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

Austin Bergstrom · GraphCast (IFS init) · lead day 1

KAUS · 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 QC7.51 [7.15, 7.94]1.07-7.51 [-7.94, -7.15]7.62 [7.27, 8.06]0% [0%, 0%]0%0%-3.94+0.312026-08-02 → 2026-08-30
tmax00Zbilinear90d27 1 QC7.51 [7.17, 8.04]1.07-7.51 [-8.04, -7.17]7.62 [7.27, 8.18]0% [0%, 0%]0%0%-3.94+0.312026-08-02 → 2026-08-30
tmax00Zbilinear365d33 1 QC7.72 [7.26, 8.40]1.20-7.72 [-8.40, -7.26]7.86 [7.37, 8.55]0% [0%, 0%]0%0%-1.86+0.562026-01-02 → 2026-08-30
tmax00Zbilinearall33 1 QC7.72 [7.23, 8.37]1.20-7.72 [-8.37, -7.23]7.86 [7.33, 8.55]0% [0%, 0%]0%0%-1.86+0.562026-01-02 → 2026-08-30
tmax00Znearest30d27 1 QC7.37 [6.98, 7.84]1.07-7.37 [-7.84, -6.98]7.48 [7.08, 7.97]0% [0%, 0%]0%0%-3.85+0.312026-08-02 → 2026-08-30
tmax00Znearest90d27 1 QC7.37 [7.00, 7.93]1.07-7.37 [-7.93, -7.00]7.48 [7.11, 8.08]0% [0%, 0%]0%0%-3.85+0.312026-08-02 → 2026-08-30
tmax00Znearest365d33 1 QC7.60 [7.08, 8.34]1.23-7.60 [-8.34, -7.08]7.75 [7.20, 8.52]0% [0%, 0%]0%0%-1.82+0.552026-01-02 → 2026-08-30
tmax00Znearestall33 1 QC7.60 [7.07, 8.33]1.23-7.60 [-8.33, -7.07]7.75 [7.16, 8.52]0% [0%, 0%]0%0%-1.82+0.552026-01-02 → 2026-08-30
tmax12Zbilinear30d27 1 QC8.57 [8.14, 9.18]1.09-8.57 [-9.18, -8.14]8.67 [8.23, 9.28]0% [0%, 0%]0%0%-4.64+0.302026-08-02 → 2026-08-30
tmax12Zbilinear90d27 1 QC8.57 [8.17, 9.31]1.09-8.57 [-9.31, -8.17]8.67 [8.24, 9.42]0% [0%, 0%]0%0%-4.64+0.302026-08-02 → 2026-08-30
tmax12Zbilinear365d32 1 QC8.67 [8.25, 9.34]1.23-8.67 [-9.34, -8.25]8.79 [8.33, 9.48]0% [0%, 0%]0%0%-2.26+0.552026-01-02 → 2026-08-30
tmax12Zbilinearall32 1 QC8.67 [8.21, 9.34]1.23-8.67 [-9.34, -8.21]8.79 [8.31, 9.50]0% [0%, 0%]0%0%-2.26+0.552026-01-02 → 2026-08-30
tmax12Znearest30d27 1 QC8.46 [8.04, 9.12]1.12-8.46 [-9.12, -8.04]8.57 [8.11, 9.24]0% [0%, 0%]0%0%-4.57+0.282026-08-02 → 2026-08-30
tmax12Znearest90d27 1 QC8.46 [8.08, 9.22]1.12-8.46 [-9.22, -8.08]8.57 [8.15, 9.35]0% [0%, 0%]0%0%-4.57+0.282026-08-02 → 2026-08-30
tmax12Znearest365d32 1 QC8.57 [8.13, 9.30]1.29-8.57 [-9.30, -8.13]8.70 [8.22, 9.44]0% [0%, 0%]0%0%-2.22+0.532026-01-02 → 2026-08-30
tmax12Znearestall32 1 QC8.57 [8.09, 9.29]1.29-8.57 [-9.29, -8.09]8.70 [8.17, 9.46]0% [0%, 0%]0%0%-2.22+0.532026-01-02 → 2026-08-30
tmin00Zbilinear30d27 1 QC4.49 [3.45, 5.46]1.79+4.45 [3.41, 5.41]4.95 [4.01, 5.77]7% [0%, 15%]15%22%-0.66+0.342026-08-02 → 2026-08-30
tmin00Zbilinear90d27 1 QC4.49 [3.44, 5.57]1.79+4.45 [3.40, 5.54]4.95 [3.99, 5.86]7% [0%, 15%]15%22%-0.66+0.342026-08-02 → 2026-08-30
tmin00Zbilinear365d33 1 QC5.58 [3.90, 8.12]2.67+5.55 [3.86, 8.09]6.60 [4.47, 9.28]6% [0%, 14%]15%21%-0.41+0.332026-01-02 → 2026-08-30
tmin00Zbilinearall33 1 QC5.58 [3.91, 8.01]2.67+5.55 [3.88, 7.97]6.60 [4.46, 9.07]6% [0%, 14%]15%21%-0.41+0.332026-01-02 → 2026-08-30
tmin00Znearest30d27 1 QC4.53 [3.44, 5.56]1.81+4.48 [3.39, 5.52]5.00 [4.02, 5.90]7% [0%, 15%]15%19%-0.67+0.332026-08-02 → 2026-08-30
tmin00Znearest90d27 1 QC4.53 [3.42, 5.69]1.81+4.48 [3.39, 5.67]5.00 [3.97, 5.98]7% [0%, 15%]15%19%-0.67+0.332026-08-02 → 2026-08-30
tmin00Znearest365d33 1 QC5.58 [3.90, 8.09]2.64+5.55 [3.85, 8.09]6.56 [4.46, 9.11]6% [0%, 14%]15%18%-0.41+0.342026-01-02 → 2026-08-30
tmin00Znearestall33 1 QC5.58 [3.91, 7.89]2.64+5.55 [3.86, 7.88]6.56 [4.44, 8.94]6% [0%, 14%]15%18%-0.41+0.342026-01-02 → 2026-08-30
