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

New York Central Park · GraphCast (IFS init) · lead day 8

KNYC · 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 QC3.52 [2.55, 4.28]3.44-0.80 [-2.35, 0.65]4.15 [3.00, 4.95]14% [0%, 35%]18%50%-0.03-0.042026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC3.52 [2.27, 4.45]3.44-0.80 [-2.74, 0.75]4.15 [2.63, 5.05]14% [0%, 38%]18%50%-0.03-0.042026-08-09 → 2026-08-30
tmax00Zbilinear365d28 1 QC3.74 [2.80, 4.57]3.43-1.42 [-3.33, 0.20]4.33 [3.41, 5.05]11% [0%, 31%]14%46%+0.33+0.412026-01-09 → 2026-08-30
tmax00Zbilinearall28 1 QC3.74 [2.81, 4.52]3.43-1.42 [-3.50, 0.22]4.33 [3.33, 5.07]11% [0%, 29%]14%46%+0.33+0.412026-01-09 → 2026-08-30
tmax00Znearest30d22 1 QC3.49 [2.54, 4.26]3.43-0.69 [-2.26, 0.74]4.13 [2.93, 4.95]14% [0%, 35%]18%50%-0.02-0.032026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC3.49 [2.28, 4.43]3.43-0.69 [-2.65, 0.85]4.13 [2.58, 5.05]14% [0%, 38%]18%50%-0.02-0.032026-08-09 → 2026-08-30
tmax00Znearest365d28 1 QC3.70 [2.78, 4.54]3.42-1.31 [-3.25, 0.30]4.29 [3.34, 5.01]11% [0%, 31%]14%46%+0.34+0.412026-01-09 → 2026-08-30
tmax00Znearestall28 1 QC3.70 [2.79, 4.46]3.42-1.31 [-3.40, 0.33]4.29 [3.28, 5.00]11% [0%, 29%]14%46%+0.34+0.412026-01-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC3.85 [3.34, 4.34]3.05-2.52 [-3.64, -1.48]4.48 [3.84, 4.98]14% [4%, 24%]18%27%-0.13+0.082026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC3.85 [3.30, 4.35]3.05-2.52 [-3.70, -1.34]4.48 [3.80, 4.96]14% [5%, 25%]18%27%-0.13+0.082026-08-09 → 2026-08-30
tmax12Zbilinear365d27 1 QC3.55 [2.73, 4.10]2.92-2.14 [-3.28, -0.67]4.20 [3.22, 4.83]15% [6%, 25%]22%37%+0.35+0.482026-01-09 → 2026-08-30
tmax12Zbilinearall27 1 QC3.55 [2.56, 4.14]2.92-2.14 [-3.32, -0.71]4.20 [2.98, 4.79]15% [6%, 25%]22%37%+0.35+0.482026-01-09 → 2026-08-30
tmax12Znearest30d22 1 QC3.78 [3.26, 4.27]3.05-2.40 [-3.53, -1.36]4.40 [3.77, 4.92]18% [9%, 29%]23%32%-0.11+0.082026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC3.78 [3.26, 4.27]3.05-2.40 [-3.59, -1.22]4.40 [3.74, 4.88]18% [7%, 31%]23%32%-0.11+0.082026-08-09 → 2026-08-30
tmax12Znearest365d27 1 QC3.48 [2.68, 4.04]2.92-2.01 [-3.17, -0.55]4.13 [3.18, 4.74]19% [8%, 31%]26%41%+0.36+0.482026-01-09 → 2026-08-30
tmax12Znearestall27 1 QC3.48 [2.50, 4.06]2.92-2.01 [-3.20, -0.59]4.13 [2.95, 4.70]19% [8%, 29%]26%41%+0.36+0.482026-01-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC3.47 [2.29, 4.83]3.40+0.79 [-0.95, 2.22]4.24 [2.79, 5.43]23% [6%, 41%]36%45%-0.02-0.082026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC3.47 [2.22, 4.96]3.40+0.79 [-1.32, 2.32]4.24 [2.61, 5.60]23% [0%, 43%]36%45%-0.02-0.082026-08-09 → 2026-08-30
tmin00Zbilinear365d28 1 QC3.90 [2.70, 5.38]3.90-0.01 [-2.30, 1.77]4.69 [3.35, 5.91]18% [0%, 36%]29%39%+0.24+0.262026-01-09 → 2026-08-30
tmin00Zbilinearall28 1 QC3.90 [2.68, 5.21]3.90-0.01 [-2.58, 1.77]4.69 [3.37, 5.81]18% [0%, 36%]29%39%+0.24+0.262026-01-09 → 2026-08-30
tmin00Znearest30d22 1 QC3.46 [2.29, 4.83]3.37+0.94 [-0.78, 2.37]4.25 [2.78, 5.44]23% [6%, 41%]36%45%-0.01-0.082026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC3.46 [2.24, 4.96]3.37+0.94 [-1.15, 2.46]4.25 [2.64, 5.63]23% [0%, 43%]36%45%-0.01-0.082026-08-09 → 2026-08-30
tmin00Znearest365d28 1 QC3.87 [2.66, 5.32]3.87+0.14 [-2.14, 1.90]4.67 [3.33, 5.86]18% [0%, 36%]29%39%+0.24+0.272026-01-09 → 2026-08-30
tmin00Znearestall28 1 QC3.87 [2.67, 5.16]3.87+0.14 [-2.44, 1.91]4.67 [3.32, 5.76]18% [0%, 36%]29%39%+0.24+0.272026-01-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC2.65 [1.94, 3.48]2.32+1.13 [-0.30, 2.21]3.28 [2.28, 4.14]18% [7%, 29%]45%64%+0.22+0.262026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC2.65 [1.94, 3.52]2.32+1.13 [-0.53, 2.34]3.28 [2.28, 4.21]18% [0%, 27%]45%64%+0.22+0.262026-08-09 → 2026-08-30
tmin12Zbilinear365d27 1 QC2.70 [2.02, 3.44]2.46+1.23 [-0.11, 2.36]3.42 [2.43, 4.26]22% [11%, 33%]44%63%+0.45+0.512026-01-09 → 2026-08-30
tmin12Zbilinearall27 1 QC2.70 [1.95, 3.47]2.46+1.23 [-0.20, 2.20]3.42 [2.35, 4.28]22% [12%, 33%]44%63%+0.45+0.512026-01-09 → 2026-08-30
tmin12Znearest30d22 1 QC2.70 [1.99, 3.52]2.32+1.28 [-0.15, 2.37]3.32 [2.37, 4.19]18% [7%, 29%]36%64%+0.21+0.262026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC2.70 [2.01, 3.57]2.32+1.28 [-0.38, 2.49]3.32 [2.35, 4.26]18% [0%, 27%]36%64%+0.21+0.262026-08-09 → 2026-08-30
tmin12Znearest365d27 1 QC2.75 [2.06, 3.46]2.46+1.38 [0.02, 2.49]3.46 [2.49, 4.31]22% [11%, 33%]37%63%+0.44+0.512026-01-09 → 2026-08-30
tmin12Znearestall27 1 QC2.75 [2.02, 3.50]2.46+1.38 [-0.10, 2.34]3.46 [2.40, 4.32]22% [12%, 33%]37%63%+0.44+0.512026-01-09 → 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 KNYC, lead day 8, 00Z bilinear tmax+10+50-5-102026-08-09: -2.42 °F2026-08-10: +0.65 °F2026-08-11: +2.82 °F2026-08-12: -4.28 °F2026-08-13: +0.65 °F2026-08-14: +0.79 °F2026-08-15: -4.8 °F2026-08-16: -2.21 °F2026-08-17: +3.72 °F2026-08-18: -7.04 °F2026-08-19: -3.77 °F2026-08-20: +3.9 °F2026-08-21: +2.67 °F2026-08-22: +8.09 °F2026-08-23: +3 °F2026-08-24: -2.43 °F2026-08-25: -4.13 °F2026-08-26: -1.56 °F2026-08-27: +3.59 °F2026-08-28: -9.54 °F2026-08-29: -2.44 °F2026-08-30: -2.86 °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
2026-08-30-2.86
2026-08-29-2.44
2026-08-28-9.54
2026-08-27+3.59
2026-08-26-1.56
2026-08-25-4.13
2026-08-24-2.43
2026-08-23+3.00
2026-08-22+8.09
2026-08-21+2.67
2026-08-20+3.90
2026-08-19-3.77
2026-08-18-7.04
2026-08-17+3.72
2026-08-16-2.21
2026-08-15-4.80
2026-08-14+0.79
2026-08-13+0.65
2026-08-12-4.28
2026-08-11+2.82
2026-08-10+0.65
2026-08-09-2.42

