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

Denver Intl · NCEP GFS · lead day 0

KDEN · 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, 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
tmax00Zbilinear30d30 1 QC3.72 [2.65, 4.73]2.21-3.04 [-4.65, -1.00]4.32 [3.34, 5.14]10% [0%, 20%]20%43%——2026-08-01 → 2026-08-30
tmax00Zbilinear90d30 1 QC3.72 [2.49, 4.79]2.21-3.04 [-4.65, -0.78]4.32 [3.11, 5.18]10% [0%, 20%]20%43%——2026-08-01 → 2026-08-30
tmax00Zbilinear365d30 1 QC3.72 [2.52, 4.85]2.21-3.04 [-4.76, -0.85]4.32 [3.10, 5.25]10% [0%, 19%]20%43%——2026-08-01 → 2026-08-30
tmax00Zbilinearall30 1 QC3.72 [2.50, 4.84]2.21-3.04 [-4.81, -0.77]4.32 [3.11, 5.27]10% [0%, 20%]20%43%——2026-08-01 → 2026-08-30
tmax00Znearest30d30 1 QC3.81 [2.85, 4.74]2.30-3.11 [-4.65, -1.28]4.40 [3.48, 5.18]10% [0%, 20%]27%40%——2026-08-01 → 2026-08-30
tmax00Znearest90d30 1 QC3.81 [2.71, 4.83]2.30-3.11 [-4.71, -0.93]4.40 [3.28, 5.24]10% [0%, 20%]27%40%——2026-08-01 → 2026-08-30
tmax00Znearest365d30 1 QC3.81 [2.68, 4.88]2.30-3.11 [-4.78, -1.01]4.40 [3.31, 5.29]10% [0%, 19%]27%40%——2026-08-01 → 2026-08-30
tmax00Znearestall30 1 QC3.81 [2.64, 4.90]2.30-3.11 [-4.80, -1.02]4.40 [3.32, 5.28]10% [0%, 20%]27%40%——2026-08-01 → 2026-08-30
tmin00Zbilinear30d30 1 QC3.59 [2.75, 4.40]2.49+2.96 [1.69, 4.02]4.22 [3.41, 4.87]10% [0%, 23%]27%53%——2026-08-01 → 2026-08-30
tmin00Zbilinear90d30 1 QC3.59 [2.76, 4.61]2.49+2.96 [1.70, 4.32]4.22 [3.36, 5.03]10% [0%, 23%]27%53%——2026-08-01 → 2026-08-30
tmin00Zbilinear365d30 1 QC3.59 [2.67, 4.77]2.49+2.96 [1.55, 4.53]4.22 [3.28, 5.13]10% [0%, 24%]27%53%——2026-08-01 → 2026-08-30
tmin00Zbilinearall30 1 QC3.59 [2.69, 4.64]2.49+2.96 [1.56, 4.38]4.22 [3.27, 5.09]10% [0%, 24%]27%53%——2026-08-01 → 2026-08-30
tmin00Znearest30d30 1 QC3.95 [3.04, 4.77]2.50+3.56 [2.30, 4.58]4.64 [3.79, 5.29]10% [3%, 17%]23%40%——2026-08-01 → 2026-08-30
tmin00Znearest90d30 1 QC3.95 [3.08, 4.99]2.50+3.56 [2.27, 4.88]4.64 [3.76, 5.47]10% [0%, 17%]23%40%——2026-08-01 → 2026-08-30
tmin00Znearest365d30 1 QC3.95 [3.01, 5.14]2.50+3.56 [2.12, 5.02]4.64 [3.66, 5.49]10% [0%, 16%]23%40%——2026-08-01 → 2026-08-30
tmin00Znearestall30 1 QC3.95 [3.05, 4.95]2.50+3.56 [2.17, 4.86]4.64 [3.73, 5.44]10% [0%, 17%]23%40%——2026-08-01 → 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 KDEN, lead day 0, 00Z bilinear tmax+10+50-5-102026-08-01: -2.27 °F2026-08-02: -4.5 °F2026-08-03: -3.2 °F2026-08-04: +7.36 °F2026-08-05: +2.7 °F2026-08-06: +0.1 °F2026-08-07: -1.14 °F2026-08-08: -2.27 °F2026-08-09: -1.63 °F2026-08-10: -0.49 °F2026-08-11: -2.41 °F2026-08-12: -3.04 °F2026-08-13: -2.22 °F2026-08-14: -8.59 °F2026-08-15: -3.38 °F2026-08-16: -3.93 °F2026-08-17: -4.86 °F2026-08-18: -2.37 °F2026-08-19: -5.88 °F2026-08-20: -4.27 °F2026-08-21: -7.76 °F2026-08-22: -6.95 °F2026-08-23: -6.23 °F2026-08-24: -4.87 °F2026-08-25: -2.9 °F2026-08-26: -0.66 °F2026-08-27: -5.16 °F2026-08-28: -4.83 °F2026-08-29: -4.4 °F2026-08-30: -1.23 °F2026-08-012026-08-30°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 (30 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.23
2026-08-29-4.40
2026-08-28-4.83
2026-08-27-5.16
2026-08-26-0.66
2026-08-25-2.90
2026-08-24-4.87
2026-08-23-6.23
2026-08-22-6.95
2026-08-21-7.76
2026-08-20-4.27
2026-08-19-5.88
2026-08-18-2.37
2026-08-17-4.86
2026-08-16-3.93
2026-08-15-3.38
2026-08-14-8.59
2026-08-13-2.22
2026-08-12-3.04
2026-08-11-2.41
2026-08-10-0.49
2026-08-09-1.63
2026-08-08-2.27
2026-08-07-1.14
2026-08-06+0.10
2026-08-05+2.70
2026-08-04+7.36
2026-08-03-3.20
2026-08-02-4.50
2026-08-01-2.27