tmin12Zbilinear30d27 1 QC3.76 [2.95, 4.41]1.68+3.64 [2.83, 4.33]4.18 [3.46, 4.74]4% [0%, 11%]19%37%-0.39+0.382026-08-02 → 2026-08-30
tmin12Zbilinear90d27 1 QC3.76 [2.95, 4.51]1.68+3.64 [2.82, 4.42]4.18 [3.42, 4.82]4% [0%, 11%]19%37%-0.39+0.382026-08-02 → 2026-08-30
tmin12Zbilinear365d32 1 QC4.70 [3.27, 7.11]2.57+4.60 [3.15, 7.05]5.74 [3.75, 8.45]3% [0%, 9%]19%34%-0.17+0.362026-01-02 → 2026-08-30
tmin12Zbilinearall32 1 QC4.70 [3.32, 6.95]2.57+4.60 [3.17, 6.84]5.74 [3.81, 8.28]3% [0%, 9%]19%34%-0.17+0.362026-01-02 → 2026-08-30
tmin12Znearest30d27 1 QC3.78 [2.92, 4.47]1.73+3.65 [2.77, 4.38]4.21 [3.46, 4.81]7% [0%, 20%]22%44%-0.40+0.362026-08-02 → 2026-08-30
tmin12Znearest90d27 1 QC3.78 [2.92, 4.57]1.73+3.65 [2.76, 4.49]4.21 [3.41, 4.88]7% [0%, 19%]22%44%-0.40+0.362026-08-02 → 2026-08-30
tmin12Znearest365d32 1 QC4.71 [3.25, 7.09]2.59+4.61 [3.14, 7.08]5.74 [3.76, 8.41]6% [0%, 18%]22%41%-0.18+0.362026-01-02 → 2026-08-30
tmin12Znearestall32 1 QC4.71 [3.30, 6.97]2.59+4.61 [3.13, 6.87]5.74 [3.80, 8.24]6% [0%, 18%]22%41%-0.18+0.362026-01-02 → 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 KAUS, lead day 1, 00Z bilinear tmax+20+100-10-202026-08-02: -6.88 °F2026-08-03: -9.68 °F2026-08-04: -7.01 °F2026-08-05: -5.39 °F2026-08-06: -7.39 °F2026-08-07: -6.46 °F2026-08-08: -7.29 °F2026-08-09: -8.41 °F2026-08-10: -8.06 °F2026-08-11: -8.08 °F2026-08-12: -7.72 °F2026-08-13: -6.85 °F2026-08-14: -6.04 °F2026-08-15: -9.36 °F2026-08-16: -6.82 °F2026-08-17: -8.56 °F2026-08-18: -7.81 °F2026-08-19: -6.09 °F2026-08-20: -7.86 °F2026-08-21: -7.98 °F2026-08-22: -9.54 °F2026-08-23: -6.71 °F2026-08-24: -6.03 °F2026-08-25: -6.13 °F2026-08-26: -5.56 °F2026-08-29: -8.4 °F2026-08-30: -10.58 °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
2026-08-30-10.58
2026-08-29-8.40
2026-08-28—
2026-08-27—
2026-08-26-5.56
2026-08-25-6.13
2026-08-24-6.03
2026-08-23-6.71
2026-08-22-9.54
2026-08-21-7.98
2026-08-20-7.86
2026-08-19-6.09
2026-08-18-7.81
2026-08-17-8.56
2026-08-16-6.82
2026-08-15-9.36
2026-08-14-6.04
2026-08-13-6.85
2026-08-12-7.72
2026-08-11-8.08
2026-08-10-8.06
2026-08-09-8.41
2026-08-08-7.29
2026-08-07-6.46
2026-08-06-7.39
2026-08-05-5.39
2026-08-04-7.01
2026-08-03-9.68
2026-08-02-6.88

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KAUS, 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: 11 days-8 to -6 °F: 17 days-6 to -4 °F: 3 days-4 to -2 °F: 0 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| 7.72 · P90 |e| 9.61 °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
-10.00-8.0011
-8.00-6.0017
-6.00-4.003
-4.00-2.000
-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
2026-08277.51 -7.51
2026-0168.68 -8.68

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 +2.37 [1.45, 3.47] yes
Aurora (GFS init) 1 +1.21 [1.21, 1.21] yes
Aurora (IFS init) 2 +1.74 [1.50, 1.98] yes
FourCastNet v2 (GFS init) 1 +5.09 [5.09, 5.09] yes
FourCastNet v2 (IFS init) 2 +4.74 [3.96, 5.52] yes
NCEP GFS 27 +6.12 [5.64, 6.62] yes
GraphCast (GFS init) 1 +1.95 [1.95, 1.95] yes
ECMWF IFS HRES 21 +2.82 [2.25, 3.57] yes
Pangu-Weather (GFS init) 1 +6.14 [6.14, 6.14] yes
Pangu-Weather (IFS init) 2 +3.58 [2.64, 4.52] yes
Persistence (baseline) 27 +5.99 [5.49, 6.72] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KAUS (Austin Bergstrom), 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/KAUS/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