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

Denver Intl · GraphCast (IFS init) · lead day 7

KDEN · graphcast_ifs · lead 7

Target day = initialization date + 7 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
tmax00Zbilinear30d23 1 QC8.62 [6.95, 10.47]5.07-8.57 [-10.37, -6.91]10.51 [8.22, 12.45]9% [0%, 17%]9%22%-0.04+0.372026-08-08 → 2026-08-30
tmax00Zbilinear90d23 1 QC8.62 [6.63, 10.65]5.07-8.57 [-10.54, -6.63]10.51 [7.74, 12.74]9% [0%, 15%]9%22%-0.04+0.372026-08-08 → 2026-08-30
tmax00Zbilinear365d29 1 QC8.67 [6.77, 10.37]5.23-8.20 [-10.22, -5.65]10.45 [8.06, 12.20]7% [0%, 14%]10%21%+0.10+0.422026-01-08 → 2026-08-30
tmax00Zbilinearall29 1 QC8.67 [6.78, 10.43]5.23-8.20 [-10.25, -5.76]10.45 [8.13, 12.20]7% [0%, 14%]10%21%+0.10+0.422026-01-08 → 2026-08-30
tmax00Znearest30d23 1 QC8.65 [6.94, 10.54]5.15-8.59 [-10.42, -6.90]10.58 [8.24, 12.58]9% [0%, 17%]9%22%-0.05+0.362026-08-08 → 2026-08-30
tmax00Znearest90d23 1 QC8.65 [6.63, 10.75]5.15-8.59 [-10.64, -6.63]10.58 [7.74, 12.86]9% [0%, 15%]9%22%-0.05+0.362026-08-08 → 2026-08-30
tmax00Znearest365d29 1 QC8.62 [6.74, 10.36]5.27-8.15 [-10.21, -5.58]10.42 [7.91, 12.26]7% [0%, 14%]10%21%+0.10+0.412026-01-08 → 2026-08-30
tmax00Znearestall29 1 QC8.62 [6.75, 10.36]5.27-8.15 [-10.23, -5.71]10.42 [8.09, 12.27]7% [0%, 14%]10%21%+0.10+0.412026-01-08 → 2026-08-30
tmax12Zbilinear30d23 1 QC8.72 [7.16, 10.06]3.21-8.72 [-10.06, -7.16]9.63 [7.90, 10.74]0% [0%, 0%]4%13%-0.06+0.602026-08-08 → 2026-08-30
tmax12Zbilinear90d23 1 QC8.72 [7.02, 10.40]3.21-8.72 [-10.40, -7.02]9.63 [7.63, 10.92]0% [0%, 0%]4%13%-0.06+0.602026-08-08 → 2026-08-30
tmax12Zbilinear365d28 1 QC9.01 [7.24, 10.92]3.85-8.89 [-10.86, -6.91]10.11 [8.32, 11.83]0% [0%, 0%]7%14%+0.08+0.572026-01-08 → 2026-08-30
tmax12Zbilinearall28 1 QC9.01 [7.03, 10.79]3.85-8.89 [-10.66, -6.90]10.11 [7.97, 11.77]0% [0%, 0%]7%14%+0.08+0.572026-01-08 → 2026-08-30
tmax12Znearest30d23 1 QC8.75 [7.17, 10.08]3.24-8.75 [-10.08, -7.17]9.67 [7.98, 10.81]0% [0%, 0%]4%13%-0.06+0.602026-08-08 → 2026-08-30
tmax12Znearest90d23 1 QC8.75 [7.06, 10.43]3.24-8.75 [-10.43, -7.06]9.67 [7.68, 10.97]0% [0%, 0%]4%13%-0.06+0.602026-08-08 → 2026-08-30
tmax12Znearest365d28 1 QC9.03 [7.26, 10.93]3.82-8.90 [-10.81, -6.91]10.10 [8.35, 11.77]0% [0%, 0%]7%14%+0.07+0.582026-01-08 → 2026-08-30
tmax12Znearestall28 1 QC9.03 [7.09, 10.77]3.82-8.90 [-10.69, -6.93]10.10 [8.04, 11.70]0% [0%, 0%]7%14%+0.07+0.582026-01-08 → 2026-08-30
tmin00Zbilinear30d23 1 QC2.96 [2.35, 3.62]2.50+1.73 [0.59, 3.05]3.67 [2.88, 4.38]26% [14%, 38%]43%57%+0.47+0.552026-08-08 → 2026-08-30
tmin00Zbilinear90d23 1 QC2.96 [2.34, 3.71]2.50+1.73 [0.41, 3.38]3.67 [2.89, 4.47]26% [13%, 38%]43%57%+0.47+0.552026-08-08 → 2026-08-30
tmin00Zbilinear365d29 1 QC3.14 [2.50, 3.89]2.77+1.64 [0.29, 3.06]3.88 [3.11, 4.59]24% [12%, 37%]41%55%+0.53+0.582026-01-08 → 2026-08-30
