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 3

KDEN · gfs · lead 3

Target day = initialization date + 3 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
tmax00Zbilinear30d27 1 QC3.99 [3.13, 4.96]3.71-1.95 [-4.06, 1.39]5.03 [4.06, 6.05]22% [10%, 34%]33%44%+0.47+0.512026-08-04 → 2026-08-30
tmax00Zbilinear90d27 1 QC3.99 [3.07, 5.02]3.71-1.95 [-4.07, 2.32]5.03 [3.94, 6.19]22% [9%, 35%]33%44%+0.47+0.512026-08-04 → 2026-08-30
tmax00Zbilinear365d27 1 QC3.99 [3.06, 5.06]3.71-1.95 [-4.15, 2.22]5.03 [3.91, 6.24]22% [7%, 35%]33%44%+0.47+0.512026-08-04 → 2026-08-30
tmax00Zbilinearall27 1 QC3.99 [3.09, 5.31]3.71-1.95 [-4.20, 2.38]5.03 [3.97, 6.51]22% [7%, 36%]33%44%+0.47+0.512026-08-04 → 2026-08-30
tmax00Znearest30d27 1 QC3.98 [3.15, 4.99]3.57-2.13 [-4.19, 1.10]4.96 [4.06, 5.96]30% [15%, 44%]33%44%+0.48+0.532026-08-04 → 2026-08-30
tmax00Znearest90d27 1 QC3.98 [3.08, 5.09]3.57-2.13 [-4.24, 2.05]4.96 [3.95, 6.07]30% [14%, 45%]33%44%+0.48+0.532026-08-04 → 2026-08-30
tmax00Znearest365d27 1 QC3.98 [3.06, 5.06]3.57-2.13 [-4.33, 1.88]4.96 [4.00, 6.06]30% [13%, 45%]33%44%+0.48+0.532026-08-04 → 2026-08-30
tmax00Znearestall27 1 QC3.98 [3.04, 5.33]3.57-2.13 [-4.38, 1.93]4.96 [3.90, 6.36]30% [13%, 45%]33%44%+0.48+0.532026-08-04 → 2026-08-30
tmax12Zbilinear30d27 1 QC3.84 [2.60, 5.27]3.49-2.13 [-4.30, 0.67]5.05 [3.66, 6.47]22% [4%, 43%]37%52%+0.49+0.542026-08-04 → 2026-08-30
tmax12Zbilinear90d27 1 QC3.84 [2.42, 5.43]3.49-2.13 [-4.55, 1.30]5.05 [3.48, 6.64]22% [0%, 48%]37%52%+0.49+0.542026-08-04 → 2026-08-30
tmax12Zbilinear365d27 1 QC3.84 [2.49, 5.57]3.49-2.13 [-4.70, 1.45]5.05 [3.51, 6.58]22% [0%, 46%]37%52%+0.49+0.542026-08-04 → 2026-08-30
tmax12Zbilinearall27 1 QC3.84 [2.45, 5.68]3.49-2.13 [-4.61, 1.38]5.05 [3.33, 6.89]22% [0%, 48%]37%52%+0.49+0.542026-08-04 → 2026-08-30
tmax12Znearest30d27 1 QC3.92 [2.74, 5.43]3.61-2.15 [-4.29, 0.75]5.24 [3.74, 6.78]26% [11%, 44%]41%48%+0.48+0.532026-08-04 → 2026-08-30
tmax12Znearest90d27 1 QC3.92 [2.58, 5.59]3.61-2.15 [-4.63, 1.45]5.24 [3.57, 7.01]26% [9%, 48%]41%48%+0.48+0.532026-08-04 → 2026-08-30
tmax12Znearest365d27 1 QC3.92 [2.60, 5.67]3.61-2.15 [-4.78, 1.42]5.24 [3.57, 6.94]26% [5%, 46%]41%48%+0.48+0.532026-08-04 → 2026-08-30
tmax12Znearestall27 1 QC3.92 [2.57, 5.84]3.61-2.15 [-4.64, 1.59]5.24 [3.45, 7.30]26% [7%, 48%]41%48%+0.48+0.532026-08-04 → 2026-08-30
tmin00Zbilinear30d27 1 QC4.79 [3.28, 6.22]2.73+4.61 [2.87, 6.22]5.71 [4.21, 7.13]11% [0%, 27%]15%37%+0.21+0.552026-08-04 → 2026-08-30
tmin00Zbilinear90d27 1 QC4.79 [3.29, 6.38]2.73+4.61 [2.82, 6.38]5.71 [4.22, 7.30]11% [0%, 27%]15%37%+0.21+0.552026-08-04 → 2026-08-30
tmin00Zbilinear365d27 1 QC4.79 [3.03, 6.42]2.73+4.61 [2.58, 6.42]5.71 [3.76, 7.31]11% [0%, 29%]15%37%+0.21+0.552026-08-04 → 2026-08-30
tmin00Zbilinearall27 1 QC4.79 [3.14, 6.62]2.73+4.61 [2.64, 6.62]5.71 [3.99, 7.39]11% [0%, 29%]15%37%+0.21+0.552026-08-04 → 2026-08-30
tmin00Znearest30d27 1 QC5.10 [3.54, 6.54]2.76+4.99 [3.28, 6.54]6.04 [4.45, 7.48]11% [0%, 22%]19%33%+0.15+0.542026-08-04 → 2026-08-30
tmin00Znearest90d27 1 QC5.10 [3.54, 6.72]2.76+4.99 [3.23, 6.70]6.04 [4.42, 7.69]11% [0%, 23%]19%33%+0.15+0.542026-08-04 → 2026-08-30
tmin00Znearest365d27 1 QC5.10 [3.22, 6.79]2.76+4.99 [2.95, 6.76]6.04 [4.00, 7.74]11% [0%, 23%]19%33%+0.15+0.542026-08-04 → 2026-08-30
tmin00Znearestall27 1 QC5.10 [3.31, 6.98]2.76+4.99 [3.13, 6.98]6.04 [4.23, 7.77]11% [0%, 23%]19%33%+0.15+0.542026-08-04 → 2026-08-30
