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

Denver Intl · NCEP GFS · lead day 8

KDEN · gfs · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 1 QC5.33 [3.40, 6.82]5.15-3.20 [-5.30, -0.99]7.94 [4.09, 10.23]23% [11%, 33%]27%36%+0.31+0.302026-08-09 → 2026-08-30
tmax00Zbilinear90d22 1 QC5.33 [3.26, 6.98]5.15-3.20 [-5.39, -0.77]7.94 [3.97, 10.44]23% [10%, 33%]27%36%+0.31+0.302026-08-09 → 2026-08-30
tmax00Zbilinear365d22 1 QC5.33 [3.18, 6.94]5.15-3.20 [-5.59, -0.78]7.94 [3.90, 10.58]23% [10%, 33%]27%36%+0.31+0.302026-08-09 → 2026-08-30
tmax00Zbilinearall22 1 QC5.33 [3.20, 6.99]5.15-3.20 [-5.43, -0.37]7.94 [3.87, 10.52]23% [9%, 33%]27%36%+0.31+0.302026-08-09 → 2026-08-30
tmax00Znearest30d22 1 QC5.33 [3.67, 6.71]4.78-3.47 [-5.43, -1.37]7.68 [4.23, 9.90]9% [0%, 17%]32%36%+0.31+0.352026-08-09 → 2026-08-30
tmax00Znearest90d22 1 QC5.33 [3.61, 6.79]4.78-3.47 [-5.50, -1.08]7.68 [4.17, 10.13]9% [0%, 16%]32%36%+0.31+0.352026-08-09 → 2026-08-30
tmax00Znearest365d22 1 QC5.33 [3.56, 6.80]4.78-3.47 [-5.78, -1.25]7.68 [4.15, 10.26]9% [0%, 17%]32%36%+0.31+0.352026-08-09 → 2026-08-30
tmax00Znearestall22 1 QC5.33 [3.56, 6.83]4.78-3.47 [-5.54, -0.86]7.68 [4.14, 10.19]9% [0%, 16%]32%36%+0.31+0.352026-08-09 → 2026-08-30
tmax12Zbilinear30d22 1 QC5.38 [3.18, 7.57]5.51-3.35 [-5.06, -1.45]8.08 [4.20, 10.66]18% [0%, 45%]41%45%+0.30+0.252026-08-09 → 2026-08-30
tmax12Zbilinear90d22 1 QC5.38 [3.06, 7.66]5.51-3.35 [-5.11, -0.84]8.08 [3.63, 10.82]18% [0%, 50%]41%45%+0.30+0.252026-08-09 → 2026-08-30
tmax12Zbilinear365d22 1 QC5.38 [2.97, 7.95]5.51-3.35 [-5.30, -0.81]8.08 [3.66, 11.07]18% [0%, 53%]41%45%+0.30+0.252026-08-09 → 2026-08-30
tmax12Zbilinearall22 1 QC5.38 [2.96, 7.54]5.51-3.35 [-5.23, -0.64]8.08 [3.53, 10.82]18% [0%, 50%]41%45%+0.30+0.252026-08-09 → 2026-08-30
tmax12Znearest30d22 1 QC5.50 [3.35, 7.65]5.63-3.28 [-5.09, -1.25]8.19 [4.30, 10.76]9% [0%, 33%]36%45%+0.28+0.242026-08-09 → 2026-08-30
tmax12Znearest90d22 1 QC5.50 [3.28, 7.73]5.63-3.28 [-5.10, -0.71]8.19 [3.83, 10.88]9% [0%, 41%]36%45%+0.28+0.242026-08-09 → 2026-08-30
tmax12Znearest365d22 1 QC5.50 [3.20, 8.07]5.63-3.28 [-5.48, -0.68]8.19 [3.76, 11.17]9% [0%, 39%]36%45%+0.28+0.242026-08-09 → 2026-08-30
tmax12Znearestall22 1 QC5.50 [3.17, 7.60]5.63-3.28 [-5.25, -0.30]8.19 [3.82, 10.87]9% [0%, 40%]36%45%+0.28+0.242026-08-09 → 2026-08-30
tmin00Zbilinear30d22 1 QC5.73 [4.54, 7.30]3.73+4.47 [1.50, 6.99]6.48 [5.34, 7.76]9% [0%, 15%]14%18%+0.01+0.352026-08-09 → 2026-08-30
tmin00Zbilinear90d22 1 QC5.73 [4.48, 7.74]3.73+4.47 [0.74, 7.51]6.48 [5.22, 8.14]9% [0%, 15%]14%18%+0.01+0.352026-08-09 → 2026-08-30
tmin00Zbilinear365d22 1 QC5.73 [4.40, 7.71]3.73+4.47 [0.56, 7.58]6.48 [5.11, 8.09]9% [0%, 15%]14%18%+0.01+0.352026-08-09 → 2026-08-30
tmin00Zbilinearall22 1 QC5.73 [4.42, 7.83]3.73+4.47 [0.35, 7.61]6.48 [5.08, 8.24]9% [0%, 15%]14%18%+0.01+0.352026-08-09 → 2026-08-30
tmin00Znearest30d22 1 QC5.98 [4.69, 7.62]3.84+4.92 [2.11, 7.36]6.80 [5.55, 8.13]9% [0%, 15%]14%18%-0.04+0.342026-08-09 → 2026-08-30
tmin00Znearest90d22 1 QC5.98 [4.57, 8.02]3.84+4.92 [1.34, 7.94]6.80 [5.40, 8.44]9% [0%, 15%]14%18%-0.04+0.342026-08-09 → 2026-08-30
tmin00Znearest365d22 1 QC5.98 [4.45, 8.04]3.84+4.92 [1.23, 8.02]6.80 [5.26, 8.49]9% [0%, 15%]14%18%-0.04+0.342026-08-09 → 2026-08-30
tmin00Znearestall22 1 QC5.98 [4.48, 8.08]3.84+4.92 [0.94, 8.04]6.80 [5.33, 8.49]9% [0%, 15%]14%18%-0.04+0.342026-08-09 → 2026-08-30
tmin12Zbilinear30d22 1 QC5.62 [4.40, 6.82]4.45+3.27 [-0.33, 6.42]6.33 [5.47, 7.24]14% [0%, 40%]18%23%+0.03+0.232026-08-09 → 2026-08-30
tmin12Zbilinear90d22 1 QC5.62 [4.13, 7.26]4.45+3.27 [-1.29, 7.26]6.33 [5.33, 7.46]14% [0%, 50%]18%23%+0.03+0.232026-08-09 → 2026-08-30
tmin12Zbilinear365d22 1 QC5.62 [4.13, 7.36]4.45+3.27 [-1.27, 7.36]6.33 [5.30, 7.47]14% [0%, 50%]18%23%+0.03+0.232026-08-09 → 2026-08-30
tmin12Zbilinearall22 1 QC5.62 [4.23, 7.39]4.45+3.27 [-1.43, 7.39]6.33 [5.41, 7.54]14% [0%, 48%]18%23%+0.03+0.232026-08-09 → 2026-08-30
tmin12Znearest30d22 1 QC5.85 [4.57, 7.09]4.43+3.67 [0.21, 6.77]6.50 [5.63, 7.43]9% [0%, 20%]18%23%-0.01+0.232026-08-09 → 2026-08-30
tmin12Znearest90d22 1 QC5.85 [4.27, 7.75]4.43+3.67 [-0.74, 7.75]6.50 [5.45, 7.84]9% [0%, 22%]18%23%-0.01+0.232026-08-09 → 2026-08-30
tmin12Znearest365d22 1 QC5.85 [4.31, 7.73]4.43+3.67 [-0.85, 7.73]6.50 [5.52, 7.82]9% [0%, 20%]18%23%-0.01+0.232026-08-09 → 2026-08-30
tmin12Znearestall22 1 QC5.85 [4.44, 7.78]4.43+3.67 [-1.03, 7.78]6.50 [5.53, 7.87]9% [0%, 21%]18%23%-0.01+0.232026-08-09 → 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 8, 00Z bilinear tmax+50+250-25-502026-08-09: -2.32 °F2026-08-10: +5.71 °F2026-08-11: -13.92 °F2026-08-12: -13.42 °F2026-08-13: -0.84 °F2026-08-14: +5.63 °F2026-08-15: +5.6 °F2026-08-16: -0.24 °F2026-08-17: -6.32 °F2026-08-18: -3 °F2026-08-19: -5.19 °F2026-08-20: -0.96 °F2026-08-21: -26.67 °F2026-08-22: -1.22 °F2026-08-23: +3.03 °F2026-08-24: -4.48 °F2026-08-25: -2.35 °F2026-08-26: +0.11 °F2026-08-27: -6.15 °F2026-08-28: -6.03 °F2026-08-29: -0.65 °F2026-08-30: +3.38 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+3.38
2026-08-29-0.65
2026-08-28-6.03
2026-08-27-6.15
2026-08-26+0.11
2026-08-25-2.35
2026-08-24-4.48
2026-08-23+3.03
2026-08-22-1.22
2026-08-21-26.67
2026-08-20-0.96
2026-08-19-5.19
2026-08-18-3.00
2026-08-17-6.32
2026-08-16-0.24
2026-08-15+5.60
2026-08-14+5.63
2026-08-13-0.84
2026-08-12-13.42
2026-08-11-13.92
2026-08-10+5.71
2026-08-09-2.32

