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

Denver Intl · GraphCast (IFS init) · lead day 5

KDEN · graphcast_ifs · 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, GRAP_v100, starting 2026-01-01 — 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 QC7.46 [6.32, 8.49]3.17-7.46 [-8.49, -6.32]8.40 [6.92, 9.47]4% [0%, 11%]8%16%-0.08+0.542026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC7.46 [6.18, 8.47]3.17-7.46 [-8.47, -6.18]8.40 [6.59, 9.52]4% [0%, 12%]8%16%-0.08+0.542026-08-06 → 2026-08-30
tmax00Zbilinear365d31 1 QC7.61 [6.62, 8.65]3.31-7.61 [-8.65, -6.62]8.61 [7.35, 9.69]6% [0%, 15%]10%16%+0.08+0.612026-01-06 → 2026-08-30
tmax00Zbilinearall31 1 QC7.61 [6.62, 8.61]3.31-7.61 [-8.61, -6.62]8.61 [7.33, 9.68]6% [0%, 15%]10%16%+0.08+0.612026-01-06 → 2026-08-30
tmax00Znearest30d25 1 QC7.57 [6.47, 8.65]3.14-7.57 [-8.65, -6.47]8.50 [7.07, 9.67]8% [0%, 15%]8%16%-0.09+0.552026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC7.57 [6.45, 8.63]3.14-7.57 [-8.63, -6.45]8.50 [6.78, 9.74]8% [0%, 14%]8%16%-0.09+0.552026-08-06 → 2026-08-30
tmax00Znearest365d31 1 QC7.71 [6.74, 8.76]3.24-7.71 [-8.76, -6.74]8.65 [7.43, 9.75]10% [0%, 17%]10%16%+0.07+0.622026-01-06 → 2026-08-30
tmax00Znearestall31 1 QC7.71 [6.78, 8.73]3.24-7.71 [-8.73, -6.78]8.65 [7.42, 9.77]10% [0%, 16%]10%16%+0.07+0.622026-01-06 → 2026-08-30
tmax12Zbilinear30d25 1 QC7.97 [7.06, 8.91]2.82-7.97 [-8.91, -7.06]8.64 [7.56, 9.69]0% [0%, 0%]4%8%-0.15+0.592026-08-06 → 2026-08-30
tmax12Zbilinear90d25 1 QC7.97 [7.02, 8.98]2.82-7.97 [-8.98, -7.02]8.64 [7.49, 9.77]0% [0%, 0%]4%8%-0.15+0.592026-08-06 → 2026-08-30
tmax12Zbilinear365d30 1 QC7.36 [5.62, 8.63]3.00-7.36 [-8.63, -5.62]8.20 [6.60, 9.48]7% [0%, 23%]10%13%+0.14+0.662026-01-06 → 2026-08-30
tmax12Zbilinearall30 1 QC7.36 [5.40, 8.57]3.00-7.36 [-8.57, -5.40]8.20 [6.43, 9.48]7% [0%, 26%]10%13%+0.14+0.662026-01-06 → 2026-08-30
tmax12Znearest30d25 1 QC8.03 [7.15, 8.99]2.76-8.03 [-8.99, -7.15]8.69 [7.58, 9.81]0% [0%, 0%]4%4%-0.16+0.602026-08-06 → 2026-08-30
tmax12Znearest90d25 1 QC8.03 [7.11, 9.10]2.76-8.03 [-9.10, -7.11]8.69 [7.50, 9.88]0% [0%, 0%]4%4%-0.16+0.602026-08-06 → 2026-08-30
tmax12Znearest365d30 1 QC7.45 [5.78, 8.73]2.94-7.45 [-8.73, -5.78]8.26 [6.70, 9.55]3% [0%, 12%]10%10%+0.13+0.672026-01-06 → 2026-08-30
tmax12Znearestall30 1 QC7.45 [5.62, 8.70]2.94-7.45 [-8.70, -5.62]8.26 [6.55, 9.59]3% [0%, 13%]10%10%+0.13+0.672026-01-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC2.56 [1.99, 3.19]1.78+1.91 [1.11, 2.88]2.91 [2.28, 3.56]8% [0%, 16%]36%60%+0.55+0.692026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC2.56 [1.91, 3.23]1.78+1.91 [1.03, 3.09]2.91 [2.22, 3.58]8% [0%, 16%]36%60%+0.55+0.692026-08-06 → 2026-08-30
tmin00Zbilinear365d31 1 QC2.85 [2.10, 3.72]2.09+2.02 [1.17, 3.03]3.27 [2.36, 4.12]6% [0%, 13%]32%52%+0.55+0.662026-01-06 → 2026-08-30
tmin00Zbilinearall31 1 QC2.85 [2.13, 3.71]2.09+2.02 [1.14, 2.97]3.27 [2.41, 4.13]6% [0%, 14%]32%52%+0.55+0.662026-01-06 → 2026-08-30
tmin00Znearest30d25 1 QC2.36 [1.86, 2.89]1.80+1.59 [0.81, 2.58]2.71 [2.15, 3.27]20% [7%, 35%]48%60%+0.58+0.682026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC2.36 [1.80, 2.96]1.80+1.59 [0.74, 2.80]2.71 [2.10, 3.36]20% [7%, 35%]48%60%+0.58+0.682026-08-06 → 2026-08-30
tmin00Znearest365d31 1 QC2.73 [2.00, 3.66]2.15+1.69 [0.85, 2.74]3.15 [2.29, 4.06]16% [2%, 31%]39%52%+0.57+0.652026-01-06 → 2026-08-30
tmin00Znearestall31 1 QC2.73 [2.04, 3.73]2.15+1.69 [0.79, 2.67]3.15 [2.35, 4.14]16% [0%, 31%]39%52%+0.57+0.652026-01-06 → 2026-08-30
tmin12Zbilinear30d25 1 QC2.31 [1.64, 2.93]1.92+1.42 [0.64, 2.36]2.73 [2.05, 3.25]36% [17%, 57%]40%64%+0.59+0.662026-08-06 → 2026-08-30
tmin12Zbilinear90d25 1 QC2.31 [1.57, 3.04]1.92+1.42 [0.42, 2.57]2.73 [1.93, 3.32]36% [15%, 60%]40%64%+0.59+0.662026-08-06 → 2026-08-30
tmin12Zbilinear365d30 1 QC2.89 [1.83, 4.37]2.34+2.08 [0.78, 3.85]3.61 [2.22, 5.12]33% [14%, 54%]37%57%+0.56+0.622026-01-06 → 2026-08-30
tmin12Zbilinearall30 1 QC2.89 [1.87, 4.53]2.34+2.08 [0.84, 4.05]3.61 [2.32, 5.36]33% [15%, 54%]37%57%+0.56+0.622026-01-06 → 2026-08-30
tmin12Znearest30d25 1 QC2.19 [1.58, 2.72]1.93+1.15 [0.38, 2.10]2.60 [1.99, 3.06]32% [16%, 50%]44%68%+0.62+0.662026-08-06 → 2026-08-30
tmin12Znearest90d25 1 QC2.19 [1.51, 2.80]1.93+1.15 [0.26, 2.29]2.60 [1.88, 3.13]32% [14%, 56%]44%68%+0.62+0.662026-08-06 → 2026-08-30
tmin12Znearest365d30 1 QC2.76 [1.70, 4.20]2.37+1.81 [0.53, 3.59]3.47 [2.15, 4.98]27% [8%, 48%]40%60%+0.58+0.622026-01-06 → 2026-08-30
tmin12Znearestall30 1 QC2.76 [1.79, 4.40]2.37+1.81 [0.58, 3.83]3.47 [2.27, 5.21]27% [8%, 46%]40%60%+0.58+0.622026-01-06 → 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 GraphCast (IFS init) at KDEN, lead day 5, 00Z bilinear tmax+20+100-10-202026-08-06: -8.01 °F2026-08-07: -4.1 °F2026-08-08: -5.76 °F2026-08-09: -3.29 °F2026-08-10: -5.19 °F2026-08-11: -8.4 °F2026-08-12: -12.75 °F2026-08-13: -11.88 °F2026-08-14: -11.28 °F2026-08-15: -2.61 °F2026-08-16: -2.01 °F2026-08-17: -8.18 °F2026-08-18: -1 °F2026-08-19: -13.6 °F2026-08-20: -12.09 °F2026-08-21: -14.66 °F2026-08-22: -6.99 °F2026-08-23: -9.58 °F2026-08-24: -5.82 °F2026-08-25: -0.43 °F2026-08-26: -8.34 °F2026-08-27: -7.67 °F2026-08-28: -8.76 °F2026-08-29: -8.8 °F2026-08-30: -5.2 °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
2026-08-30-5.20
2026-08-29-8.80
2026-08-28-8.76
2026-08-27-7.67
2026-08-26-8.34
2026-08-25-0.43
2026-08-24-5.82
2026-08-23-9.58
2026-08-22-6.99
2026-08-21-14.66
2026-08-20-12.09
2026-08-19-13.60
2026-08-18-1.00
2026-08-17-8.18
2026-08-16-2.01
2026-08-15-2.61
2026-08-14-11.28
2026-08-13-11.88
2026-08-12-12.75
2026-08-11-8.40
2026-08-10-5.19
2026-08-09-3.29
2026-08-08-5.76
2026-08-07-4.10
2026-08-06-8.01

