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

Austin Bergstrom · GraphCast (IFS init) · lead day 0

KAUS · graphcast_ifs · lead 0

Target day = initialization date + 0 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
tmax00Zbilinear30d28 1 QC7.23 [6.84, 7.56]1.04-7.23 [-7.56, -6.84]7.38 [6.99, 7.72]0% [0%, 0%]4%4%——2026-08-01 → 2026-08-30
tmax00Zbilinear90d28 1 QC7.23 [6.63, 7.84]1.04-7.23 [-7.84, -6.63]7.38 [6.83, 7.98]0% [0%, 0%]4%4%——2026-08-01 → 2026-08-30
tmax00Zbilinear365d34 1 QC7.34 [6.78, 8.00]1.17-7.34 [-8.00, -6.78]7.52 [6.98, 8.16]0% [0%, 0%]3%3%——2026-01-01 → 2026-08-30
tmax00Zbilinearall34 1 QC7.34 [6.73, 7.91]1.17-7.34 [-7.91, -6.73]7.52 [6.95, 8.09]0% [0%, 0%]3%3%——2026-01-01 → 2026-08-30
tmax00Znearest30d28 1 QC6.97 [6.48, 7.36]1.13-6.97 [-7.36, -6.48]7.15 [6.63, 7.58]0% [0%, 0%]4%4%——2026-08-01 → 2026-08-30
tmax00Znearest90d28 1 QC6.97 [6.27, 7.68]1.13-6.97 [-7.68, -6.27]7.15 [6.52, 7.83]0% [0%, 0%]4%4%——2026-08-01 → 2026-08-30
tmax00Znearest365d34 1 QC7.11 [6.46, 7.87]1.27-7.11 [-7.87, -6.46]7.31 [6.67, 8.05]0% [0%, 0%]3%3%——2026-01-01 → 2026-08-30
tmax00Znearestall34 1 QC7.11 [6.43, 7.77]1.27-7.11 [-7.77, -6.43]7.31 [6.64, 8.00]0% [0%, 0%]3%3%——2026-01-01 → 2026-08-30
tmin00Zbilinear30d28 1 QC4.12 [3.19, 5.10]1.93+4.12 [3.19, 5.10]4.73 [3.82, 5.59]11% [0%, 21%]14%43%——2026-08-01 → 2026-08-30
tmin00Zbilinear90d28 1 QC4.12 [3.19, 5.12]1.93+4.12 [3.19, 5.12]4.73 [3.65, 5.62]11% [0%, 21%]14%43%——2026-08-01 → 2026-08-30
tmin00Zbilinear365d34 1 QC5.36 [3.56, 8.06]2.96+5.36 [3.56, 8.06]6.57 [4.19, 9.39]9% [0%, 18%]12%38%——2026-01-01 → 2026-08-30
tmin00Zbilinearall34 1 QC5.36 [3.56, 7.92]2.96+5.36 [3.56, 7.92]6.57 [4.24, 9.18]9% [0%, 19%]12%38%——2026-01-01 → 2026-08-30
tmin00Znearest30d28 1 QC4.27 [3.30, 5.35]1.99+4.27 [3.30, 5.34]4.89 [3.91, 5.89]11% [0%, 21%]11%39%——2026-08-01 → 2026-08-30
tmin00Znearest90d28 1 QC4.27 [3.23, 5.44]1.99+4.27 [3.22, 5.44]4.89 [3.74, 5.92]11% [0%, 21%]11%39%——2026-08-01 → 2026-08-30
tmin00Znearest365d34 1 QC5.49 [3.64, 8.18]2.99+5.48 [3.63, 8.18]6.67 [4.26, 9.42]9% [0%, 18%]9%32%——2026-01-01 → 2026-08-30
tmin00Znearestall34 1 QC5.49 [3.65, 7.95]2.99+5.48 [3.65, 7.95]6.67 [4.31, 9.22]9% [0%, 19%]9%32%——2026-01-01 → 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 KAUS, lead day 0, 00Z bilinear tmax+20+100-10-202026-08-01: -1.82 °F2026-08-02: -7.93 °F2026-08-03: -8.11 °F2026-08-04: -7.23 °F2026-08-05: -6.63 °F2026-08-06: -7.1 °F2026-08-07: -8.15 °F2026-08-08: -7.18 °F2026-08-09: -8.61 °F2026-08-10: -8.1 °F2026-08-11: -7.08 °F2026-08-12: -6.84 °F2026-08-13: -7.83 °F2026-08-14: -6.48 °F2026-08-15: -8.95 °F2026-08-16: -6.55 °F2026-08-17: -8.55 °F2026-08-18: -6.22 °F2026-08-19: -6.01 °F2026-08-20: -7.34 °F2026-08-21: -6.87 °F2026-08-22: -7.91 °F2026-08-23: -6.13 °F2026-08-24: -5.18 °F2026-08-25: -6.55 °F2026-08-28: -9.12 °F2026-08-29: -10.42 °F2026-08-30: -7.41 °F2026-08-012026-08-30°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 (30 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-7.41
2026-08-29-10.42
2026-08-28-9.12
2026-08-27—
2026-08-26—
2026-08-25-6.55
2026-08-24-5.18
2026-08-23-6.13
2026-08-22-7.91
2026-08-21-6.87
2026-08-20-7.34
2026-08-19-6.01
2026-08-18-6.22
2026-08-17-8.55
2026-08-16-6.55
2026-08-15-8.95
2026-08-14-6.48
2026-08-13-7.83
2026-08-12-6.84
2026-08-11-7.08
2026-08-10-8.10
2026-08-09-8.61
2026-08-08-7.18
2026-08-07-8.15
2026-08-06-7.10
2026-08-05-6.63
2026-08-04-7.23
2026-08-03-8.11
2026-08-02-7.93
2026-08-01-1.82

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KAUS, lead day 0-20 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: 9 days-8 to -6 °F: 20 days-6 to -4 °F: 2 days-4 to -2 °F: 0 days-2 to 0 °F: 1 day0 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| 7.22 · P90 |e| 9.07 °F-200+20 °Fn = 34 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
-10.00-8.009
-8.00-6.0020
-6.00-4.002
-4.00-2.000
-2.00+0.001
+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
2026-08287.23 -7.23
2026-0167.88 -7.88

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-01 → 2026-08-30 34
GraphCast (IFS init)2026-01-01 → 2026-08-30 34

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 28 +1.98 [1.13, 2.86] yes
Aurora (GFS init) 2 +1.51 [0.69, 2.34] yes
Aurora (IFS init) 3 +0.39 [0.16, 0.84] yes
FourCastNet v2 (GFS init) 2 +3.72 [2.82, 4.62] yes
FourCastNet v2 (IFS init) 3 +2.73 [1.79, 3.19] yes
NCEP GFS 28 +5.57 [4.85, 6.19] yes
GraphCast (GFS init) 2 +1.99 [0.66, 3.32] yes
ECMWF IFS HRES 22 +2.34 [1.71, 2.99] yes
Pangu-Weather (GFS init) 2 +5.34 [3.45, 7.23] yes
Pangu-Weather (IFS init) 3 +3.86 [2.70, 4.44] yes

Cite this page

ShortCastCheck, KAUS graphcast_ifs lead 0, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KAUS/model/graphcast_ifs/lead/0/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KAUS (Austin Bergstrom), model graphcast_ifs, lead day 0. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KAUS/model/graphcast_ifs/lead/0/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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