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

All stations (mean of daily station errors) · NCEP GFS · lead day 7

ALL · gfs · lead 7

Target day = initialization date + 7 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, 2 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
tmax00Zbilinear30d23 2 QC3.92 [3.54, 4.18]1.06-1.48 [-1.90, -0.89]5.22 [4.70, 5.54]19% [16%, 22%]36%50%+0.06+0.242026-08-08 → 2026-08-30
tmax00Zbilinear90d23 2 QC3.92 [3.43, 4.20]1.06-1.48 [-1.92, -0.69]5.22 [4.51, 5.54]19% [16%, 23%]36%50%+0.06+0.242026-08-08 → 2026-08-30
tmax00Zbilinear365d23 2 QC3.92 [3.44, 4.22]1.06-1.48 [-1.96, -0.76]5.22 [4.58, 5.56]19% [16%, 23%]36%50%+0.06+0.242026-08-08 → 2026-08-30
tmax00Zbilinearall23 2 QC3.92 [3.43, 4.23]1.06-1.48 [-1.94, -0.76]5.22 [4.39, 5.58]19% [16%, 23%]36%50%+0.06+0.242026-08-08 → 2026-08-30
tmax00Znearest30d23 2 QC4.11 [3.76, 4.34]1.06-1.47 [-1.89, -0.88]5.32 [4.84, 5.62]14% [11%, 18%]33%46%+0.02+0.242026-08-08 → 2026-08-30
tmax00Znearest90d23 2 QC4.11 [3.66, 4.38]1.06-1.47 [-1.90, -0.70]5.32 [4.73, 5.65]14% [10%, 19%]33%46%+0.02+0.242026-08-08 → 2026-08-30
tmax00Znearest365d23 2 QC4.11 [3.70, 4.38]1.06-1.47 [-1.94, -0.74]5.32 [4.78, 5.66]14% [10%, 19%]33%46%+0.02+0.242026-08-08 → 2026-08-30
tmax00Znearestall23 2 QC4.11 [3.64, 4.42]1.06-1.47 [-1.91, -0.75]5.32 [4.64, 5.71]14% [10%, 19%]33%46%+0.02+0.242026-08-08 → 2026-08-30
tmax12Zbilinear30d23 2 QC3.84 [3.63, 4.03]1.13-1.19 [-1.63, -0.48]5.07 [4.76, 5.35]20% [18%, 21%]34%51%+0.08+0.192026-08-08 → 2026-08-30
tmax12Zbilinear90d23 2 QC3.84 [3.64, 4.03]1.13-1.19 [-1.68, -0.18]5.07 [4.75, 5.36]20% [17%, 21%]34%51%+0.08+0.192026-08-08 → 2026-08-30
tmax12Zbilinear365d23 2 QC3.84 [3.60, 4.05]1.13-1.19 [-1.71, -0.28]5.07 [4.74, 5.38]20% [17%, 21%]34%51%+0.08+0.192026-08-08 → 2026-08-30
tmax12Zbilinearall23 2 QC3.84 [3.59, 4.05]1.13-1.19 [-1.67, -0.17]5.07 [4.73, 5.41]20% [17%, 21%]34%51%+0.08+0.192026-08-08 → 2026-08-30
tmax12Znearest30d23 2 QC4.05 [3.85, 4.25]1.18-1.18 [-1.61, -0.46]5.27 [4.95, 5.59]18% [14%, 21%]33%47%+0.03+0.152026-08-08 → 2026-08-30
tmax12Znearest90d23 2 QC4.05 [3.84, 4.26]1.18-1.18 [-1.65, -0.15]5.27 [4.94, 5.62]18% [13%, 21%]33%47%+0.03+0.152026-08-08 → 2026-08-30
tmax12Znearest365d23 2 QC4.05 [3.84, 4.28]1.18-1.18 [-1.68, -0.26]5.27 [4.94, 5.63]18% [13%, 21%]33%47%+0.03+0.152026-08-08 → 2026-08-30
tmax12Znearestall23 2 QC4.05 [3.82, 4.29]1.18-1.18 [-1.67, -0.11]5.27 [4.91, 5.66]18% [12%, 21%]33%47%+0.03+0.152026-08-08 → 2026-08-30
tmin00Zbilinear30d23 2 QC3.69 [3.50, 3.87]0.89+1.68 [1.06, 2.21]4.62 [4.39, 4.82]17% [14%, 19%]34%47%-0.00+0.252026-08-08 → 2026-08-30
tmin00Zbilinear90d23 2 QC3.69 [3.45, 3.89]0.89+1.68 [1.06, 2.27]4.62 [4.34, 4.82]17% [14%, 19%]34%47%-0.00+0.252026-08-08 → 2026-08-30