tmin12Zbilinear30d27 1 QC4.88 [3.74, 6.15]2.53+4.74 [3.41, 6.12]5.73 [4.38, 6.97]7% [0%, 15%]22%33%+0.19+0.582026-08-04 → 2026-08-30
tmin12Zbilinear90d27 1 QC4.88 [3.77, 6.28]2.53+4.74 [3.39, 6.26]5.73 [4.38, 7.13]7% [0%, 15%]22%33%+0.19+0.582026-08-04 → 2026-08-30
tmin12Zbilinear365d27 1 QC4.88 [3.64, 6.28]2.53+4.74 [3.28, 6.24]5.73 [4.16, 7.12]7% [0%, 15%]22%33%+0.19+0.582026-08-04 → 2026-08-30
tmin12Zbilinearall27 1 QC4.88 [3.61, 6.29]2.53+4.74 [3.33, 6.29]5.73 [4.19, 7.15]7% [0%, 16%]22%33%+0.19+0.582026-08-04 → 2026-08-30
tmin12Znearest30d27 1 QC5.39 [4.13, 6.66]2.47+5.30 [3.90, 6.66]6.21 [4.86, 7.43]7% [0%, 15%]15%22%+0.11+0.592026-08-04 → 2026-08-30
tmin12Znearest90d27 1 QC5.39 [4.16, 6.81]2.47+5.30 [3.90, 6.81]6.21 [4.86, 7.59]7% [0%, 15%]15%22%+0.11+0.592026-08-04 → 2026-08-30
tmin12Znearest365d27 1 QC5.39 [4.00, 6.80]2.47+5.30 [3.82, 6.80]6.21 [4.64, 7.54]7% [0%, 15%]15%22%+0.11+0.592026-08-04 → 2026-08-30
tmin12Znearestall27 1 QC5.39 [3.95, 6.77]2.47+5.30 [3.83, 6.77]6.21 [4.66, 7.53]7% [0%, 16%]15%22%+0.11+0.592026-08-04 → 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 3, 00Z bilinear tmax+20+100-10-202026-08-04: +11.6 °F2026-08-05: +5.83 °F2026-08-06: +0.1 °F2026-08-07: +4.17 °F2026-08-08: +0.06 °F2026-08-09: +1.17 °F2026-08-10: +0.94 °F2026-08-11: -3.59 °F2026-08-12: -4.53 °F2026-08-13: -2.88 °F2026-08-14: -6.3 °F2026-08-15: -6.23 °F2026-08-16: -0.27 °F2026-08-17: -9.16 °F2026-08-18: +1.43 °F2026-08-19: -4.17 °F2026-08-20: -2.16 °F2026-08-21: -6.86 °F2026-08-22: +2.24 °F2026-08-23: -8.26 °F2026-08-24: -0.55 °F2026-08-25: -0.01 °F2026-08-26: -8.06 °F2026-08-27: -4.68 °F2026-08-28: -5.9 °F2026-08-29: -1.9 °F2026-08-30: -4.64 °F2026-08-042026-08-30°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 (27 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-4.64
2026-08-29-1.90
2026-08-28-5.90
2026-08-27-4.68
2026-08-26-8.06
2026-08-25-0.01
2026-08-24-0.55
2026-08-23-8.26
2026-08-22+2.24
2026-08-21-6.86
2026-08-20-2.16
2026-08-19-4.17
2026-08-18+1.43
2026-08-17-9.16
2026-08-16-0.27
2026-08-15-6.23
2026-08-14-6.30
2026-08-13-2.88
2026-08-12-4.53
2026-08-11-3.59
2026-08-10+0.94
2026-08-09+1.17
2026-08-08+0.06
2026-08-07+4.17
2026-08-06+0.10
2026-08-05+5.83
2026-08-04+11.60

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KDEN, lead day 3-20 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: 3 days-8 to -6 °F: 3 days-6 to -4 °F: 5 days-4 to -2 °F: 3 days-2 to 0 °F: 4 days0 to 2 °F: 5 days2 to 4 °F: 1 day4 to 6 °F: 2 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| 4.17 · P90 |e| 8.14 °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
-14.00-12.000
-12.00-10.000
-10.00-8.003
-8.00-6.003
-6.00-4.005
-4.00-2.003
-2.00+0.004
+0.00+2.005
+2.00+4.001
+4.00+6.002
+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
2026-08273.99 -1.95

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27

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 27 -0.00 [-1.18, 1.86] no
GraphCast (IFS init) 25 -2.55 [-3.70, -0.86] yes
ECMWF IFS HRES 22 -0.08 [-0.64, 1.65] no
Persistence (baseline) 27 -3.60 [-8.07, -1.33] yes

Cite this page

ShortCastCheck, KDEN gfs lead 3, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDEN/model/gfs/lead/3/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model gfs, lead day 3. 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/3/

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