Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

New York Central Park · NCEP GFS · lead day 4

KNYC · gfs · lead 4

Target day = initialization date + 4 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, gfs-0p25, starting 2026-08-01 — 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
tmax00Zbilinear30d26 1 QC4.17 [3.49, 4.90]2.94+2.71 [1.18, 4.30]4.60 [3.96, 5.22]8% [0%, 20%]15%31%-0.09+0.192026-08-05 → 2026-08-30
tmax00Zbilinear90d26 1 QC4.17 [3.37, 5.07]2.94+2.71 [1.10, 4.64]4.60 [3.84, 5.39]8% [0%, 21%]15%31%-0.09+0.192026-08-05 → 2026-08-30
tmax00Zbilinear365d26 1 QC4.17 [3.30, 5.12]2.94+2.71 [0.93, 4.71]4.60 [3.74, 5.40]8% [0%, 22%]15%31%-0.09+0.192026-08-05 → 2026-08-30
tmax00Zbilinearall26 1 QC4.17 [3.26, 5.16]2.94+2.71 [0.98, 4.64]4.60 [3.74, 5.41]8% [0%, 24%]15%31%-0.09+0.192026-08-05 → 2026-08-30
tmax00Znearest30d26 1 QC4.22 [3.54, 4.93]2.84+2.86 [1.39, 4.40]4.61 [3.96, 5.24]4% [0%, 11%]15%23%-0.10+0.222026-08-05 → 2026-08-30
tmax00Znearest90d26 1 QC4.22 [3.43, 5.10]2.84+2.86 [1.28, 4.71]4.61 [3.83, 5.41]4% [0%, 11%]15%23%-0.10+0.222026-08-05 → 2026-08-30
tmax00Znearest365d26 1 QC4.22 [3.35, 5.17]2.84+2.86 [1.14, 4.84]4.61 [3.73, 5.45]4% [0%, 12%]15%23%-0.10+0.222026-08-05 → 2026-08-30
tmax00Znearestall26 1 QC4.22 [3.28, 5.19]2.84+2.86 [1.18, 4.72]4.61 [3.73, 5.46]4% [0%, 12%]15%23%-0.10+0.222026-08-05 → 2026-08-30
tmax12Zbilinear30d26 1 QC3.43 [2.48, 4.47]3.23+1.96 [0.19, 4.13]4.37 [3.28, 5.42]23% [9%, 41%]35%46%+0.11+0.112026-08-05 → 2026-08-30
tmax12Zbilinear90d26 1 QC3.43 [2.34, 4.64]3.23+1.96 [-0.08, 4.52]4.37 [3.15, 5.71]23% [7%, 41%]35%46%+0.11+0.112026-08-05 → 2026-08-30
tmax12Zbilinear365d26 1 QC3.43 [2.31, 4.78]3.23+1.96 [-0.24, 4.59]4.37 [3.04, 5.70]23% [6%, 42%]35%46%+0.11+0.112026-08-05 → 2026-08-30
tmax12Zbilinearall26 1 QC3.43 [2.19, 4.73]3.23+1.96 [-0.15, 4.45]4.37 [2.92, 5.70]23% [7%, 44%]35%46%+0.11+0.112026-08-05 → 2026-08-30
tmax12Znearest30d26 1 QC3.35 [2.26, 4.59]3.15+2.17 [0.38, 4.33]4.36 [3.12, 5.54]27% [12%, 47%]38%54%+0.13+0.132026-08-05 → 2026-08-30
tmax12Znearest90d26 1 QC3.35 [2.17, 4.83]3.15+2.17 [0.10, 4.64]4.36 [2.99, 5.79]27% [9%, 48%]38%54%+0.13+0.132026-08-05 → 2026-08-30
tmax12Znearest365d26 1 QC3.35 [2.13, 4.93]3.15+2.17 [-0.06, 4.76]4.36 [2.86, 5.79]27% [8%, 49%]38%54%+0.13+0.132026-08-05 → 2026-08-30
tmax12Znearestall26 1 QC3.35 [2.06, 4.90]3.15+2.17 [-0.06, 4.68]4.36 [2.80, 5.82]27% [8%, 50%]38%54%+0.13+0.132026-08-05 → 2026-08-30
tmin00Zbilinear30d26 1 QC5.25 [4.51, 5.99]2.06+5.25 [4.51, 5.99]5.88 [5.01, 6.70]8% [0%, 17%]15%19%-1.24+0.142026-08-05 → 2026-08-30
tmin00Zbilinear90d26 1 QC5.25 [4.44, 6.04]2.06+5.25 [4.44, 6.04]5.88 [4.84, 6.77]8% [0%, 18%]15%19%-1.24+0.142026-08-05 → 2026-08-30
tmin00Zbilinear365d26 1 QC5.25 [4.29, 6.08]2.06+5.25 [4.29, 6.08]5.88 [4.69, 6.84]8% [0%, 19%]15%19%-1.24+0.142026-08-05 → 2026-08-30
tmin00Zbilinearall26 1 QC5.25 [4.35, 6.06]2.06+5.25 [4.35, 6.06]5.88 [4.78, 6.70]8% [0%, 19%]15%19%-1.24+0.142026-08-05 → 2026-08-30
tmin00Znearest30d26 1 QC5.58 [4.77, 6.36]2.09+5.58 [4.77, 6.36]6.20 [5.26, 7.09]8% [0%, 17%]12%19%-1.38+0.132026-08-05 → 2026-08-30
tmin00Znearest90d26 1 QC5.58 [4.71, 6.41]2.09+5.58 [4.71, 6.41]6.20 [5.07, 7.14]8% [0%, 18%]12%19%-1.38+0.132026-08-05 → 2026-08-30
tmin00Znearest365d26 1 QC5.58 [4.56, 6.48]2.09+5.58 [4.56, 6.48]6.20 [4.92, 7.21]8% [0%, 19%]12%19%-1.38+0.132026-08-05 → 2026-08-30
tmin00Znearestall26 1 QC5.58 [4.61, 6.43]2.09+5.58 [4.61, 6.43]6.20 [5.03, 7.12]8% [0%, 19%]12%19%-1.38+0.132026-08-05 → 2026-08-30
tmin12Zbilinear30d26 1 QC4.42 [3.71, 5.28]2.20+4.36 [3.59, 5.25]5.07 [4.36, 5.83]15% [7%, 25%]23%27%-0.88+0.082026-08-05 → 2026-08-30
tmin12Zbilinear90d26 1 QC4.42 [3.70, 5.41]2.20+4.36 [3.65, 5.39]5.07 [4.35, 5.92]15% [4%, 25%]23%27%-0.88+0.082026-08-05 → 2026-08-30
tmin12Zbilinear365d26 1 QC4.42 [3.65, 5.39]2.20+4.36 [3.56, 5.39]5.07 [4.30, 5.89]15% [0%, 27%]23%27%-0.88+0.082026-08-05 → 2026-08-30
tmin12Zbilinearall26 1 QC4.42 [3.63, 5.46]2.20+4.36 [3.56, 5.45]5.07 [4.20, 5.94]15% [0%, 26%]23%27%-0.88+0.082026-08-05 → 2026-08-30
tmin12Znearest30d26 1 QC4.67 [3.94, 5.57]2.16+4.66 [3.92, 5.56]5.31 [4.57, 6.12]15% [7%, 25%]19%27%-0.99+0.102026-08-05 → 2026-08-30
tmin12Znearest90d26 1 QC4.67 [3.94, 5.71]2.16+4.66 [3.93, 5.71]5.31 [4.56, 6.22]15% [4%, 25%]19%27%-0.99+0.102026-08-05 → 2026-08-30
tmin12Znearest365d26 1 QC4.67 [3.88, 5.65]2.16+4.66 [3.87, 5.65]5.31 [4.51, 6.18]15% [0%, 27%]19%27%-0.99+0.102026-08-05 → 2026-08-30
tmin12Znearestall26 1 QC4.67 [3.88, 5.72]2.16+4.66 [3.87, 5.72]5.31 [4.41, 6.22]15% [0%, 26%]19%27%-0.99+0.102026-08-05 → 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 NCEP GFS at KNYC, lead day 4, 00Z bilinear tmax+10+50-5-102026-08-05: -1.93 °F2026-08-06: +2.55 °F2026-08-07: +4.62 °F2026-08-08: +5.69 °F2026-08-09: +6.59 °F2026-08-10: +6.48 °F2026-08-11: +6.31 °F2026-08-12: +3.18 °F2026-08-13: -3.83 °F2026-08-14: -5.59 °F2026-08-15: -2.59 °F2026-08-16: +2.69 °F2026-08-17: +6.19 °F2026-08-18: +1.46 °F2026-08-19: +4.02 °F2026-08-20: -5.06 °F2026-08-21: +4.59 °F2026-08-22: +3.51 °F2026-08-23: +0.33 °F2026-08-24: +0.93 °F2026-08-25: +4.67 °F2026-08-26: +2.96 °F2026-08-27: +7.37 °F2026-08-28: +4.36 °F2026-08-29: +3.35 °F2026-08-30: +7.68 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+7.68
2026-08-29+3.35
2026-08-28+4.36
2026-08-27+7.37
2026-08-26+2.96
2026-08-25+4.67
2026-08-24+0.93
2026-08-23+0.33
2026-08-22+3.51
2026-08-21+4.59
2026-08-20-5.06
2026-08-19+4.02
2026-08-18+1.46
2026-08-17+6.19
2026-08-16+2.69
2026-08-15-2.59
2026-08-14-5.59
2026-08-13-3.83
2026-08-12+3.18
2026-08-11+6.31
2026-08-10+6.48
2026-08-09+6.59
2026-08-08+5.69
2026-08-07+4.62
2026-08-06+2.55
2026-08-05-1.93

