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

Denver Intl · NCEP GFS · lead day 1

KDEN · gfs · lead 1

Target day = initialization date + 1 day. 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
tmax00Zbilinear30d29 1 QC3.85 [2.81, 4.91]2.73-2.77 [-4.69, -0.08]4.71 [3.69, 5.54]17% [3%, 33%]28%45%+0.32+0.522026-08-02 → 2026-08-30
tmax00Zbilinear90d29 1 QC3.85 [2.66, 5.11]2.73-2.77 [-4.92, 0.25]4.71 [3.55, 5.63]17% [0%, 33%]28%45%+0.32+0.522026-08-02 → 2026-08-30
tmax00Zbilinear365d29 1 QC3.85 [2.70, 5.25]2.73-2.77 [-5.19, 0.19]4.71 [3.56, 5.76]17% [0%, 33%]28%45%+0.32+0.522026-08-02 → 2026-08-30
tmax00Zbilinearall29 1 QC3.85 [2.63, 5.15]2.73-2.77 [-5.01, 0.25]4.71 [3.50, 5.77]17% [0%, 33%]28%45%+0.32+0.522026-08-02 → 2026-08-30
tmax00Znearest30d29 1 QC3.95 [2.94, 4.98]2.76-2.80 [-4.68, -0.36]4.81 [3.86, 5.66]14% [3%, 24%]28%45%+0.31+0.522026-08-02 → 2026-08-30
tmax00Znearest90d29 1 QC3.95 [2.93, 5.17]2.76-2.80 [-4.86, -0.01]4.81 [3.76, 5.75]14% [0%, 24%]28%45%+0.31+0.522026-08-02 → 2026-08-30
tmax00Znearest365d29 1 QC3.95 [2.94, 5.35]2.76-2.80 [-5.18, -0.05]4.81 [3.76, 5.77]14% [0%, 26%]28%45%+0.31+0.522026-08-02 → 2026-08-30
tmax00Znearestall29 1 QC3.95 [2.88, 5.25]2.76-2.80 [-4.99, 0.06]4.81 [3.69, 5.84]14% [0%, 25%]28%45%+0.31+0.522026-08-02 → 2026-08-30
tmax12Zbilinear30d29 1 QC3.91 [2.87, 4.89]2.56-2.87 [-4.71, -0.21]4.50 [3.60, 5.29]7% [0%, 20%]24%31%+0.31+0.552026-08-02 → 2026-08-30
tmax12Zbilinear90d29 1 QC3.91 [2.74, 5.03]2.56-2.87 [-4.90, 0.17]4.50 [3.35, 5.34]7% [0%, 19%]24%31%+0.31+0.552026-08-02 → 2026-08-30
tmax12Zbilinear365d29 1 QC3.91 [2.76, 5.07]2.56-2.87 [-5.00, 0.02]4.50 [3.38, 5.42]7% [0%, 19%]24%31%+0.31+0.552026-08-02 → 2026-08-30
tmax12Zbilinearall29 1 QC3.91 [2.70, 5.09]2.56-2.87 [-5.01, 0.13]4.50 [3.35, 5.41]7% [0%, 20%]24%31%+0.31+0.552026-08-02 → 2026-08-30
tmax12Znearest30d29 1 QC3.92 [2.92, 4.86]2.62-2.91 [-4.67, -0.45]4.56 [3.62, 5.35]14% [3%, 24%]24%38%+0.31+0.542026-08-02 → 2026-08-30
tmax12Znearest90d29 1 QC3.92 [2.80, 5.07]2.62-2.91 [-4.87, -0.08]4.56 [3.48, 5.50]14% [0%, 24%]24%38%+0.31+0.542026-08-02 → 2026-08-30
tmax12Znearest365d29 1 QC3.92 [2.80, 5.08]2.62-2.91 [-5.04, -0.05]4.56 [3.48, 5.54]14% [0%, 26%]24%38%+0.31+0.542026-08-02 → 2026-08-30
tmax12Znearestall29 1 QC3.92 [2.76, 5.11]2.62-2.91 [-4.93, -0.14]4.56 [3.46, 5.52]14% [0%, 25%]24%38%+0.31+0.542026-08-02 → 2026-08-30
tmin00Zbilinear30d29 1 QC4.14 [2.97, 5.19]2.81+3.66 [2.10, 4.89]5.00 [3.82, 6.04]10% [0%, 27%]28%41%-0.01+0.322026-08-02 → 2026-08-30
tmin00Zbilinear90d29 1 QC4.14 [3.02, 5.27]2.81+3.66 [2.12, 5.04]5.00 [3.82, 6.10]10% [0%, 26%]28%41%-0.01+0.322026-08-02 → 2026-08-30
tmin00Zbilinear365d29 1 QC4.14 [2.79, 5.24]2.81+3.66 [1.94, 5.04]5.00 [3.64, 6.10]10% [0%, 29%]28%41%-0.01+0.322026-08-02 → 2026-08-30
