 +2.72 [0.27, 4.09] yes
NCEP GFS 25 +3.60 [0.46, 5.81] yes
ECMWF IFS HRES 18 +3.39 [1.38, 4.97] yes
Persistence (baseline) 25 +3.61 [1.81, 5.04] yes

Cite this page

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

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