tmin00Zbilinearall29 1 QC3.14 [2.52, 3.83]2.77+1.64 [0.35, 3.00]3.88 [3.12, 4.56]24% [12%, 37%]41%55%+0.53+0.582026-01-08 → 2026-08-30
tmin00Znearest30d23 1 QC2.80 [2.27, 3.43]2.44+1.47 [0.39, 2.75]3.51 [2.72, 4.25]22% [12%, 31%]52%61%+0.50+0.572026-08-08 → 2026-08-30
tmin00Znearest90d23 1 QC2.80 [2.25, 3.55]2.44+1.47 [0.25, 3.08]3.51 [2.71, 4.38]22% [11%, 32%]52%61%+0.50+0.572026-08-08 → 2026-08-30
tmin00Znearest365d29 1 QC3.02 [2.39, 3.79]2.74+1.40 [0.09, 2.79]3.78 [2.91, 4.56]24% [14%, 33%]48%59%+0.55+0.582026-01-08 → 2026-08-30
tmin00Znearestall29 1 QC3.02 [2.41, 3.70]2.74+1.40 [0.18, 2.73]3.78 [2.98, 4.56]24% [14%, 33%]48%59%+0.55+0.582026-01-08 → 2026-08-30
tmin12Zbilinear30d23 1 QC2.33 [1.87, 2.82]1.97+1.22 [-0.07, 2.43]2.82 [2.11, 3.34]26% [10%, 46%]48%70%+0.58+0.652026-08-08 → 2026-08-30
tmin12Zbilinear90d23 1 QC2.33 [1.85, 2.83]1.97+1.22 [-0.43, 2.52]2.82 [2.11, 3.39]26% [8%, 50%]48%70%+0.58+0.652026-08-08 → 2026-08-30
tmin12Zbilinear365d28 1 QC2.61 [1.95, 3.45]2.22+1.25 [-0.10, 2.46]3.20 [2.29, 4.05]25% [9%, 44%]46%64%+0.60+0.642026-01-08 → 2026-08-30
tmin12Zbilinearall28 1 QC2.61 [2.01, 3.47]2.22+1.25 [-0.13, 2.40]3.20 [2.41, 4.15]25% [12%, 44%]46%64%+0.60+0.642026-01-08 → 2026-08-30
tmin12Znearest30d23 1 QC2.20 [1.74, 2.66]1.94+0.91 [-0.34, 2.09]2.70 [1.94, 3.30]30% [17%, 43%]52%83%+0.61+0.652026-08-08 → 2026-08-30
tmin12Znearest90d23 1 QC2.20 [1.76, 2.68]1.94+0.91 [-0.71, 2.17]2.70 [1.93, 3.34]30% [14%, 43%]52%83%+0.61+0.652026-08-08 → 2026-08-30
tmin12Znearest365d28 1 QC2.51 [1.82, 3.39]2.23+0.92 [-0.41, 2.12]3.16 [2.09, 4.11]29% [14%, 43%]50%75%+0.62+0.642026-01-08 → 2026-08-30
tmin12Znearestall28 1 QC2.51 [1.90, 3.46]2.23+0.92 [-0.45, 2.06]3.16 [2.23, 4.29]29% [14%, 43%]50%75%+0.62+0.642026-01-08 → 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 7, 00Z bilinear tmax+25+12.50-12.5-252026-08-08: -11.46 °F2026-08-09: -6.56 °F2026-08-10: -2.39 °F2026-08-11: -17.47 °F2026-08-12: -12.88 °F2026-08-13: -2.22 °F2026-08-14: -12.8 °F2026-08-15: -4.23 °F2026-08-16: -3.27 °F2026-08-17: -10.78 °F2026-08-18: +0.63 °F2026-08-19: -23.15 °F2026-08-20: -13.07 °F2026-08-21: -18.78 °F2026-08-22: -5.65 °F2026-08-23: -8.36 °F2026-08-24: -8.48 °F2026-08-25: -2.25 °F2026-08-26: -0.27 °F2026-08-27: -13.33 °F2026-08-28: -10.31 °F2026-08-29: -6.64 °F2026-08-30: -3.34 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.34
2026-08-29-6.64
2026-08-28-10.31
2026-08-27-13.33
2026-08-26-0.27
2026-08-25-2.25
2026-08-24-8.48
2026-08-23-8.36
2026-08-22-5.65
2026-08-21-18.78
2026-08-20-13.07
2026-08-19-23.15
2026-08-18+0.63
2026-08-17-10.78
2026-08-16-3.27
2026-08-15-4.23
2026-08-14-12.80
2026-08-13-2.22
2026-08-12-12.88
2026-08-11-17.47
2026-08-10-2.39
2026-08-09-6.56
2026-08-08-11.46

