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

New York Central Park · GraphCast (IFS init) · lead day 9

KNYC · graphcast_ifs · lead 9

Target day = initialization date + 9 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
tmax00Zbilinear30d21 1 QC4.36 [3.11, 5.36]4.24-0.53 [-3.33, 2.27]5.04 [3.54, 6.18]0% [0%, 0%]14%29%-0.21-0.302026-08-10 → 2026-08-30
tmax00Zbilinear90d21 1 QC4.36 [2.76, 5.46]4.24-0.53 [-3.43, 2.56]5.04 [3.17, 6.18]0% [0%, 0%]14%29%-0.21-0.302026-08-10 → 2026-08-30
tmax00Zbilinear365d27 1 QC5.07 [3.52, 6.98]4.52-1.87 [-5.61, 1.33]5.92 [3.91, 7.91]0% [0%, 0%]11%26%+0.09+0.212026-01-10 → 2026-08-30
tmax00Zbilinearall27 1 QC5.07 [3.49, 6.88]4.52-1.87 [-5.90, 1.57]5.92 [3.93, 7.84]0% [0%, 0%]11%26%+0.09+0.212026-01-10 → 2026-08-30
tmax00Znearest30d21 1 QC4.31 [3.06, 5.35]4.22-0.40 [-3.19, 2.38]5.02 [3.50, 6.17]0% [0%, 0%]19%29%-0.19-0.292026-08-10 → 2026-08-30
tmax00Znearest90d21 1 QC4.31 [2.72, 5.38]4.22-0.40 [-3.30, 2.67]5.02 [3.12, 6.17]0% [0%, 0%]19%29%-0.19-0.292026-08-10 → 2026-08-30
tmax00Znearest365d27 1 QC5.01 [3.44, 6.87]4.50-1.75 [-5.47, 1.45]5.87 [3.85, 7.81]0% [0%, 0%]15%26%+0.10+0.222026-01-10 → 2026-08-30
tmax00Znearestall27 1 QC5.01 [3.44, 6.79]4.50-1.75 [-5.75, 1.69]5.87 [3.87, 7.73]0% [0%, 0%]15%26%+0.10+0.222026-01-10 → 2026-08-30
tmax12Zbilinear30d21 1 QC3.87 [3.09, 4.83]3.32-2.53 [-3.95, -1.19]4.65 [3.88, 5.34]14% [0%, 25%]29%38%-0.07-0.022026-08-10 → 2026-08-30
tmax12Zbilinear90d21 1 QC3.87 [2.95, 4.98]3.32-2.53 [-4.13, -0.62]4.65 [3.67, 5.46]14% [0%, 26%]29%38%-0.07-0.022026-08-10 → 2026-08-30
tmax12Zbilinear365d26 1 QC4.47 [3.34, 6.35]3.92-2.70 [-4.52, -1.07]5.38 [4.15, 7.15]12% [0%, 22%]23%31%+0.20+0.322026-01-10 → 2026-08-30
tmax12Zbilinearall26 1 QC4.47 [3.37, 6.52]3.92-2.70 [-4.59, -1.14]5.38 [4.25, 7.19]12% [0%, 22%]23%31%+0.20+0.322026-01-10 → 2026-08-30
tmax12Znearest30d21 1 QC3.80 [3.03, 4.72]3.30-2.41 [-3.82, -1.08]4.57 [3.82, 5.24]14% [0%, 25%]29%43%-0.05-0.012026-08-10 → 2026-08-30
tmax12Znearest90d21 1 QC3.80 [2.92, 4.89]3.30-2.41 [-4.05, -0.51]4.57 [3.65, 5.36]14% [0%, 26%]29%43%-0.05-0.012026-08-10 → 2026-08-30
tmax12Znearest365d26 1 QC4.40 [3.30, 6.27]3.89-2.57 [-4.38, -0.94]5.30 [4.10, 7.04]12% [0%, 22%]23%35%+0.22+0.322026-01-10 → 2026-08-30
tmax12Znearestall26 1 QC4.40 [3.30, 6.46]3.89-2.57 [-4.46, -1.05]5.30 [4.18, 7.09]12% [0%, 22%]23%35%+0.22+0.322026-01-10 → 2026-08-30
tmin00Zbilinear30d21 1 QC3.32 [2.02, 4.85]3.43+1.06 [-1.00, 3.19]4.58 [2.94, 6.13]29% [11%, 45%]48%52%+0.05-0.352026-08-10 → 2026-08-30
tmin00Zbilinear90d21 1 QC3.32 [1.95, 5.03]3.43+1.06 [-1.30, 3.51]4.58 [2.90, 6.24]29% [7%, 46%]48%52%+0.05-0.352026-08-10 → 2026-08-30
tmin00Zbilinear365d27 1 QC3.59 [2.23, 5.24]3.59-0.10 [-3.28, 2.49]5.03 [3.15, 6.61]30% [12%, 47%]44%52%+0.34+0.342026-01-10 → 2026-08-30
tmin00Zbilinearall27 1 QC3.59 [2.14, 5.17]3.59-0.10 [-3.46, 2.63]5.03 [3.05, 6.60]30% [11%, 47%]44%52%+0.34+0.342026-01-10 → 2026-08-30
tmin00Znearest30d21 1 QC3.31 [2.00, 4.86]3.38+1.21 [-0.82, 3.31]4.57 [2.92, 6.17]29% [7%, 52%]48%52%+0.05-0.332026-08-10 → 2026-08-30
tmin00Znearest90d21 1 QC3.31 [1.92, 5.00]3.38+1.21 [-1.12, 3.63]4.57 [2.82, 6.26]29% [0%, 56%]48%52%+0.05-0.332026-08-10 → 2026-08-30
tmin00Znearest365d27 1 QC3.56 [2.19, 5.14]3.56+0.05 [-3.10, 2.62]5.00 [3.07, 6.59]30% [8%, 50%]44%56%+0.35+0.352026-01-10 → 2026-08-30
tmin00Znearestall27 1 QC3.56 [2.10, 5.13]3.56+0.05 [-3.30, 2.76]5.00 [3.00, 6.60]30% [9%, 50%]44%56%+0.35+0.352026-01-10 → 2026-08-30
tmin12Zbilinear30d21 1 QC3.57 [2.35, 4.83]3.57-0.03 [-2.63, 2.23]4.48 [2.77, 5.72]19% [7%, 29%]33%57%-0.03-0.412026-08-10 → 2026-08-30
tmin12Zbilinear90d21 1 QC3.57 [2.26, 4.86]3.57-0.03 [-3.44, 2.69]4.48 [2.67, 5.79]19% [5%, 29%]33%57%-0.03-0.412026-08-10 → 2026-08-30
tmin12Zbilinear365d26 1 QC4.17 [2.81, 6.03]4.20-0.36 [-3.11, 2.06]5.11 [3.48, 6.67]15% [0%, 26%]27%46%+0.21+0.222026-01-10 → 2026-08-30
tmin12Zbilinearall26 1 QC4.17 [2.86, 6.26]4.20-0.36 [-3.34, 1.95]5.11 [3.62, 6.81]15% [0%, 25%]27%46%+0.21+0.222026-01-10 → 2026-08-30
tmin12Znearest30d21 1 QC3.57 [2.31, 4.86]3.55+0.13 [-2.47, 2.38]4.46 [2.73, 5.76]19% [4%, 38%]33%52%-0.03-0.402026-08-10 → 2026-08-30
tmin12Znearest90d21 1 QC3.57 [2.23, 4.86]3.55+0.13 [-3.28, 2.84]4.46 [2.65, 5.76]19% [0%, 38%]33%52%-0.03-0.402026-08-10 → 2026-08-30
tmin12Znearest365d26 1 QC4.16 [2.77, 5.96]4.18-0.21 [-2.97, 2.21]5.08 [3.41, 6.64]15% [0%, 33%]27%42%+0.21+0.232026-01-10 → 2026-08-30
tmin12Znearestall26 1 QC4.16 [2.83, 6.20]4.18-0.21 [-3.20, 2.10]5.08 [3.55, 6.75]15% [0%, 32%]27%42%+0.21+0.232026-01-10 → 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 9, 00Z bilinear tmax+20+100-10-202026-08-10: +2.22 °F2026-08-11: -1.48 °F2026-08-12: +2.18 °F2026-08-13: -6.79 °F2026-08-14: -3.48 °F2026-08-15: -4.63 °F2026-08-16: -4.16 °F2026-08-17: -5.95 °F2026-08-18: -6.36 °F2026-08-19: -3.36 °F2026-08-20: +3.96 °F2026-08-21: +8.92 °F2026-08-22: +11.45 °F2026-08-23: +1.09 °F2026-08-24: +4.2 °F2026-08-25: -2.12 °F2026-08-26: -3.34 °F2026-08-27: +6.24 °F2026-08-28: -5.05 °F2026-08-29: -1.29 °F2026-08-30: -3.39 °F2026-08-102026-08-30°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 (21 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.39
2026-08-29-1.29
2026-08-28-5.05
2026-08-27+6.24
2026-08-26-3.34
2026-08-25-2.12
2026-08-24+4.20
2026-08-23+1.09
2026-08-22+11.45
2026-08-21+8.92
2026-08-20+3.96
2026-08-19-3.36
2026-08-18-6.36
2026-08-17-5.95
2026-08-16-4.16
2026-08-15-4.63
2026-08-14-3.48
2026-08-13-6.79
2026-08-12+2.18
2026-08-11-1.48
2026-08-10+2.22

