Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

Austin Bergstrom · GraphCast (IFS init) · lead day 6

KAUS · graphcast_ifs · lead 6

Target day = initialization date + 6 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
tmax00Zbilinear30d24 1 QC7.17 [5.57, 8.63]1.95-7.17 [-8.63, -5.57]7.55 [5.69, 8.91]0% [0%, 0%]0%4%-2.31+0.082026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC7.17 [5.31, 8.73]1.95-7.17 [-8.73, -5.31]7.55 [5.38, 9.02]0% [0%, 0%]0%4%-2.31+0.082026-08-07 → 2026-08-30
tmax00Zbilinear365d30 1 QC7.50 [6.03, 9.23]2.48-7.50 [-9.23, -6.03]8.14 [6.43, 9.86]0% [0%, 0%]0%7%-0.94+0.412026-01-07 → 2026-08-30
tmax00Zbilinearall30 1 QC7.50 [6.07, 9.11]2.48-7.50 [-9.11, -6.07]8.14 [6.35, 9.83]0% [0%, 0%]0%7%-0.94+0.412026-01-07 → 2026-08-30
tmax00Znearest30d24 1 QC7.15 [5.55, 8.58]1.96-7.15 [-8.58, -5.55]7.53 [5.69, 8.87]0% [0%, 0%]0%4%-2.30+0.082026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC7.15 [5.27, 8.67]1.96-7.15 [-8.67, -5.27]7.53 [5.35, 8.99]0% [0%, 0%]0%4%-2.30+0.082026-08-07 → 2026-08-30
tmax00Znearest365d30 1 QC7.52 [6.02, 9.25]2.50-7.52 [-9.25, -6.02]8.17 [6.44, 9.95]0% [0%, 0%]0%7%-0.95+0.402026-01-07 → 2026-08-30
tmax00Znearestall30 1 QC7.52 [6.08, 9.20]2.50-7.52 [-9.20, -6.08]8.17 [6.40, 9.88]0% [0%, 0%]0%7%-0.95+0.402026-01-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC7.47 [6.05, 8.78]1.78-7.47 [-8.78, -6.05]7.79 [6.17, 9.07]0% [0%, 0%]0%0%-2.45+0.162026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC7.47 [5.89, 8.86]1.78-7.47 [-8.86, -5.89]7.79 [5.95, 9.16]0% [0%, 0%]0%0%-2.45+0.162026-08-07 → 2026-08-30
tmax12Zbilinear365d29 1 QC7.00 [5.22, 8.66]2.11-7.00 [-8.66, -5.22]7.51 [5.67, 8.96]3% [0%, 13%]3%7%-1.09+0.402026-01-07 → 2026-08-30
tmax12Zbilinearall29 1 QC7.00 [5.07, 8.49]2.11-7.00 [-8.49, -5.07]7.51 [5.77, 8.85]3% [0%, 15%]3%7%-1.09+0.402026-01-07 → 2026-08-30
tmax12Znearest30d24 1 QC7.45 [6.05, 8.75]1.78-7.45 [-8.75, -6.05]7.78 [6.18, 9.02]0% [0%, 0%]0%0%-2.44+0.162026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC7.45 [5.88, 8.81]1.78-7.45 [-8.81, -5.88]7.78 [5.96, 9.11]0% [0%, 0%]0%0%-2.44+0.162026-08-07 → 2026-08-30
tmax12Znearest365d29 1 QC6.99 [5.22, 8.62]2.13-6.99 [-8.62, -5.22]7.50 [5.71, 8.90]3% [0%, 13%]3%7%-1.09+0.402026-01-07 → 2026-08-30
tmax12Znearestall29 1 QC6.99 [5.09, 8.46]2.13-6.99 [-8.46, -5.09]7.50 [5.79, 8.80]3% [0%, 15%]3%7%-1.09+0.402026-01-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC4.96 [4.01, 6.08]1.69+4.96 [4.01, 6.08]5.38 [4.61, 6.27]4% [0%, 12%]8%17%-0.65+0.432026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC4.96 [4.01, 6.29]1.69+4.96 [4.01, 6.29]5.38 [4.57, 6.48]4% [0%, 12%]8%17%-0.65+0.432026-08-07 → 2026-08-30
tmin00Zbilinear365d30 1 QC4.83 [4.01, 5.90]1.81+4.83 [4.01, 5.90]5.35 [4.69, 6.17]7% [0%, 15%]13%20%-0.10+0.592026-01-07 → 2026-08-30
tmin00Zbilinearall30 1 QC4.83 [4.04, 5.84]1.81+4.83 [4.04, 5.84]5.35 [4.72, 6.15]7% [0%, 15%]13%20%-0.10+0.592026-01-07 → 2026-08-30
tmin00Znearest30d24 1 QC4.90 [3.92, 6.02]1.69+4.90 [3.92, 6.02]5.32 [4.53, 6.23]4% [0%, 12%]8%17%-0.63+0.432026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC4.90 [3.92, 6.25]1.69+4.90 [3.92, 6.25]5.32 [4.47, 6.42]4% [0%, 12%]8%17%-0.63+0.432026-08-07 → 2026-08-30
tmin00Znearest365d30 1 QC4.74 [3.87, 5.83]1.83+4.74 [3.86, 5.83]5.26 [4.58, 6.10]10% [0%, 25%]13%20%-0.08+0.592026-01-07 → 2026-08-30
