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

Austin Bergstrom · GraphCast (IFS init) · lead day 8

KAUS · graphcast_ifs · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 1 QC7.43 [5.71, 8.86]2.07-7.43 [-8.86, -5.71]7.83 [6.16, 9.04]0% [0%, 0%]0%5%-1.82+0.092026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC7.43 [5.50, 8.99]2.07-7.43 [-8.99, -5.50]7.83 [5.89, 9.16]0% [0%, 0%]0%5%-1.82+0.092026-08-09 → 2026-08-30
tmax00Zbilinear365d28 1 QC6.26 [3.51, 8.36]3.23-5.90 [-8.36, -2.51]7.03 [4.26, 8.67]7% [0%, 27%]14%21%-0.25+0.412026-01-09 → 2026-08-30
tmax00Zbilinearall28 1 QC6.26 [3.11, 8.35]3.23-5.90 [-8.34, -1.80]7.03 [3.88, 8.66]7% [0%, 29%]14%21%-0.25+0.412026-01-09 → 2026-08-30
tmax00Znearest30d22 1 QC7.47 [5.78, 8.87]2.07-7.47 [-8.87, -5.78]7.86 [6.25, 9.06]0% [0%, 0%]0%5%-1.83+0.092026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC7.47 [5.56, 9.01]2.07-7.47 [-9.01, -5.56]7.86 [5.96, 9.17]0% [0%, 0%]0%5%-1.83+0.092026-08-09 → 2026-08-30
tmax00Znearest365d28 1 QC6.27 [3.50, 8.34]3.25-5.92 [-8.34, -2.49]7.06 [4.35, 8.67]7% [0%, 27%]14%21%-0.25+0.412026-01-09 → 2026-08-30
tmax00Znearestall28 1 QC6.27 [3.09, 8.37]3.25-5.92 [-8.37, -1.79]7.06 [3.93, 8.67]7% [0%, 29%]14%21%-0.25+0.412026-01-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC7.83 [6.11, 9.26]1.93-7.83 [-9.26, -6.11]8.16 [6.38, 9.43]0% [0%, 0%]0%0%-1.97+0.152026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC7.83 [5.79, 9.41]1.93-7.83 [-9.41, -5.79]8.16 [5.98, 9.53]0% [0%, 0%]0%0%-1.97+0.152026-08-09 → 2026-08-30
tmax12Zbilinear365d27 1 QC7.42 [5.54, 8.99]2.49-7.10 [-8.83, -4.74]7.87 [6.05, 9.18]4% [0%, 15%]4%4%-0.60+0.502026-01-09 → 2026-08-30
tmax12Zbilinearall27 1 QC7.42 [5.61, 8.93]2.49-7.10 [-8.82, -4.54]7.87 [6.08, 9.18]4% [0%, 16%]4%4%-0.60+0.502026-01-09 → 2026-08-30
tmax12Znearest30d22 1 QC7.87 [6.19, 9.28]1.91-7.87 [-9.28, -6.19]8.19 [6.46, 9.42]0% [0%, 0%]0%0%-1.99+0.162026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC7.87 [5.86, 9.41]1.91-7.87 [-9.41, -5.86]8.19 [6.10, 9.53]0% [0%, 0%]0%0%-1.99+0.162026-08-09 → 2026-08-30
tmax12Znearest365d27 1 QC7.46 [5.64, 8.98]2.46-7.12 [-8.82, -4.72]7.89 [6.10, 9.19]4% [0%, 15%]4%4%-0.61+0.512026-01-09 → 2026-08-30
tmax12Znearestall27 1 QC7.46 [5.64, 8.94]2.46-7.12 [-8.81, -4.59]7.89 [6.15, 9.17]4% [0%, 16%]4%4%-0.61+0.512026-01-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC4.77 [3.89, 5.67]1.95+4.76 [3.87, 5.67]5.34 [4.50, 6.15]5% [0%, 12%]9%32%-0.67+0.322026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC4.77 [3.78, 5.81]1.95+4.76 [3.77, 5.81]5.34 [4.41, 6.29]5% [0%, 13%]9%32%-0.67+0.322026-08-09 → 2026-08-30
tmin00Zbilinear365d28 1 QC4.97 [4.12, 6.01]2.40+4.69 [3.79, 5.83]5.65 [4.81, 6.71]7% [0%, 16%]11%29%-0.14+0.452026-01-09 → 2026-08-30
tmin00Zbilinearall28 1 QC4.97 [4.11, 5.89]2.40+4.69 [3.79, 5.61]5.65 [4.81, 6.68]7% [0%, 16%]11%29%-0.14+0.452026-01-09 → 2026-08-30
tmin00Znearest30d22 1 QC4.66 [3.77, 5.57]1.96+4.64 [3.72, 5.57]5.24 [4.38, 6.06]5% [0%, 12%]14%32%-0.63+0.322026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC4.66 [3.64, 5.73]1.96+4.64 [3.61, 5.73]5.24 [4.30, 6.22]5% [0%, 13%]14%32%-0.63+0.322026-08-09 → 2026-08-30
tmin00Znearest365d28 1 QC4.88 [4.03, 5.97]2.39+4.60 [3.71, 5.73]5.55 [4.71, 6.58]7% [0%, 16%]14%29%-0.12+0.452026-01-09 → 2026-08-30