tmin00Zbilinearall29 1 QC4.14 [2.94, 5.28]2.81+3.66 [2.01, 5.04]5.00 [3.78, 6.18]10% [0%, 29%]28%41%-0.01+0.322026-08-02 → 2026-08-30
tmin00Znearest30d29 1 QC4.66 [3.30, 5.77]2.81+4.30 [2.59, 5.64]5.55 [4.25, 6.63]17% [7%, 28%]21%31%-0.14+0.312026-08-02 → 2026-08-30
tmin00Znearest90d29 1 QC4.66 [3.37, 5.91]2.81+4.30 [2.52, 5.80]5.55 [4.29, 6.70]17% [6%, 30%]21%31%-0.14+0.312026-08-02 → 2026-08-30
tmin00Znearest365d29 1 QC4.66 [3.18, 5.90]2.81+4.30 [2.35, 5.81]5.55 [4.04, 6.69]17% [0%, 29%]21%31%-0.14+0.312026-08-02 → 2026-08-30
tmin00Znearestall29 1 QC4.66 [3.30, 5.94]2.81+4.30 [2.45, 5.79]5.55 [4.24, 6.82]17% [6%, 30%]21%31%-0.14+0.312026-08-02 → 2026-08-30
tmin12Zbilinear30d29 1 QC4.11 [3.36, 4.77]2.48+3.47 [2.16, 4.50]4.69 [3.95, 5.30]3% [0%, 10%]21%34%-0.00+0.402026-08-02 → 2026-08-30
tmin12Zbilinear90d29 1 QC4.11 [3.36, 4.93]2.48+3.47 [2.10, 4.75]4.69 [3.92, 5.38]3% [0%, 11%]21%34%-0.00+0.402026-08-02 → 2026-08-30
tmin12Zbilinear365d29 1 QC4.11 [3.23, 4.90]2.48+3.47 [1.97, 4.77]4.69 [3.81, 5.36]3% [0%, 11%]21%34%-0.00+0.402026-08-02 → 2026-08-30
tmin12Zbilinearall29 1 QC4.11 [3.33, 4.88]2.48+3.47 [2.00, 4.65]4.69 [3.89, 5.40]3% [0%, 10%]21%34%-0.00+0.402026-08-02 → 2026-08-30
tmin12Znearest30d29 1 QC4.45 [3.59, 5.23]2.51+4.02 [2.70, 5.08]5.16 [4.31, 5.91]14% [7%, 21%]21%28%-0.08+0.392026-08-02 → 2026-08-30
tmin12Znearest90d29 1 QC4.45 [3.56, 5.44]2.51+4.02 [2.64, 5.36]5.16 [4.27, 6.03]14% [4%, 24%]21%28%-0.08+0.392026-08-02 → 2026-08-30
tmin12Znearest365d29 1 QC4.45 [3.48, 5.42]2.51+4.02 [2.55, 5.32]5.16 [4.15, 5.99]14% [0%, 25%]21%28%-0.08+0.392026-08-02 → 2026-08-30
tmin12Znearestall29 1 QC4.45 [3.49, 5.43]2.51+4.02 [2.53, 5.30]5.16 [4.19, 6.01]14% [4%, 25%]21%28%-0.08+0.392026-08-02 → 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 1, 00Z bilinear tmax+20+100-10-202026-08-02: -3.27 °F2026-08-03: -1.83 °F2026-08-04: +10.51 °F2026-08-05: +2.57 °F2026-08-06: +0.44 °F2026-08-07: +2.14 °F2026-08-08: -0.71 °F2026-08-09: -0.68 °F2026-08-10: -1.26 °F2026-08-11: -2.33 °F2026-08-12: -5.84 °F2026-08-13: -1.75 °F2026-08-14: -6.78 °F2026-08-15: -0.38 °F2026-08-16: -2.77 °F2026-08-17: -5.63 °F2026-08-18: -0.72 °F2026-08-19: -5.86 °F2026-08-20: -3.27 °F2026-08-21: -8.45 °F2026-08-22: -2.39 °F2026-08-23: -4.95 °F2026-08-24: -3.01 °F2026-08-25: -3.88 °F2026-08-26: -7.9 °F2026-08-27: -8.97 °F2026-08-28: -5.9 °F2026-08-29: -4.21 °F2026-08-30: -3.25 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.25
2026-08-29-4.21
2026-08-28-5.90
2026-08-27-8.97
2026-08-26-7.90
2026-08-25-3.88
2026-08-24-3.01
2026-08-23-4.95
2026-08-22-2.39
2026-08-21-8.45
2026-08-20-3.27
2026-08-19-5.86
2026-08-18-0.72
2026-08-17-5.63
2026-08-16-2.77
2026-08-15-0.38
2026-08-14-6.78
2026-08-13-1.75
2026-08-12-5.84
2026-08-11-2.33
2026-08-10-1.26
2026-08-09-0.68
2026-08-08-0.71
2026-08-07+2.14
2026-08-06+0.44
2026-08-05+2.57
2026-08-04+10.51
2026-08-03-1.83
2026-08-02-3.27