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KNYC, lead day 4-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 2 days-5 to -4 °F: 0 days-4 to -3 °F: 1 day-3 to -2 °F: 1 day-2 to -1 °F: 1 day-1 to 0 °F: 0 days0 to 1 °F: 2 days1 to 2 °F: 1 day2 to 3 °F: 3 days3 to 4 °F: 3 days4 to 5 °F: 5 days5 to 6 °F: 1 day6 to 7 °F: 4 days7 to 8 °F: 2 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 4.19 · P90 |e| 6.53 °F-100+10 °Fn = 26 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
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.002
-5.00-4.000
-4.00-3.001
-3.00-2.001
-2.00-1.001
-1.00+0.000
+0.00+1.002
+1.00+2.001
+2.00+3.003
+3.00+4.003
+4.00+5.005
+5.00+6.001
+6.00+7.004
+7.00+8.002
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08264.17 +2.71

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26
NCEP GFS2026-08-05 → 2026-08-30 26

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 26 +1.98 [0.94, 3.03] yes
GraphCast (IFS init) 25 +1.38 [0.37, 2.41] yes
ECMWF IFS HRES 20 +0.67 [-0.53, 1.95] no
Persistence (baseline) 26 +0.33 [-0.95, 1.62] no

Cite this page

ShortCastCheck, KNYC gfs lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KNYC/model/gfs/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KNYC (New York Central Park), model gfs, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KNYC/model/gfs/lead/4/

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