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KNYC, lead day 8-10 to -9 °F: 1 day-9 to -8 °F: 0 days-8 to -7 °F: 2 days-7 to -6 °F: 1 day-6 to -5 °F: 1 day-5 to -4 °F: 3 days-4 to -3 °F: 2 days-3 to -2 °F: 6 days-2 to -1 °F: 1 day-1 to 0 °F: 0 days0 to 1 °F: 3 days1 to 2 °F: 0 days2 to 3 °F: 3 days3 to 4 °F: 4 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 1 day9 to 10 °F: 0 daysdashed: P50 |e| 3.29 · P90 |e| 7.04 °F-100+10 °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
-10.00-9.001
-9.00-8.000
-8.00-7.002
-7.00-6.001
-6.00-5.001
-5.00-4.003
-4.00-3.002
-3.00-2.006
-2.00-1.001
-1.00+0.000
+0.00+1.003
+1.00+2.000
+2.00+3.003
+3.00+4.004
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.001
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08223.52 -0.80
2026-0164.56 -3.70

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 +1.18 [-0.09, 2.45] no
NCEP GFS 22 -0.15 [-2.51, 1.18] no
ECMWF IFS HRES 17 +0.58 [-0.90, 1.70] no
Persistence (baseline) 22 +0.11 [-1.06, 1.42] no

Cite this page

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

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