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 · GraphCast (IFS init) · lead day 2

KDEN · graphcast_ifs · lead 2

Target day = initialization date + 2 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
tmax00Zbilinear30d26 1 QC6.32 [5.52, 6.91]2.04-6.28 [-6.89, -5.50]6.79 [6.05, 7.29]4% [0%, 11%]8%12%+0.17+0.742026-08-03 → 2026-08-30
tmax00Zbilinear90d26 1 QC6.32 [5.40, 6.90]2.04-6.28 [-6.90, -5.39]6.79 [5.82, 7.31]4% [0%, 11%]8%12%+0.17+0.742026-08-03 → 2026-08-30
tmax00Zbilinear365d32 1 QC6.64 [5.86, 7.48]2.05-6.61 [-7.45, -5.82]7.10 [6.31, 7.94]3% [0%, 9%]6%9%+0.11+0.732026-01-03 → 2026-08-30
tmax00Zbilinearall32 1 QC6.64 [5.77, 7.39]2.05-6.61 [-7.37, -5.76]7.10 [6.24, 7.82]3% [0%, 10%]6%9%+0.11+0.732026-01-03 → 2026-08-30
tmax00Znearest30d26 1 QC6.48 [5.59, 7.11]2.06-6.41 [-7.06, -5.56]6.95 [6.09, 7.50]8% [0%, 17%]8%12%+0.15+0.732026-08-03 → 2026-08-30
tmax00Znearest90d26 1 QC6.48 [5.44, 7.12]2.06-6.41 [-7.09, -5.44]6.95 [5.91, 7.49]8% [0%, 17%]8%12%+0.15+0.732026-08-03 → 2026-08-30
tmax00Znearest365d32 1 QC6.81 [6.00, 7.70]2.07-6.75 [-7.62, -5.93]7.26 [6.45, 8.10]6% [0%, 14%]6%9%+0.08+0.722026-01-03 → 2026-08-30
tmax00Znearestall32 1 QC6.81 [5.87, 7.58]2.07-6.75 [-7.58, -5.84]7.26 [6.34, 7.97]6% [0%, 14%]6%9%+0.08+0.722026-01-03 → 2026-08-30
tmax12Zbilinear30d26 1 QC7.03 [6.32, 7.62]1.75-7.03 [-7.62, -6.32]7.35 [6.54, 7.98]0% [0%, 0%]0%4%+0.08+0.772026-08-03 → 2026-08-30
tmax12Zbilinear90d26 1 QC7.03 [6.18, 7.61]1.75-7.03 [-7.61, -6.18]7.35 [6.38, 7.95]0% [0%, 0%]0%4%+0.08+0.772026-08-03 → 2026-08-30
tmax12Zbilinear365d31 1 QC7.22 [6.51, 7.96]1.83-7.22 [-7.96, -6.51]7.56 [6.73, 8.34]0% [0%, 0%]0%3%-0.01+0.752026-01-03 → 2026-08-30
tmax12Zbilinearall31 1 QC7.22 [6.40, 7.91]1.83-7.22 [-7.91, -6.40]7.56 [6.63, 8.29]0% [0%, 0%]0%3%-0.01+0.752026-01-03 → 2026-08-30
tmax12Znearest30d26 1 QC7.08 [6.27, 7.73]1.81-7.08 [-7.73, -6.27]7.42 [6.51, 8.07]0% [0%, 0%]0%4%+0.08+0.772026-08-03 → 2026-08-30
tmax12Znearest90d26 1 QC7.08 [6.13, 7.71]1.81-7.08 [-7.71, -6.13]7.42 [6.35, 8.06]0% [0%, 0%]0%4%+0.08+0.772026-08-03 → 2026-08-30
tmax12Znearest365d31 1 QC7.27 [6.52, 8.04]1.87-7.27 [-8.04, -6.52]7.62 [6.76, 8.42]0% [0%, 0%]0%3%-0.02+0.742026-01-03 → 2026-08-30
tmax12Znearestall31 1 QC7.27 [6.34, 8.01]1.87-7.27 [-8.01, -6.34]7.62 [6.61, 8.38]0% [0%, 0%]0%3%-0.02+0.742026-01-03 → 2026-08-30
tmin00Zbilinear30d26 1 QC2.70 [1.78, 3.74]1.93+2.36 [1.31, 3.60]3.38 [2.31, 4.43]19% [7%, 33%]42%65%+0.45+0.622026-08-03 → 2026-08-30
tmin00Zbilinear90d26 1 QC2.70 [1.80, 3.92]1.93+2.36 [1.31, 3.73]3.38 [2.27, 4.60]19% [5%, 34%]42%65%+0.45+0.622026-08-03 → 2026-08-30
tmin00Zbilinear365d32 1 QC3.21 [2.06, 4.71]2.45+2.65 [1.48, 3.97]4.05 [2.65, 5.45]19% [6%, 32%]38%56%+0.35+0.522026-01-03 → 2026-08-30
tmin00Zbilinearall32 1 QC3.21 [1.98, 4.85]2.45+2.65 [1.47, 4.03]4.05 [2.57, 5.58]19% [6%, 32%]38%56%+0.35+0.522026-01-03 → 2026-08-30
tmin00Znearest30d26 1 QC2.60 [1.77, 3.60]1.99+2.06 [0.93, 3.39]3.20 [2.16, 4.28]27% [8%, 42%]46%65%+0.47+0.602026-08-03 → 2026-08-30
