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 5

KDEN · gfs · lead 5

Target day = initialization date + 5 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
tmax00Zbilinear30d25 1 QC4.84 [2.87, 6.27]3.86-4.07 [-5.38, -2.08]6.07 [3.85, 7.42]20% [4%, 43%]32%40%+0.30+0.442026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC4.84 [2.43, 6.40]3.86-4.07 [-5.44, -1.69]6.07 [3.21, 7.57]20% [0%, 50%]32%40%+0.30+0.442026-08-06 → 2026-08-30
tmax00Zbilinear365d25 1 QC4.84 [2.40, 6.56]3.86-4.07 [-5.54, -1.59]6.07 [3.12, 7.67]20% [0%, 50%]32%40%+0.30+0.442026-08-06 → 2026-08-30
tmax00Zbilinearall25 1 QC4.84 [2.41, 6.39]3.86-4.07 [-5.40, -1.64]6.07 [3.10, 7.61]20% [0%, 50%]32%40%+0.30+0.442026-08-06 → 2026-08-30
tmax00Znearest30d25 1 QC4.73 [2.74, 6.19]3.70-4.07 [-5.33, -2.17]5.95 [3.63, 7.37]16% [0%, 37%]28%48%+0.32+0.472026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC4.73 [2.27, 6.28]3.70-4.07 [-5.50, -1.74]5.95 [2.98, 7.55]16% [0%, 45%]28%48%+0.32+0.472026-08-06 → 2026-08-30
tmax00Znearest365d25 1 QC4.73 [2.20, 6.43]3.70-4.07 [-5.56, -1.64]5.95 [3.02, 7.74]16% [0%, 43%]28%48%+0.32+0.472026-08-06 → 2026-08-30
tmax00Znearestall25 1 QC4.73 [2.30, 6.34]3.70-4.07 [-5.50, -1.72]5.95 [2.98, 7.60]16% [0%, 43%]28%48%+0.32+0.472026-08-06 → 2026-08-30
tmax12Zbilinear30d25 1 QC3.94 [2.60, 5.31]3.24-3.47 [-5.03, -1.76]5.28 [3.32, 6.67]20% [11%, 30%]40%52%+0.43+0.532026-08-06 → 2026-08-30
tmax12Zbilinear90d25 1 QC3.94 [2.44, 5.31]3.24-3.47 [-5.06, -1.37]5.28 [3.10, 6.72]20% [10%, 31%]40%52%+0.43+0.532026-08-06 → 2026-08-30
tmax12Zbilinear365d25 1 QC3.94 [2.35, 5.47]3.24-3.47 [-5.18, -1.34]5.28 [2.95, 6.84]20% [8%, 33%]40%52%+0.43+0.532026-08-06 → 2026-08-30
tmax12Zbilinearall25 1 QC3.94 [2.39, 5.45]3.24-3.47 [-5.15, -1.29]5.28 [2.97, 6.78]20% [10%, 33%]40%52%+0.43+0.532026-08-06 → 2026-08-30
tmax12Znearest30d25 1 QC3.81 [2.56, 5.18]3.05-3.46 [-4.91, -1.94]5.07 [3.32, 6.61]20% [6%, 33%]44%52%+0.45+0.562026-08-06 → 2026-08-30
tmax12Znearest90d25 1 QC3.81 [2.41, 5.21]3.05-3.46 [-4.94, -1.67]5.07 [3.07, 6.71]20% [5%, 33%]44%52%+0.45+0.562026-08-06 → 2026-08-30
tmax12Znearest365d25 1 QC3.81 [2.33, 5.50]3.05-3.46 [-5.21, -1.61]5.07 [2.92, 6.89]20% [0%, 35%]44%52%+0.45+0.562026-08-06 → 2026-08-30
tmax12Znearestall25 1 QC3.81 [2.33, 5.27]3.05-3.46 [-5.13, -1.56]5.07 [2.96, 6.77]20% [0%, 35%]44%52%+0.45+0.562026-08-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC4.51 [3.83, 5.24]2.62+3.53 [1.83, 5.11]4.94 [4.24, 5.56]4% [0%, 12%]20%24%+0.21+0.542026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC4.51 [3.76, 5.43]2.62+3.53 [1.54, 5.43]4.94 [4.19, 5.69]4% [0%, 12%]20%24%+0.21+0.542026-08-06 → 2026-08-30
tmin00Zbilinear365d25 1 QC4.51 [3.71, 5.51]2.62+3.53 [1.54, 5.51]4.94 [4.10, 5.76]4% [0%, 12%]20%24%+0.21+0.542026-08-06 → 2026-08-30
tmin00Zbilinearall25 1 QC4.51 [3.73, 5.46]2.62+3.53 [1.48, 5.46]4.94 [4.15, 5.73]4% [0%, 12%]20%24%+0.21+0.542026-08-06 → 2026-08-30
tmin00Znearest30d25 1 QC4.93 [4.09, 5.75]2.63+4.15 [2.41, 5.73]5.36 [4.54, 6.07]4% [0%, 12%]8%28%+0.13+0.542026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC4.93 [4.04, 6.02]2.63+4.15 [2.19, 6.02]5.36 [4.48, 6.24]4% [0%, 12%]8%28%+0.13+0.542026-08-06 → 2026-08-30
tmin00Znearest365d25 1 QC4.93 [3.96, 6.08]2.63+4.15 [2.08, 6.08]5.36 [4.38, 6.29]4% [0%, 12%]8%28%+0.13+0.542026-08-06 → 2026-08-30
tmin00Znearestall25 1 QC4.93 [3.96, 6.02]2.63+4.15 [2.06, 6.02]5.36 [4.37, 6.25]4% [0%, 12%]8%28%+0.13+0.542026-08-06 → 2026-08-30
tmin12Zbilinear30d25 1 QC4.55 [3.64, 5.48]2.65+4.03 [2.83, 5.30]5.10 [4.19, 5.90]4% [0%, 11%]24%36%+0.20+0.532026-08-06 → 2026-08-30
tmin12Zbilinear90d25 1 QC4.55 [3.51, 5.66]2.65+4.03 [2.61, 5.60]5.10 [4.03, 6.05]4% [0%, 12%]24%36%+0.20+0.532026-08-06 → 2026-08-30
tmin12Zbilinear365d25 1 QC4.55 [3.48, 5.67]2.65+4.03 [2.60, 5.66]5.10 [4.00, 6.07]4% [0%, 12%]24%36%+0.20+0.532026-08-06 → 2026-08-30
tmin12Zbilinearall25 1 QC4.55 [3.49, 5.65]2.65+4.03 [2.60, 5.52]5.10 [3.98, 6.04]4% [0%, 12%]24%36%+0.20+0.532026-08-06 → 2026-08-30
tmin12Znearest30d25 1 QC4.67 [3.76, 5.56]2.45+4.32 [3.28, 5.46]5.24 [4.34, 6.00]4% [0%, 11%]8%36%+0.18+0.572026-08-06 → 2026-08-30
tmin12Znearest90d25 1 QC4.67 [3.66, 5.75]2.45+4.32 [3.10, 5.71]5.24 [4.21, 6.13]4% [0%, 12%]8%36%+0.18+0.572026-08-06 → 2026-08-30
tmin12Znearest365d25 1 QC4.67 [3.61, 5.76]2.45+4.32 [3.09, 5.75]5.24 [4.19, 6.12]4% [0%, 12%]8%36%+0.18+0.572026-08-06 → 2026-08-30
tmin12Znearestall25 1 QC4.67 [3.61, 5.70]2.45+4.32 [3.02, 5.66]5.24 [4.18, 6.10]4% [0%, 12%]8%36%+0.18+0.572026-08-06 → 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 5, 00Z bilinear tmax+20+100-10-202026-08-06: -1.45 °F2026-08-07: +0.86 °F2026-08-08: +0.9 °F2026-08-09: +0.98 °F2026-08-10: -5.4 °F2026-08-11: -0.27 °F2026-08-12: -7.1 °F2026-08-13: -7.65 °F2026-08-14: -9.9 °F2026-08-15: -4 °F2026-08-16: +3.15 °F2026-08-17: -9.35 °F2026-08-18: +1.7 °F2026-08-19: -11.68 °F2026-08-20: -8.47 °F2026-08-21: -12.92 °F2026-08-22: +0.58 °F2026-08-23: -4.19 °F2026-08-24: -2.46 °F2026-08-25: +1.43 °F2026-08-26: -3.44 °F2026-08-27: -8.03 °F2026-08-28: -6.82 °F2026-08-29: -5.65 °F2026-08-30: -2.67 °F2026-08-062026-08-30°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 (25 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.67
2026-08-29-5.65
2026-08-28-6.82
2026-08-27-8.03
2026-08-26-3.44
2026-08-25+1.43
2026-08-24-2.46
2026-08-23-4.19
2026-08-22+0.58
2026-08-21-12.92
2026-08-20-8.47
2026-08-19-11.68
2026-08-18+1.70
2026-08-17-9.35
2026-08-16+3.15
2026-08-15-4.00
2026-08-14-9.90
2026-08-13-7.65
2026-08-12-7.10
2026-08-11-0.27
2026-08-10-5.40
2026-08-09+0.98
2026-08-08+0.90
2026-08-07+0.86
2026-08-06-1.45