tmin00Znearestall30 1 QC4.74 [3.91, 5.78]1.83+4.74 [3.90, 5.78]5.26 [4.62, 6.10]10% [0%, 25%]13%20%-0.08+0.592026-01-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC4.48 [3.58, 5.55]1.74+4.47 [3.56, 5.55]4.92 [4.16, 5.78]4% [0%, 12%]12%29%-0.49+0.412026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC4.48 [3.55, 5.86]1.74+4.47 [3.53, 5.86]4.92 [4.09, 6.04]4% [0%, 12%]12%29%-0.49+0.412026-08-07 → 2026-08-30
tmin12Zbilinear365d29 1 QC4.52 [3.71, 5.48]1.88+4.52 [3.69, 5.48]5.03 [4.29, 5.86]7% [0%, 17%]14%31%-0.09+0.552026-01-07 → 2026-08-30
tmin12Zbilinearall29 1 QC4.52 [3.64, 5.54]1.88+4.52 [3.62, 5.53]5.03 [4.27, 5.88]7% [0%, 17%]14%31%-0.09+0.552026-01-07 → 2026-08-30
tmin12Znearest30d24 1 QC4.40 [3.49, 5.48]1.74+4.38 [3.43, 5.48]4.84 [4.06, 5.70]4% [0%, 12%]12%29%-0.47+0.412026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC4.40 [3.46, 5.75]1.74+4.38 [3.40, 5.75]4.84 [4.01, 5.93]4% [0%, 12%]12%29%-0.47+0.412026-08-07 → 2026-08-30
tmin12Znearest365d29 1 QC4.42 [3.62, 5.36]1.86+4.40 [3.58, 5.35]4.91 [4.19, 5.73]7% [0%, 17%]14%31%-0.07+0.562026-01-07 → 2026-08-30
tmin12Znearestall29 1 QC4.42 [3.55, 5.42]1.86+4.40 [3.49, 5.42]4.91 [4.14, 5.74]7% [0%, 17%]14%31%-0.07+0.562026-01-07 → 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 6, 00Z bilinear tmax+20+100-10-202026-08-07: -4.87 °F2026-08-08: -6.06 °F2026-08-09: -5.67 °F2026-08-10: -4.44 °F2026-08-11: -4.64 °F2026-08-12: -4.97 °F2026-08-13: -6.35 °F2026-08-14: -2.97 °F2026-08-15: -9.86 °F2026-08-16: -8.24 °F2026-08-17: -10.09 °F2026-08-18: -8.29 °F2026-08-19: -7.09 °F2026-08-20: -8.39 °F2026-08-21: -8.54 °F2026-08-22: -12.75 °F2026-08-23: -11.27 °F2026-08-24: -9.58 °F2026-08-25: -7.83 °F2026-08-26: -4.22 °F2026-08-27: -6.72 °F2026-08-28: -7.52 °F2026-08-29: -5.77 °F2026-08-30: -6.02 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-6.02
2026-08-29-5.77
2026-08-28-7.52
2026-08-27-6.72
2026-08-26-4.22
2026-08-25-7.83
2026-08-24-9.58
2026-08-23-11.27
2026-08-22-12.75
2026-08-21-8.54
2026-08-20-8.39
2026-08-19-7.09
2026-08-18-8.29
2026-08-17-10.09
2026-08-16-8.24
2026-08-15-9.86
2026-08-14-2.97
2026-08-13-6.35
2026-08-12-4.97
2026-08-11-4.64
2026-08-10-4.44
2026-08-09-5.67
2026-08-08-6.06
2026-08-07-4.87

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KAUS, lead day 6-20 to -18 °F: 0 days-18 to -16 °F: 1 day-16 to -14 °F: 0 days-14 to -12 °F: 2 days-12 to -10 °F: 3 days-10 to -8 °F: 6 days-8 to -6 °F: 8 days-6 to -4 °F: 7 days-4 to -2 °F: 3 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| 7.15 · P90 |e| 11.42 °F-200+20 °Fn = 30 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
-18.00-16.001
-16.00-14.000
-14.00-12.002
-12.00-10.003
-10.00-8.006
-8.00-6.008
-6.00-4.007
-4.00-2.003
-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
2026-08247.17 -7.17
2026-0168.82 -8.82

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 29
GraphCast (IFS init)2026-01-07 → 2026-08-30 29

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 24 +2.43 [-0.52, 3.85] no
NCEP GFS 24 +4.35 [1.35, 6.73] yes
ECMWF IFS HRES 19 +3.57 [1.10, 4.77] yes
Persistence (baseline) 24 +5.01 [2.80, 6.56] yes

Cite this page

ShortCastCheck, KAUS graphcast_ifs lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KAUS/model/graphcast_ifs/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KAUS (Austin Bergstrom), model graphcast_ifs, lead day 6. 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/6/

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