tmin00Znearestall28 1 QC4.88 [4.01, 5.82]2.39+4.60 [3.70, 5.50]5.55 [4.70, 6.60]7% [0%, 16%]14%29%-0.12+0.452026-01-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC4.46 [3.64, 5.23]1.82+4.46 [3.64, 5.23]4.97 [4.20, 5.57]0% [0%, 0%]18%27%-0.56+0.372026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC4.46 [3.59, 5.24]1.82+4.46 [3.59, 5.24]4.97 [4.09, 5.58]0% [0%, 0%]18%27%-0.56+0.372026-08-09 → 2026-08-30
tmin12Zbilinear365d27 1 QC4.38 [3.54, 5.25]2.42+3.95 [2.29, 5.23]5.05 [4.17, 5.89]4% [0%, 14%]22%33%-0.07+0.412026-01-09 → 2026-08-30
tmin12Zbilinearall27 1 QC4.38 [3.50, 5.12]2.42+3.95 [2.11, 5.11]5.05 [4.12, 5.79]4% [0%, 15%]22%33%-0.07+0.412026-01-09 → 2026-08-30
tmin12Znearest30d22 1 QC4.34 [3.50, 5.12]1.83+4.34 [3.50, 5.12]4.86 [4.07, 5.46]9% [0%, 16%]18%32%-0.52+0.362026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC4.34 [3.44, 5.14]1.83+4.34 [3.44, 5.14]4.86 [3.99, 5.49]9% [0%, 14%]18%32%-0.52+0.362026-08-09 → 2026-08-30
tmin12Znearest365d27 1 QC4.24 [3.36, 5.09]2.41+3.82 [2.14, 5.08]4.90 [4.01, 5.70]11% [0%, 20%]22%37%-0.04+0.412026-01-09 → 2026-08-30
tmin12Znearestall27 1 QC4.24 [3.35, 5.02]2.41+3.82 [1.94, 4.99]4.90 [3.94, 5.59]11% [0%, 20%]22%37%-0.04+0.412026-01-09 → 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 8, 00Z bilinear tmax+20+100-10-202026-08-09: -3.92 °F2026-08-10: -8.56 °F2026-08-11: -4.25 °F2026-08-12: -3.94 °F2026-08-13: -4.52 °F2026-08-14: -2.59 °F2026-08-15: -9.67 °F2026-08-16: -8.44 °F2026-08-17: -8.95 °F2026-08-18: -8.47 °F2026-08-19: -9.61 °F2026-08-20: -6.93 °F2026-08-21: -7.72 °F2026-08-22: -11.46 °F2026-08-23: -10.83 °F2026-08-24: -10.65 °F2026-08-25: -8.94 °F2026-08-26: -8.54 °F2026-08-27: -5.94 °F2026-08-28: -7.49 °F2026-08-29: -4.6 °F2026-08-30: -7.49 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-7.49
2026-08-29-4.60
2026-08-28-7.49
2026-08-27-5.94
2026-08-26-8.54
2026-08-25-8.94
2026-08-24-10.65
2026-08-23-10.83
2026-08-22-11.46
2026-08-21-7.72
2026-08-20-6.93
2026-08-19-9.61
2026-08-18-8.47
2026-08-17-8.95
2026-08-16-8.44
2026-08-15-9.67
2026-08-14-2.59
2026-08-13-4.52
2026-08-12-3.94
2026-08-11-4.25
2026-08-10-8.56
2026-08-09-3.92

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KAUS, lead day 8-20 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: 3 days-10 to -8 °F: 8 days-8 to -6 °F: 4 days-6 to -4 °F: 4 days-4 to -2 °F: 4 days-2 to 0 °F: 3 days0 to 2 °F: 1 day2 to 4 °F: 0 days4 to 6 °F: 1 day6 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| 7.21 · P90 |e| 9.96 °F-200+20 °Fn = 28 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
-12.00-10.003
-10.00-8.008
-8.00-6.004
-6.00-4.004
-4.00-2.004
-2.00+0.003
+0.00+2.001
+2.00+4.000
+4.00+6.001
+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
2026-08227.43 -7.43
2026-0161.94 -0.28

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 27
GraphCast (IFS init)2026-01-09 → 2026-08-30 27

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 22 +2.76 [1.06, 3.82] yes
NCEP GFS 22 +5.12 [4.09, 6.14] yes
ECMWF IFS HRES 17 +4.12 [2.05, 4.77] yes
Persistence (baseline) 22 +4.80 [2.78, 6.20] yes

Cite this page

ShortCastCheck, KAUS graphcast_ifs lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KAUS/model/graphcast_ifs/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KAUS (Austin Bergstrom), model graphcast_ifs, lead day 8. 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/8/

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