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

Austin Bergstrom · GraphCast (IFS init) · lead day 9

KAUS · graphcast_ifs · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d21 1 QC7.49 [5.92, 8.68]2.19-7.49 [-8.68, -5.92]7.94 [6.66, 8.84]0% [0%, 0%]0%10%-2.21-0.162026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC7.49 [5.66, 8.74]2.19-7.49 [-8.74, -5.66]7.94 [6.46, 8.94]0% [0%, 0%]0%10%-2.21-0.162026-08-10 → 2026-08-30
tmax00Zbilinear365d27 1 QC7.56 [5.93, 8.94]4.38-5.84 [-8.27, -1.76]8.16 [6.67, 9.45]0% [0%, 0%]0%11%-0.50+0.232026-01-10 → 2026-08-30
tmax00Zbilinearall27 1 QC7.56 [5.94, 8.88]4.38-5.84 [-8.17, -1.65]8.16 [6.66, 9.41]0% [0%, 0%]0%11%-0.50+0.232026-01-10 → 2026-08-30
tmax00Znearest30d21 1 QC7.54 [6.01, 8.70]2.24-7.54 [-8.70, -6.01]8.01 [6.78, 8.88]0% [0%, 0%]0%10%-2.23-0.192026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC7.54 [5.80, 8.80]2.24-7.54 [-8.80, -5.80]8.01 [6.64, 8.96]0% [0%, 0%]0%10%-2.23-0.192026-08-10 → 2026-08-30
tmax00Znearest365d27 1 QC7.61 [6.04, 8.90]4.42-5.86 [-8.31, -1.70]8.19 [6.81, 9.38]0% [0%, 0%]0%11%-0.51+0.222026-01-10 → 2026-08-30
tmax00Znearestall27 1 QC7.61 [6.06, 8.88]4.42-5.86 [-8.23, -1.62]8.19 [6.80, 9.34]0% [0%, 0%]0%11%-0.51+0.222026-01-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC7.79 [6.07, 9.21]1.98-7.79 [-9.21, -6.07]8.16 [6.41, 9.34]0% [0%, 0%]5%5%-2.34-0.052026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC7.79 [5.64, 9.27]1.98-7.79 [-9.27, -5.64]8.16 [5.84, 9.41]0% [0%, 0%]5%5%-2.34-0.052026-08-10 → 2026-08-30
tmax12Zbilinear365d26 1 QC7.22 [5.09, 8.84]3.33-6.68 [-8.75, -3.24]7.93 [6.04, 9.10]0% [0%, 0%]12%15%-0.58+0.352026-01-10 → 2026-08-30
tmax12Zbilinearall26 1 QC7.22 [5.02, 8.78]3.33-6.68 [-8.70, -3.00]7.93 [6.21, 9.10]0% [0%, 0%]12%15%-0.58+0.352026-01-10 → 2026-08-30
tmax12Znearest30d21 1 QC7.85 [6.16, 9.23]1.95-7.85 [-9.23, -6.16]8.22 [6.50, 9.36]0% [0%, 0%]5%5%-2.37-0.032026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC7.85 [5.73, 9.30]1.95-7.85 [-9.30, -5.73]8.22 [5.93, 9.43]0% [0%, 0%]5%5%-2.37-0.032026-08-10 → 2026-08-30
tmax12Znearest365d26 1 QC7.32 [5.25, 8.89]3.36-6.72 [-8.80, -3.24]7.99 [6.15, 9.13]0% [0%, 0%]12%12%-0.60+0.342026-01-10 → 2026-08-30
tmax12Znearestall26 1 QC7.32 [5.20, 8.83]3.36-6.72 [-8.74, -2.98]7.99 [6.32, 9.11]0% [0%, 0%]12%12%-0.60+0.342026-01-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC4.54 [3.56, 5.82]2.05+4.54 [3.56, 5.82]5.19 [3.96, 6.43]10% [0%, 18%]14%33%-0.59+0.282026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC4.54 [3.43, 6.03]2.05+4.54 [3.43, 6.03]5.19 [3.90, 6.74]10% [0%, 17%]14%33%-0.59+0.282026-08-10 → 2026-08-30
tmin00Zbilinear365d27 1 QC5.74 [3.96, 8.84]3.48+5.46 [3.92, 8.36]7.33 [4.53, 11.03]7% [0%, 14%]15%30%-0.12+0.322026-01-10 → 2026-08-30
tmin00Zbilinearall27 1 QC5.74 [4.05, 9.06]3.48+5.46 [4.04, 8.13]7.33 [4.62, 11.24]7% [0%, 15%]15%30%-0.12+0.322026-01-10 → 2026-08-30
tmin00Znearest30d21 1 QC4.42 [3.40, 5.72]2.07+4.42 [3.40, 5.72]5.09 [3.84, 6.33]10% [0%, 18%]19%38%-0.55+0.272026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC4.42 [3.27, 5.95]2.07+4.42 [3.27, 5.95]5.09 [3.76, 6.67]10% [0%, 17%]19%38%-0.55+0.272026-08-10 → 2026-08-30
tmin00Znearest365d27 1 QC5.64 [3.82, 8.75]3.51+5.37 [3.79, 8.32]7.25 [4.41, 10.88]7% [0%, 14%]19%33%-0.09+0.322026-01-10 → 2026-08-30
tmin00Znearestall27 1 QC5.64 [3.91, 8.98]3.51+5.37 [3.90, 8.13]7.25 [4.50, 11.14]7% [0%, 15%]19%33%-0.09+0.322026-01-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC4.28 [3.35, 5.16]2.02+4.23 [3.26, 5.16]4.86 [3.85, 5.57]5% [0%, 13%]19%38%-0.50+0.292026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC4.28 [3.25, 5.22]2.02+4.23 [3.16, 5.22]4.86 [3.42, 5.61]5% [0%, 14%]19%38%-0.50+0.292026-08-10 → 2026-08-30
tmin12Zbilinear365d26 1 QC4.55 [3.62, 5.83]2.65+4.14 [3.11, 5.33]5.36 [4.22, 6.80]4% [0%, 11%]19%35%+0.04+0.432026-01-10 → 2026-08-30
tmin12Zbilinearall26 1 QC4.55 [3.64, 5.72]2.65+4.14 [3.13, 5.17]5.36 [4.20, 6.88]4% [0%, 11%]19%35%+0.04+0.432026-01-10 → 2026-08-30
tmin12Znearest30d21 1 QC4.16 [3.23, 5.03]2.03+4.09 [3.11, 5.03]4.74 [3.73, 5.44]5% [0%, 13%]19%38%-0.45+0.292026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC4.16 [3.12, 5.10]2.03+4.09 [2.99, 5.10]4.74 [3.29, 5.48]5% [0%, 14%]19%38%-0.45+0.292026-08-10 → 2026-08-30
tmin12Znearest365d26 1 QC4.46 [3.51, 5.79]2.64+4.05 [3.04, 5.28]5.29 [4.06, 6.81]4% [0%, 11%]19%35%+0.06+0.432026-01-10 → 2026-08-30
tmin12Znearestall26 1 QC4.46 [3.52, 5.76]2.64+4.05 [3.04, 5.09]5.29 [4.08, 6.95]4% [0%, 11%]19%35%+0.06+0.432026-01-10 → 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 9, 00Z bilinear tmax+20+100-10-202026-08-10: -2.65 °F2026-08-11: -11.2 °F2026-08-12: -4.93 °F2026-08-13: -3.87 °F2026-08-14: -2.11 °F2026-08-15: -8.52 °F2026-08-16: -7.57 °F2026-08-17: -10.08 °F2026-08-18: -6.95 °F2026-08-19: -8.26 °F2026-08-20: -8.06 °F2026-08-21: -7.95 °F2026-08-22: -11.13 °F2026-08-23: -9.75 °F2026-08-24: -9.64 °F2026-08-25: -9.19 °F2026-08-26: -8.29 °F2026-08-27: -8.98 °F2026-08-28: -3.58 °F2026-08-29: -9.24 °F2026-08-30: -5.27 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-5.27
2026-08-29-9.24
2026-08-28-3.58
2026-08-27-8.98
2026-08-26-8.29
2026-08-25-9.19
2026-08-24-9.64
2026-08-23-9.75
2026-08-22-11.13
2026-08-21-7.95
2026-08-20-8.06
2026-08-19-8.26
2026-08-18-6.95
2026-08-17-10.08
2026-08-16-7.57
2026-08-15-8.52
2026-08-14-2.11
2026-08-13-3.87
2026-08-12-4.93
2026-08-11-11.20
2026-08-10-2.65

