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

New York Central Park · GraphCast (IFS init) · lead day 6

KNYC · 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 QC2.38 [1.89, 2.87]2.08-1.38 [-1.93, -0.57]3.04 [2.48, 3.53]25% [6%, 46%]54%71%+0.35+0.392026-08-07 → 2026-08-30
tmax00Zbilinear90d24 1 QC2.38 [1.82, 2.90]2.08-1.38 [-1.94, -0.46]3.04 [2.35, 3.55]25% [0%, 47%]54%71%+0.35+0.392026-08-07 → 2026-08-30
tmax00Zbilinear365d30 1 QC3.07 [2.08, 4.67]2.79-1.06 [-2.04, 0.53]4.13 [2.70, 5.93]23% [5%, 45%]47%60%+0.46+0.542026-01-07 → 2026-08-30
tmax00Zbilinearall30 1 QC3.07 [2.09, 4.90]2.79-1.06 [-2.01, 0.63]4.13 [2.66, 6.10]23% [6%, 43%]47%60%+0.46+0.542026-01-07 → 2026-08-30
tmax00Znearest30d24 1 QC2.35 [1.88, 2.87]2.08-1.27 [-1.83, -0.46]2.99 [2.42, 3.51]25% [6%, 46%]58%71%+0.36+0.392026-08-07 → 2026-08-30
tmax00Znearest90d24 1 QC2.35 [1.79, 2.88]2.08-1.27 [-1.86, -0.34]2.99 [2.31, 3.52]25% [0%, 47%]58%71%+0.36+0.392026-08-07 → 2026-08-30
tmax00Znearest365d30 1 QC3.02 [2.05, 4.59]2.79-0.94 [-1.93, 0.65]4.09 [2.65, 5.91]23% [5%, 45%]50%60%+0.47+0.542026-01-07 → 2026-08-30
tmax00Znearestall30 1 QC3.02 [2.04, 4.78]2.79-0.94 [-1.89, 0.74]4.09 [2.61, 6.07]23% [6%, 43%]50%60%+0.47+0.542026-01-07 → 2026-08-30
tmax12Zbilinear30d24 1 QC2.13 [1.75, 2.62]1.83-1.17 [-1.98, -0.27]2.56 [2.16, 2.98]25% [10%, 38%]50%75%+0.42+0.462026-08-07 → 2026-08-30
tmax12Zbilinear90d24 1 QC2.13 [1.71, 2.86]1.83-1.17 [-2.00, -0.01]2.56 [2.10, 3.13]25% [0%, 38%]50%75%+0.42+0.462026-08-07 → 2026-08-30
tmax12Zbilinear365d29 1 QC2.50 [1.82, 3.70]2.30-0.74 [-1.82, 0.88]3.10 [2.24, 4.35]21% [0%, 34%]45%69%+0.57+0.632026-01-07 → 2026-08-30
tmax12Zbilinearall29 1 QC2.50 [1.82, 3.78]2.30-0.74 [-1.76, 0.90]3.10 [2.24, 4.44]21% [0%, 34%]45%69%+0.57+0.632026-01-07 → 2026-08-30
tmax12Znearest30d24 1 QC2.09 [1.73, 2.60]1.84-1.07 [-1.88, -0.17]2.52 [2.11, 2.96]25% [10%, 38%]46%75%+0.43+0.462026-08-07 → 2026-08-30
tmax12Znearest90d24 1 QC2.09 [1.67, 2.85]1.84-1.07 [-1.89, 0.08]2.52 [2.03, 3.11]25% [0%, 38%]46%75%+0.43+0.462026-08-07 → 2026-08-30
tmax12Znearest365d29 1 QC2.47 [1.79, 3.66]2.30-0.63 [-1.72, 1.00]3.09 [2.18, 4.39]21% [0%, 34%]45%69%+0.58+0.632026-01-07 → 2026-08-30
tmax12Znearestall29 1 QC2.47 [1.79, 3.78]2.30-0.63 [-1.66, 1.07]3.09 [2.19, 4.48]21% [0%, 34%]45%69%+0.58+0.632026-01-07 → 2026-08-30
tmin00Zbilinear30d24 1 QC2.38 [1.52, 3.37]2.39+1.44 [0.59, 2.46]3.24 [2.20, 4.19]46% [21%, 71%]58%67%+0.28+0.282026-08-07 → 2026-08-30
tmin00Zbilinear90d24 1 QC2.38 [1.45, 3.63]2.39+1.44 [0.49, 2.63]3.24 [2.05, 4.38]46% [18%, 75%]58%67%+0.28+0.282026-08-07 → 2026-08-30
tmin00Zbilinear365d30 1 QC3.19 [1.81, 5.22]3.17+1.31 [0.17, 2.46]4.32 [2.58, 6.16]37% [8%, 64%]47%57%+0.38+0.402026-01-07 → 2026-08-30
tmin00Zbilinearall30 1 QC3.19 [1.72, 5.33]3.17+1.31 [0.19, 2.61]4.32 [2.40, 6.30]37% [10%, 64%]47%57%+0.38+0.402026-01-07 → 2026-08-30
tmin00Znearest30d24 1 QC2.43 [1.55, 3.42]2.37+1.62 [0.78, 2.64]3.30 [2.24, 4.27]33% [13%, 56%]58%67%+0.26+0.292026-08-07 → 2026-08-30
tmin00Znearest90d24 1 QC2.43 [1.49, 3.69]2.37+1.62 [0.67, 2.78]3.30 [2.09, 4.42]33% [10%, 57%]58%67%+0.26+0.292026-08-07 → 2026-08-30
tmin00Znearest365d30 1 QC3.22 [1.86, 5.18]3.14+1.48 [0.36, 2.63]4.35 [2.62, 6.19]27% [3%, 50%]47%57%+0.37+0.412026-01-07 → 2026-08-30