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KDEN, lead day 5-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 2 days-14 to -12 °F: 3 days-12 to -10 °F: 4 days-10 to -8 °F: 8 days-8 to -6 °F: 2 days-6 to -4 °F: 6 days-4 to -2 °F: 3 days-2 to 0 °F: 3 days0 to 2 °F: 0 days2 to 4 °F: 0 days4 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| 8.18 · P90 |e| 12.75 °F-200+20 °Fn = 31 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
-16.00-14.002
-14.00-12.003
-12.00-10.004
-10.00-8.008
-8.00-6.002
-6.00-4.006
-4.00-2.003
-2.00+0.003
+0.00+2.000
+2.00+4.000
+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
2026-08257.46 -7.46
2026-0168.26 -8.26

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-06 → 2026-08-30 31
GraphCast (IFS init)2026-01-06 → 2026-08-30 31
GraphCast (IFS init)2026-01-06 → 2026-08-30 30
GraphCast (IFS init)2026-01-06 → 2026-08-30 30

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means GraphCast (IFS init) has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 25 +2.84 [2.23, 3.46] yes
NCEP GFS 25 +2.61 [1.31, 3.96] yes
ECMWF IFS HRES 18 +5.04 [4.10, 6.94] yes
Persistence (baseline) 25 +0.54 [-1.90, 3.79] no

Cite this page

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

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