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KDEN, lead day 5-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 1 day-10 to -8 °F: 4 days-8 to -6 °F: 3 days-6 to -4 °F: 3 days-4 to -2 °F: 4 days-2 to 0 °F: 2 days0 to 2 °F: 6 days2 to 4 °F: 1 day4 to 6 °F: 0 days6 to 8 °F: 0 days8 to 10 °F: 0 days10 to 12 °F: 0 days12 to 14 °F: 0 days14 to 16 °F: 0 days16 to 18 °F: 0 days18 to 20 °F: 0 daysdashed: P50 |e| 4 · P90 |e| 9.68 °F-200+20 °Fn = 25 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
-14.00-12.001
-12.00-10.001
-10.00-8.004
-8.00-6.003
-6.00-4.003
-4.00-2.004
-2.00+0.002
+0.00+2.006
+2.00+4.001
+4.00+6.000
+6.00+8.000
+8.00+10.000
+10.00+12.000
+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
2026-08254.84 -4.07

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25

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 25 +0.22 [-1.38, 1.43] no
GraphCast (IFS init) 25 -2.61 [-3.96, -1.31] yes
ECMWF IFS HRES 18 +2.31 [0.95, 3.55] yes
Persistence (baseline) 25 -2.08 [-5.08, 1.05] no

Cite this page

ShortCastCheck, KDEN gfs lead 5, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDEN/model/gfs/lead/5/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model gfs, lead day 5. 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/5/

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