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

Minneapolis-St Paul · GraphCast (IFS init) · lead day 6

KMSP · 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 QC6.93 [5.79, 7.74]2.90-6.77 [-7.65, -5.27]7.69 [6.56, 8.48]0% [0%, 0%]12%17%-1.00+0.162026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC6.93 [5.60, 7.79]2.90-6.77 [-7.77, -4.98]7.69 [6.45, 8.61]0% [0%, 0%]12%17%-1.00+0.162026-08-07 → 2026-08-30
tmax00Zbilinear365d30 1 QC6.44 [4.96, 7.44]3.13-6.30 [-7.39, -4.61]7.36 [6.03, 8.24]3% [0%, 13%]20%23%-0.18+0.452026-01-07 → 2026-08-30
tmax00Zbilinearall30 1 QC6.44 [4.72, 7.48]3.13-6.30 [-7.42, -4.43]7.36 [5.85, 8.25]3% [0%, 13%]20%23%-0.18+0.452026-01-07 → 2026-08-30
tmax00Znearest30d24 1 QC6.96 [5.84, 7.77]2.86-6.80 [-7.69, -5.30]7.71 [6.58, 8.49]0% [0%, 0%]12%17%-1.01+0.172026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC6.96 [5.66, 7.83]2.86-6.80 [-7.80, -5.01]7.71 [6.47, 8.60]0% [0%, 0%]12%17%-1.01+0.172026-08-07 → 2026-08-30
tmax00Znearest365d30 1 QC6.48 [5.00, 7.48]3.13-6.34 [-7.44, -4.64]7.40 [6.08, 8.26]3% [0%, 13%]20%23%-0.19+0.452026-01-07 → 2026-08-30
tmax00Znearestall30 1 QC6.48 [4.75, 7.52]3.13-6.34 [-7.48, -4.47]7.40 [5.97, 8.27]3% [0%, 13%]20%23%-0.19+0.452026-01-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC6.70 [5.48, 7.54]3.14-6.31 [-7.47, -4.40]7.40 [6.41, 8.04]4% [0%, 11%]12%17%-0.94+0.092026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC6.70 [5.23, 7.57]3.14-6.31 [-7.50, -3.93]7.40 [6.24, 8.07]4% [0%, 12%]12%17%-0.94+0.092026-08-07 → 2026-08-30
tmax12Zbilinear365d29 1 QC6.08 [4.27, 7.23]3.13-5.77 [-7.16, -3.60]6.88 [5.00, 7.81]7% [0%, 17%]14%17%-0.15+0.432026-01-07 → 2026-08-30
tmax12Zbilinearall29 1 QC6.08 [3.75, 7.21]3.13-5.77 [-7.08, -3.38]6.88 [4.29, 7.81]7% [0%, 17%]14%17%-0.15+0.432026-01-07 → 2026-08-30
tmax12Znearest30d24 1 QC6.67 [5.45, 7.51]3.14-6.32 [-7.45, -4.43]7.39 [6.41, 8.00]4% [0%, 11%]17%17%-0.93+0.092026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC6.67 [5.22, 7.53]3.14-6.32 [-7.49, -4.02]7.39 [6.24, 8.04]4% [0%, 12%]17%17%-0.93+0.092026-08-07 → 2026-08-30
tmax12Znearest365d29 1 QC6.08 [4.29, 7.21]3.10-5.79 [-7.14, -3.69]6.88 [5.04, 7.78]7% [0%, 17%]17%17%-0.15+0.442026-01-07 → 2026-08-30
tmax12Znearestall29 1 QC6.08 [3.85, 7.18]3.10-5.79 [-7.05, -3.52]6.88 [4.36, 7.80]7% [0%, 17%]17%17%-0.15+0.442026-01-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC3.62 [2.05, 5.15]3.44-1.39 [-3.27, 0.68]4.55 [2.61, 5.98]25% [12%, 44%]33%46%+0.38+0.422026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC3.62 [1.79, 5.28]3.44-1.39 [-3.46, 0.74]4.55 [2.20, 6.12]25% [11%, 47%]33%46%+0.38+0.422026-08-07 → 2026-08-30
tmin00Zbilinear365d30 1 QC3.96 [2.36, 5.49]3.80-1.52 [-3.45, 0.63]4.87 [2.89, 6.24]20% [6%, 36%]27%40%+0.43+0.462026-01-07 → 2026-08-30
tmin00Zbilinearall30 1 QC3.96 [2.32, 5.45]3.80-1.52 [-3.40, 0.56]4.87 [2.87, 6.18]20% [6%, 37%]27%40%+0.43+0.462026-01-07 → 2026-08-30
tmin00Znearest30d24 1 QC3.64 [2.06, 5.21]3.44-1.49 [-3.39, 0.58]4.55 [2.60, 6.00]25% [12%, 44%]33%50%+0.38+0.422026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC3.64 [1.81, 5.38]3.44-1.49 [-3.58, 0.63]4.55 [2.25, 6.11]25% [11%, 47%]33%50%+0.38+0.422026-08-07 → 2026-08-30
tmin00Znearest365d30 1 QC4.01 [2.39, 5.60]3.84-1.63 [-3.61, 0.56]4.93 [2.83, 6.36]20% [6%, 36%]27%43%+0.42+0.462026-01-07 → 2026-08-30