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KDEN, lead day 8-50 to -45 °F: 0 days-45 to -40 °F: 0 days-40 to -35 °F: 0 days-35 to -30 °F: 0 days-30 to -25 °F: 1 day-25 to -20 °F: 0 days-20 to -15 °F: 0 days-15 to -10 °F: 2 days-10 to -5 °F: 4 days-5 to 0 °F: 9 days0 to 5 °F: 3 days5 to 10 °F: 3 days10 to 15 °F: 0 days15 to 20 °F: 0 days20 to 25 °F: 0 days25 to 30 °F: 0 days30 to 35 °F: 0 days35 to 40 °F: 0 days40 to 45 °F: 0 days45 to 50 °F: 0 daysdashed: P50 |e| 3.93 · P90 |e| 12.71 °F-500+50 °Fn = 22 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
-50.00-45.000
-45.00-40.000
-40.00-35.000
-35.00-30.000
-30.00-25.001
-25.00-20.000
-20.00-15.000
-15.00-10.002
-10.00-5.004
-5.00+0.009
+0.00+5.003
+5.00+10.003
+10.00+15.000
+15.00+20.000
+20.00+25.000
+25.00+30.000
+30.00+35.000
+35.00+40.000
+40.00+45.000
+45.00+50.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08225.33 -3.20

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-09 → 2026-08-30 22
NCEP GFS2026-08-09 → 2026-08-30 22
NCEP GFS2026-08-09 → 2026-08-30 22
NCEP GFS2026-08-09 → 2026-08-30 22

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 22 +0.39 [-1.40, 1.97] no
GraphCast (IFS init) 22 -4.15 [-5.69, -2.97] yes
ECMWF IFS HRES 17 -1.46 [-4.63, 0.70] no
Persistence (baseline) 22 -2.35 [-4.14, -0.60] yes

Cite this page

ShortCastCheck, KDEN gfs lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDEN/model/gfs/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model gfs, lead day 8. 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/8/

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