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KAUS, lead day 9-20 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: 4 days-10 to -8 °F: 9 days-8 to -6 °F: 3 days-6 to -4 °F: 2 days-4 to -2 °F: 4 days-2 to 0 °F: 0 days0 to 2 °F: 0 days2 to 4 °F: 2 days4 to 6 °F: 1 day6 to 8 °F: 0 days8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 1 day14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 8.26 · P90 |e| 11.16 °F-200+20 °Fn = 27 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
-12.00-10.004
-10.00-8.009
-8.00-6.003
-6.00-4.002
-4.00-2.004
-2.00+0.000
+0.00+2.000
+2.00+4.002
+4.00+6.001
+6.00+8.000
+8.00+10.000
+10.00+12.000
+12.00+14.001
+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
2026-08217.49 -7.49
2026-0167.80 -0.07

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 26
GraphCast (IFS init)2026-01-10 → 2026-08-30 26

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 21 +2.57 [1.37, 3.94] yes
NCEP GFS 21 +4.81 [3.60, 6.06] yes
ECMWF IFS HRES 16 +3.82 [0.01, 4.63] yes
Persistence (baseline) 21 +5.15 [3.70, 6.07] yes

Cite this page

ShortCastCheck, KAUS graphcast_ifs lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KAUS/model/graphcast_ifs/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KAUS (Austin Bergstrom), model graphcast_ifs, lead day 9. 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/9/

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