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

New York Central Park · GraphCast (GFS init) · lead day 0

KNYC · graphcast_gfs · lead 0

Target day = initialization date + 0 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 2026-08-28 — 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
tmax00Zbilinear30d2 1 QC0.97 [0.78, 1.16]0.19-0.97 [-1.16, -0.78]0.99 [0.78, 1.16]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Zbilinear90d2 1 QC0.97 [0.78, 1.16]0.19-0.97 [-1.16, -0.78]0.99 [0.78, 1.16]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Zbilinear365d2 1 QC0.97 [0.78, 1.16]0.19-0.97 [-1.16, -0.78]0.99 [0.78, 1.16]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Zbilinearall2 1 QC0.97 [0.78, 1.16]0.19-0.97 [-1.16, -0.78]0.99 [0.78, 1.16]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Znearest30d2 1 QC0.78 [0.62, 0.94]0.16-0.78 [-0.94, -0.62]0.80 [0.62, 0.94]100% [100%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Znearest90d2 1 QC0.78 [0.62, 0.94]0.16-0.78 [-0.94, -0.62]0.80 [0.62, 0.94]100% [100%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Znearest365d2 1 QC0.78 [0.62, 0.94]0.16-0.78 [-0.94, -0.62]0.80 [0.62, 0.94]100% [100%, 100%]100%100%——2026-08-29 → 2026-08-30
tmax00Znearestall2 1 QC0.78 [0.62, 0.94]0.16-0.78 [-0.94, -0.62]0.80 [0.62, 0.94]100% [100%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinear30d2 1 QC0.59 [0.14, 1.05]0.59+0.45 [-0.14, 1.05]0.75 [0.14, 1.05]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinear90d2 1 QC0.59 [0.14, 1.05]0.59+0.45 [-0.14, 1.05]0.75 [0.14, 1.05]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinear365d2 1 QC0.59 [0.14, 1.05]0.59+0.45 [-0.14, 1.05]0.75 [0.14, 1.05]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Zbilinearall2 1 QC0.59 [0.14, 1.05]0.59+0.45 [-0.14, 1.05]0.75 [0.14, 1.05]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearest30d2 1 QC0.74 [0.23, 1.26]0.51+0.74 [0.23, 1.26]0.90 [0.23, 1.26]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearest90d2 1 QC0.74 [0.23, 1.26]0.51+0.74 [0.23, 1.26]0.90 [0.23, 1.26]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearest365d2 1 QC0.74 [0.23, 1.26]0.51+0.74 [0.23, 1.26]0.90 [0.23, 1.26]50% [0%, 100%]100%100%——2026-08-29 → 2026-08-30
tmin00Znearestall2 1 QC0.74 [0.23, 1.26]0.51+0.74 [0.23, 1.26]0.90 [0.23, 1.26]50% [0%, 100%]100%100%——2026-08-29 → 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 (GFS init) at KNYC, lead day 0, 00Z bilinear tmax+2+10-1-22026-08-29: -0.78 °F2026-08-30: -1.16 °F2026-08-292026-08-30°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 (2 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.16
2026-08-29-0.78

Error distribution

Distribution of the signed daily error in °F for GraphCast (GFS init) at KNYC, lead day 0-2 to -1.8 °F: 0 days-1.8 to -1.6 °F: 0 days-1.6 to -1.4 °F: 0 days-1.4 to -1.2 °F: 0 days-1.2 to -1 °F: 1 day-1 to -0.8 °F: 0 days-0.8 to -0.6 °F: 1 day-0.6 to -0.4 °F: 0 days-0.4 to -0.2 °F: 0 days-0.2 to 0 °F: 0 days0 to 0.2 °F: 0 days0.2 to 0.4 °F: 0 days0.4 to 0.6 °F: 0 days0.6 to 0.8 °F: 0 days0.8 to 1 °F: 0 days1 to 1.2 °F: 0 days1.2 to 1.4 °F: 0 days1.4 to 1.6 °F: 0 days1.6 to 1.8 °F: 0 days1.8 to 2 °F: 0 daysdashed: P50 |e| 0.97 · P90 |e| 1.12 °F-20+2 °Fn = 2 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
-2.00-1.800
-1.80-1.600
-1.60-1.400
-1.40-1.200
-1.20-1.001
-1.00-0.800
-0.80-0.601
-0.60-0.400
-0.40-0.200
-0.20+0.000
+0.00+0.200
+0.20+0.400
+0.40+0.600
+0.60+0.800
+0.80+1.000
+1.00+1.200
+1.20+1.400
+1.40+1.600
+1.60+1.800
+1.80+2.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-0820.97 -0.97

Availability

ModelScored period DaysCoverage
GraphCast (GFS init)2026-08-29 → 2026-08-30 2
GraphCast (GFS init)2026-08-29 → 2026-08-30 2

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means GraphCast (GFS init) has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 2 -0.78 [-1.65, 0.08] no
Aurora (GFS init) 2 +0.02 [-0.30, 0.34] no
Aurora (IFS init) 2 -0.07 [-0.12, -0.02] yes
FourCastNet v2 (GFS init) 2 -0.72 [-1.44, 0.00] no
FourCastNet v2 (IFS init) 2 -0.26 [-0.93, 0.41] no
NCEP GFS 2 -4.70 [-4.97, -4.43] yes
GraphCast (IFS init) 2 -0.30 [-0.77, 0.16] no
ECMWF IFS HRES 2 -2.53 [-4.92, -0.14] yes
Pangu-Weather (GFS init) 2 -2.84 [-3.58, -2.09] yes
Pangu-Weather (IFS init) 2 -2.98 [-3.94, -2.01] yes

Cite this page

ShortCastCheck, KNYC graphcast_gfs lead 0, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KNYC/model/graphcast_gfs/lead/0/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KNYC (New York Central Park), model graphcast_gfs, lead day 0. 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_gfs/lead/0/

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