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KDEN, lead day 7-25 to -22.5 °F: 1 day-22.5 to -20 °F: 0 days-20 to -17.5 °F: 2 days-17.5 to -15 °F: 1 day-15 to -12.5 °F: 4 days-12.5 to -10 °F: 4 days-10 to -7.5 °F: 4 days-7.5 to -5 °F: 3 days-5 to -2.5 °F: 3 days-2.5 to 0 °F: 5 days0 to 2.5 °F: 1 day2.5 to 5 °F: 0 days5 to 7.5 °F: 1 day7.5 to 10 °F: 0 days10 to 12.5 °F: 0 days12.5 to 15 °F: 0 days15 to 17.5 °F: 0 days17.5 to 20 °F: 0 days20 to 22.5 °F: 0 days22.5 to 25 °F: 0 daysdashed: P50 |e| 8.36 · P90 |e| 17.56 °F-250+25 °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
-25.00-22.501
-22.50-20.000
-20.00-17.502
-17.50-15.001
-15.00-12.504
-12.50-10.004
-10.00-7.504
-7.50-5.003
-5.00-2.503
-2.50+0.005
+0.00+2.501
+2.50+5.000
+5.00+7.501
+7.50+10.000
+10.00+12.500
+12.50+15.000
+15.00+17.500
+17.50+20.000
+20.00+22.500
+22.50+25.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08238.62 -8.57
2026-0168.83 -6.77

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-08 → 2026-08-30 29
GraphCast (IFS init)2026-01-08 → 2026-08-30 29
GraphCast (IFS init)2026-01-08 → 2026-08-30 28
GraphCast (IFS init)2026-01-08 → 2026-08-30 28

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 23 +1.97 [0.24, 3.37] yes
NCEP GFS 23 +2.27 [0.06, 4.44] yes
ECMWF IFS HRES 18 +4.12 [1.55, 7.49] yes
Persistence (baseline) 23 +0.36 [-3.07, 3.20] no

Cite this page

ShortCastCheck, KDEN graphcast_ifs lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KDEN/model/graphcast_ifs/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KDEN (Denver Intl), model graphcast_ifs, lead day 7. 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/7/

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