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KNYC, lead day 9-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 0 days-10 to -8 °F: 1 day-8 to -6 °F: 3 days-6 to -4 °F: 6 days-4 to -2 °F: 5 days-2 to 0 °F: 2 days0 to 2 °F: 1 day2 to 4 °F: 4 days4 to 6 °F: 1 day6 to 8 °F: 1 day8 to 10 °F: 1 day10 to 12 °F: 1 day12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 4.2 · P90 |e| 8.99 °F-200+20 °Fn = 27 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
-14.00-12.001
-12.00-10.000
-10.00-8.001
-8.00-6.003
-6.00-4.006
-4.00-2.005
-2.00+0.002
+0.00+2.001
+2.00+4.004
+4.00+6.001
+6.00+8.001
+8.00+10.001
+10.00+12.001
+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
2026-08214.36 -0.53
2026-0167.54 -6.58

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 27
GraphCast (IFS init)2026-01-10 → 2026-08-30 26
GraphCast (IFS init)2026-01-10 → 2026-08-30 26

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 21 -0.08 [-1.49, 1.46] no
NCEP GFS 21 -0.84 [-4.60, 1.71] no
ECMWF IFS HRES 16 +0.28 [-1.05, 1.25] no
Persistence (baseline) 21 +0.75 [-0.39, 1.67] no

Cite this page

ShortCastCheck, KNYC graphcast_ifs lead 9, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KNYC/model/graphcast_ifs/lead/9/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KNYC (New York Central Park), model graphcast_ifs, lead day 9. 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/9/

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