tmin00Znearestall30 1 QC4.01 [2.33, 5.52]3.84-1.63 [-3.50, 0.49]4.93 [2.91, 6.29]20% [6%, 37%]27%43%+0.42+0.462026-01-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC3.28 [2.43, 4.19]2.96-1.39 [-2.69, 0.19]4.05 [2.90, 5.09]25% [14%, 37%]25%46%+0.44+0.502026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC3.28 [2.35, 4.36]2.96-1.39 [-2.87, 0.49]4.05 [2.77, 5.31]25% [12%, 38%]25%46%+0.44+0.502026-08-07 → 2026-08-30
tmin12Zbilinear365d29 1 QC3.39 [2.57, 4.29]3.29-0.83 [-2.31, 1.22]4.08 [3.05, 5.06]21% [7%, 32%]24%41%+0.52+0.542026-01-07 → 2026-08-30
tmin12Zbilinearall29 1 QC3.39 [2.58, 4.27]3.29-0.83 [-2.36, 1.34]4.08 [3.07, 5.04]21% [6%, 33%]24%41%+0.52+0.542026-01-07 → 2026-08-30
tmin12Znearest30d24 1 QC3.36 [2.45, 4.29]2.98-1.53 [-2.87, 0.06]4.11 [2.90, 5.16]25% [14%, 37%]25%46%+0.43+0.502026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC3.36 [2.36, 4.47]2.98-1.53 [-3.02, 0.35]4.11 [2.77, 5.38]25% [12%, 38%]25%46%+0.43+0.502026-08-07 → 2026-08-30
tmin12Znearest365d29 1 QC3.44 [2.58, 4.41]3.31-0.98 [-2.48, 1.04]4.13 [3.04, 5.15]24% [13%, 36%]24%41%+0.51+0.542026-01-07 → 2026-08-30
tmin12Znearestall29 1 QC3.44 [2.57, 4.38]3.31-0.98 [-2.51, 1.18]4.13 [3.05, 5.11]24% [12%, 36%]24%41%+0.51+0.542026-01-07 → 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 KMSP, lead day 6, 00Z bilinear tmax+20+100-10-202026-08-07: +1.88 °F2026-08-08: -2.26 °F2026-08-09: -7.04 °F2026-08-10: -12.58 °F2026-08-11: -11.07 °F2026-08-12: -8.79 °F2026-08-13: -4.57 °F2026-08-14: -10.23 °F2026-08-15: -1.32 °F2026-08-16: -10.52 °F2026-08-17: -6.22 °F2026-08-18: -7.32 °F2026-08-19: -6.96 °F2026-08-20: -5.38 °F2026-08-21: -4.6 °F2026-08-22: -5.59 °F2026-08-23: -8.31 °F2026-08-24: -10.88 °F2026-08-25: -1.14 °F2026-08-26: -7.62 °F2026-08-27: -12.75 °F2026-08-28: -6.84 °F2026-08-29: -8.61 °F2026-08-30: -3.71 °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
2026-08-30-3.71
2026-08-29-8.61
2026-08-28-6.84
2026-08-27-12.75
2026-08-26-7.62
2026-08-25-1.14
2026-08-24-10.88
2026-08-23-8.31
2026-08-22-5.59
2026-08-21-4.60
2026-08-20-5.38
2026-08-19-6.96
2026-08-18-7.32
2026-08-17-6.22
2026-08-16-10.52
2026-08-15-1.32
2026-08-14-10.23
2026-08-13-4.57
2026-08-12-8.79
2026-08-11-11.07
2026-08-10-12.58
2026-08-09-7.04
2026-08-08-2.26
2026-08-07+1.88

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KMSP, lead day 6-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 2 days-12 to -10 °F: 4 days-10 to -8 °F: 5 days-8 to -6 °F: 7 days-6 to -4 °F: 4 days-4 to -2 °F: 2 days-2 to 0 °F: 4 days0 to 2 °F: 2 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| 6.9 · P90 |e| 10.9 °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
-18.00-16.000
-16.00-14.000
-14.00-12.002
-12.00-10.004
-10.00-8.005
-8.00-6.007
-6.00-4.004
-4.00-2.002
-2.00+0.004
+0.00+2.002
+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
2026-08246.93 -6.77
2026-0164.49 -4.41

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 +1.08 [-0.26, 2.14] no
NCEP GFS 24 +2.17 [-0.58, 4.32] no
ECMWF IFS HRES 19 +1.61 [-1.76, 2.55] no
Persistence (baseline) 24 +3.47 [1.40, 4.93] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KMSP (Minneapolis-St Paul), 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/KMSP/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