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KDEN, lead day 0-10 to -9 °F: 0 days-9 to -8 °F: 1 day-8 to -7 °F: 1 day-7 to -6 °F: 2 days-6 to -5 °F: 2 days-5 to -4 °F: 6 days-4 to -3 °F: 4 days-3 to -2 °F: 6 days-2 to -1 °F: 3 days-1 to 0 °F: 2 days0 to 1 °F: 1 day1 to 2 °F: 0 days2 to 3 °F: 1 day3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 1 day8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 3.29 · P90 |e| 6.99 °F-100+10 °Fn = 30 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
-9.00-8.001
-8.00-7.001
-7.00-6.002
-6.00-5.002
-5.00-4.006
-4.00-3.004
-3.00-2.006
-2.00-1.003
-1.00+0.002
+0.00+1.001
+1.00+2.000
+2.00+3.001
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.001
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08303.72 -3.04

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-01 → 2026-08-30 30
NCEP GFS2026-08-01 → 2026-08-30 30

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 30 -0.22 [-1.32, 0.87] no
Aurora (GFS init) 2 -3.27 [-4.70, -1.85] yes
Aurora (IFS init) 3 -1.31 [-1.77, -0.37] yes
FourCastNet v2 (GFS init) 2 -4.57 [-5.65, -3.49] yes
FourCastNet v2 (IFS init) 3 -2.02 [-2.69, -0.82] yes
GraphCast (GFS init) 2 -2.46 [-3.06, -1.85] yes
GraphCast (IFS init) 28 -1.76 [-2.75, -0.65] yes
ECMWF IFS HRES 25 +0.26 [-1.07, 1.28] no
Pangu-Weather (GFS init) 2 -1.32 [-2.36, -0.28] yes
Pangu-Weather (IFS init) 3 +1.18 [0.82, 1.89] yes

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model 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/KDEN/model/gfs/lead/0/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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