tmin00Znearestall30 1 QC3.22 [1.77, 5.28]3.14+1.48 [0.36, 2.77]4.35 [2.44, 6.30]27% [6%, 50%]47%57%+0.37+0.412026-01-07 → 2026-08-30
tmin12Zbilinear30d24 1 QC2.83 [2.12, 3.75]2.72+1.33 [0.06, 2.75]3.57 [2.54, 4.66]21% [6%, 32%]46%62%+0.14+0.182026-08-07 → 2026-08-30
tmin12Zbilinear90d24 1 QC2.83 [2.08, 3.89]2.72+1.33 [0.04, 2.92]3.57 [2.48, 4.81]21% [0%, 31%]46%62%+0.14+0.182026-08-07 → 2026-08-30
tmin12Zbilinear365d29 1 QC3.49 [2.26, 5.32]3.44+1.25 [-0.16, 2.95]4.59 [2.67, 6.60]21% [8%, 30%]41%55%+0.33+0.362026-01-07 → 2026-08-30
tmin12Zbilinearall29 1 QC3.49 [2.22, 5.43]3.44+1.25 [-0.31, 3.02]4.59 [2.65, 6.69]21% [8%, 31%]41%55%+0.33+0.362026-01-07 → 2026-08-30
tmin12Znearest30d24 1 QC2.85 [2.13, 3.81]2.71+1.49 [0.23, 2.89]3.62 [2.55, 4.74]21% [6%, 32%]46%62%+0.13+0.192026-08-07 → 2026-08-30
tmin12Znearest90d24 1 QC2.85 [2.07, 3.94]2.71+1.49 [0.21, 3.04]3.62 [2.48, 4.88]21% [0%, 31%]46%62%+0.13+0.192026-08-07 → 2026-08-30
tmin12Znearest365d29 1 QC3.50 [2.26, 5.31]3.43+1.39 [-0.02, 3.06]4.61 [2.69, 6.62]21% [8%, 30%]41%55%+0.32+0.362026-01-07 → 2026-08-30
tmin12Znearestall29 1 QC3.50 [2.22, 5.39]3.43+1.39 [-0.17, 3.16]4.61 [2.68, 6.69]21% [8%, 31%]41%55%+0.32+0.362026-01-07 → 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 KNYC, lead day 6, 00Z bilinear tmax+10+50-5-102026-08-07: -2.45 °F2026-08-08: -1.21 °F2026-08-09: -0.4 °F2026-08-10: +0.1 °F2026-08-11: -6.29 °F2026-08-12: -0.85 °F2026-08-13: +0.41 °F2026-08-14: -5.02 °F2026-08-15: -1.5 °F2026-08-16: +0.72 °F2026-08-17: +3.69 °F2026-08-18: -5.4 °F2026-08-19: -1.55 °F2026-08-20: -1.18 °F2026-08-21: -1.74 °F2026-08-22: +1.2 °F2026-08-23: -3.8 °F2026-08-24: -2.64 °F2026-08-25: -2.01 °F2026-08-26: -2.5 °F2026-08-27: +0.02 °F2026-08-28: -6.52 °F2026-08-29: +4.14 °F2026-08-30: +1.74 °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+1.74
2026-08-29+4.14
2026-08-28-6.52
2026-08-27+0.02
2026-08-26-2.50
2026-08-25-2.01
2026-08-24-2.64
2026-08-23-3.80
2026-08-22+1.20
2026-08-21-1.74
2026-08-20-1.18
2026-08-19-1.55
2026-08-18-5.40
2026-08-17+3.69
2026-08-16+0.72
2026-08-15-1.50
2026-08-14-5.02
2026-08-13+0.41
2026-08-12-0.85
2026-08-11-6.29
2026-08-10+0.10
2026-08-09-0.40
2026-08-08-1.21
2026-08-07-2.45

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KNYC, 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: 0 days-12 to -10 °F: 0 days-10 to -8 °F: 1 day-8 to -6 °F: 2 days-6 to -4 °F: 2 days-4 to -2 °F: 7 days-2 to 0 °F: 8 days0 to 2 °F: 6 days2 to 4 °F: 1 day4 to 6 °F: 2 days6 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| 2.23 · P90 |e| 6.32 °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
-14.00-12.000
-12.00-10.000
-10.00-8.001
-8.00-6.002
-6.00-4.002
-4.00-2.007
-2.00+0.008
+0.00+2.006
+2.00+4.001
+4.00+6.002
+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
2026-08242.38 -1.38
2026-0165.81 +0.19

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 +0.10 [-0.82, 0.93] no
NCEP GFS 24 -2.07 [-4.37, -0.64] yes
ECMWF IFS HRES 19 -1.26 [-2.66, -0.02] yes
Persistence (baseline) 24 -1.29 [-2.41, -0.27] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KNYC (New York Central Park), 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/KNYC/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