tmin00Zbilinear365d23 2 QC3.69 [3.47, 3.88]0.89+1.68 [1.02, 2.31]4.62 [4.38, 4.83]17% [14%, 20%]34%47%-0.00+0.252026-08-08 → 2026-08-30
tmin00Zbilinearall23 2 QC3.69 [3.45, 3.90]0.89+1.68 [1.00, 2.34]4.62 [4.34, 4.84]17% [13%, 19%]34%47%-0.00+0.252026-08-08 → 2026-08-30
tmin00Znearest30d23 2 QC3.79 [3.60, 3.96]0.90+1.74 [1.12, 2.29]4.74 [4.48, 4.96]16% [15%, 18%]33%48%-0.03+0.242026-08-08 → 2026-08-30
tmin00Znearest90d23 2 QC3.79 [3.55, 3.97]0.90+1.74 [1.12, 2.35]4.74 [4.43, 4.98]16% [15%, 19%]33%48%-0.03+0.242026-08-08 → 2026-08-30
tmin00Znearest365d23 2 QC3.79 [3.58, 3.96]0.90+1.74 [1.08, 2.39]4.74 [4.46, 4.98]16% [14%, 19%]33%48%-0.03+0.242026-08-08 → 2026-08-30
tmin00Znearestall23 2 QC3.79 [3.56, 3.96]0.90+1.74 [1.05, 2.43]4.74 [4.44, 4.98]16% [15%, 19%]33%48%-0.03+0.242026-08-08 → 2026-08-30
tmin12Zbilinear30d23 2 QC3.68 [3.44, 3.95]0.96+1.68 [1.18, 2.18]4.68 [4.40, 4.97]16% [15%, 18%]34%50%-0.00+0.192026-08-08 → 2026-08-30
tmin12Zbilinear90d23 2 QC3.68 [3.41, 4.00]0.96+1.68 [1.17, 2.26]4.68 [4.37, 5.03]16% [14%, 18%]34%50%-0.00+0.192026-08-08 → 2026-08-30
tmin12Zbilinear365d23 2 QC3.68 [3.40, 4.03]0.96+1.68 [1.15, 2.20]4.68 [4.36, 5.04]16% [14%, 18%]34%50%-0.00+0.192026-08-08 → 2026-08-30
tmin12Zbilinearall23 2 QC3.68 [3.41, 4.03]0.96+1.68 [1.12, 2.26]4.68 [4.38, 5.06]16% [14%, 18%]34%50%-0.00+0.192026-08-08 → 2026-08-30
tmin12Znearest30d23 2 QC3.77 [3.50, 4.06]0.99+1.74 [1.23, 2.22]4.81 [4.50, 5.15]17% [15%, 19%]32%49%-0.03+0.182026-08-08 → 2026-08-30
tmin12Znearest90d23 2 QC3.77 [3.46, 4.10]0.99+1.74 [1.23, 2.30]4.81 [4.46, 5.20]17% [15%, 20%]32%49%-0.03+0.182026-08-08 → 2026-08-30
tmin12Znearest365d23 2 QC3.77 [3.45, 4.16]0.99+1.74 [1.21, 2.27]4.81 [4.45, 5.24]17% [15%, 20%]32%49%-0.03+0.182026-08-08 → 2026-08-30
tmin12Znearestall23 2 QC3.77 [3.46, 4.16]0.99+1.74 [1.18, 2.28]4.81 [4.46, 5.23]17% [15%, 19%]32%49%-0.03+0.182026-08-08 → 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 ALL, lead day 7, 00Z bilinear tmax+5+2.50-2.5-52026-08-08: -0.4 °F2026-08-09: -1.19 °F2026-08-10: +0.92 °F2026-08-11: -0.59 °F2026-08-12: -2.56 °F2026-08-13: +0.16 °F2026-08-14: -2.22 °F2026-08-15: -2.41 °F2026-08-16: -0.65 °F2026-08-17: -3.3 °F2026-08-18: -1.68 °F2026-08-19: -0.43 °F2026-08-20: -2.84 °F2026-08-21: -1.3 °F2026-08-22: +0.09 °F2026-08-23: -1.61 °F2026-08-24: -3.42 °F2026-08-25: -1.27 °F2026-08-26: -4.41 °F2026-08-27: -2.46 °F2026-08-28: -0.52 °F2026-08-29: -0.62 °F2026-08-30: -1.24 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.24
2026-08-29-0.62
2026-08-28-0.52
2026-08-27-2.46
2026-08-26-4.41
2026-08-25-1.27
2026-08-24-3.42
2026-08-23-1.61
2026-08-22+0.09
2026-08-21-1.30
2026-08-20-2.84
2026-08-19-0.43
2026-08-18-1.68
2026-08-17-3.30
2026-08-16-0.65
2026-08-15-2.41
2026-08-14-2.22
2026-08-13+0.16
2026-08-12-2.56
2026-08-11-0.59
2026-08-10+0.92
2026-08-09-1.19
2026-08-08-0.40