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KDEN, lead day 1-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 0 days-10 to -8 °F: 2 days-8 to -6 °F: 2 days-6 to -4 °F: 6 days-4 to -2 °F: 8 days-2 to 0 °F: 7 days0 to 2 °F: 1 day2 to 4 °F: 2 days4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 0 days10 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| 3.25 · P90 |e| 8.01 °F-200+20 °Fn = 29 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
-14.00-12.000
-12.00-10.000
-10.00-8.002
-8.00-6.002
-6.00-4.006
-4.00-2.008
-2.00+0.007
+0.00+2.001
+2.00+4.002
+4.00+6.000
+6.00+8.000
+8.00+10.000
+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
2026-08293.85 -2.77

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29

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 29 -0.07 [-1.22, 0.96] no
Aurora (GFS init) 1 -1.76 [-1.76, -1.76] yes
Aurora (IFS init) 2 -1.30 [-2.32, -0.27] yes
FourCastNet v2 (GFS init) 1 -0.90 [-0.90, -0.90] yes
FourCastNet v2 (IFS init) 2 -1.83 [-2.97, -0.69] yes
GraphCast (GFS init) 1 +0.19 [0.19, 0.19] yes
GraphCast (IFS init) 27 -2.34 [-3.40, -0.89] yes
ECMWF IFS HRES 22 +0.46 [-1.30, 2.11] no
Pangu-Weather (GFS init) 1 +2.99 [2.99, 2.99] yes
Pangu-Weather (IFS init) 2 +1.93 [0.81, 3.04] yes
Persistence (baseline) 29 -1.84 [-5.00, 0.68] no

Cite this page

ShortCastCheck, KDEN gfs lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDEN/model/gfs/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model gfs, lead day 1. 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/1/

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

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