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at ALL, lead day 7-5 to -4.5 °F: 0 days-4.5 to -4 °F: 1 day-4 to -3.5 °F: 0 days-3.5 to -3 °F: 2 days-3 to -2.5 °F: 2 days-2.5 to -2 °F: 3 days-2 to -1.5 °F: 2 days-1.5 to -1 °F: 4 days-1 to -0.5 °F: 4 days-0.5 to 0 °F: 2 days0 to 0.5 °F: 2 days0.5 to 1 °F: 1 day1 to 1.5 °F: 0 days1.5 to 2 °F: 0 days2 to 2.5 °F: 0 days2.5 to 3 °F: 0 days3 to 3.5 °F: 0 days3.5 to 4 °F: 0 days4 to 4.5 °F: 0 days4.5 to 5 °F: 0 daysdashed: P50 |e| 1.27 · P90 |e| 3.21 °F-50+5 °Fn = 23 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
-5.00-4.500
-4.50-4.001
-4.00-3.500
-3.50-3.002
-3.00-2.502
-2.50-2.003
-2.00-1.502
-1.50-1.004
-1.00-0.504
-0.50+0.002
+0.00+0.502
+0.50+1.001
+1.00+1.500
+1.50+2.000
+2.00+2.500
+2.50+3.000
+3.00+3.500
+3.50+4.000
+4.00+4.500
+4.50+5.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08231.58 -1.48

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-08 → 2026-08-30 23
NCEP GFS2026-08-08 → 2026-08-30 23
NCEP GFS2026-08-08 → 2026-08-30 23
NCEP GFS2026-08-08 → 2026-08-30 23

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 23 -0.46 [-0.86, -0.16] yes
GraphCast (IFS init) 23 -1.96 [-2.60, -1.26] yes
ECMWF IFS HRES 18 +0.30 [-0.08, 0.93] no
Persistence (baseline) 23 -0.27 [-0.72, 0.06] no

Cite this page

ShortCastCheck, ALL gfs lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/ALL/model/gfs/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: ALL (All stations (mean of daily station errors)), model gfs, lead day 7. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/ALL/model/gfs/lead/7/

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