tmin00Znearest90d26 1 QC2.60 [1.77, 3.77]1.99+2.06 [0.93, 3.52]3.20 [2.10, 4.45]27% [8%, 42%]46%65%+0.47+0.602026-08-03 → 2026-08-30
tmin00Znearest365d32 1 QC3.13 [2.01, 4.57]2.49+2.34 [1.15, 3.68]3.87 [2.51, 5.22]22% [0%, 38%]41%56%+0.37+0.512026-01-03 → 2026-08-30
tmin00Znearestall32 1 QC3.13 [1.92, 4.72]2.49+2.34 [1.11, 3.78]3.87 [2.42, 5.37]22% [0%, 38%]41%56%+0.37+0.512026-01-03 → 2026-08-30
tmin12Zbilinear30d26 1 QC2.25 [1.53, 3.06]1.86+1.66 [0.77, 2.64]2.86 [1.91, 3.70]31% [12%, 50%]42%73%+0.54+0.632026-08-03 → 2026-08-30
tmin12Zbilinear90d26 1 QC2.25 [1.57, 3.17]1.86+1.66 [0.74, 2.81]2.86 [1.91, 3.83]31% [10%, 50%]42%73%+0.54+0.632026-08-03 → 2026-08-30
tmin12Zbilinear365d31 1 QC2.78 [1.74, 4.28]2.25+2.21 [1.02, 3.85]3.63 [2.24, 5.20]29% [12%, 47%]39%65%+0.45+0.562026-01-03 → 2026-08-30
tmin12Zbilinearall31 1 QC2.78 [1.68, 4.35]2.25+2.21 [0.94, 4.03]3.63 [2.09, 5.26]29% [11%, 46%]39%65%+0.45+0.562026-01-03 → 2026-08-30
tmin12Znearest30d26 1 QC2.24 [1.58, 2.99]1.94+1.41 [0.43, 2.50]2.79 [1.88, 3.61]27% [12%, 41%]46%81%+0.55+0.612026-08-03 → 2026-08-30
tmin12Znearest90d26 1 QC2.24 [1.60, 3.11]1.94+1.41 [0.41, 2.65]2.79 [1.87, 3.74]27% [10%, 40%]46%81%+0.55+0.612026-08-03 → 2026-08-30
tmin12Znearest365d31 1 QC2.74 [1.77, 4.17]2.31+1.95 [0.70, 3.63]3.49 [2.15, 4.95]23% [6%, 38%]42%71%+0.45+0.552026-01-03 → 2026-08-30
tmin12Znearestall31 1 QC2.74 [1.69, 4.27]2.31+1.95 [0.64, 3.75]3.49 [2.05, 5.01]23% [5%, 36%]42%71%+0.45+0.552026-01-03 → 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 2, 00Z bilinear tmax+20+100-10-202026-08-03: -6.37 °F2026-08-04: -1.26 °F2026-08-05: -7.04 °F2026-08-06: -6.93 °F2026-08-07: -6.36 °F2026-08-08: -7.96 °F2026-08-09: -4.57 °F2026-08-10: -5.09 °F2026-08-11: -6.05 °F2026-08-12: -9.01 °F2026-08-13: -8.05 °F2026-08-14: -10.05 °F2026-08-15: -6.12 °F2026-08-16: -5.3 °F2026-08-17: -8.29 °F2026-08-18: +0.52 °F2026-08-19: -8 °F2026-08-20: -4.04 °F2026-08-21: -9.98 °F2026-08-22: -9.25 °F2026-08-23: -7.9 °F2026-08-24: -5.01 °F2026-08-25: -2.24 °F2026-08-26: -8.05 °F2026-08-27: -7.44 °F2026-08-30: -3.36 °F2026-08-032026-08-30°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 (28 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.36
2026-08-29—
2026-08-28—
2026-08-27-7.44
2026-08-26-8.05
2026-08-25-2.24
2026-08-24-5.01
2026-08-23-7.90
2026-08-22-9.25
2026-08-21-9.98
2026-08-20-4.04
2026-08-19-8.00
2026-08-18+0.52
2026-08-17-8.29
2026-08-16-5.30
2026-08-15-6.12
2026-08-14-10.05
2026-08-13-8.05
2026-08-12-9.01
2026-08-11-6.05
2026-08-10-5.09
2026-08-09-4.57
2026-08-08-7.96
2026-08-07-6.36
2026-08-06-6.93
2026-08-05-7.04
2026-08-04-1.26
2026-08-03-6.37

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KDEN, lead day 2-20 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: 2 days-10 to -8 °F: 8 days-8 to -6 °F: 11 days-6 to -4 °F: 7 days-4 to -2 °F: 2 days-2 to 0 °F: 1 day0 to 2 °F: 1 day2 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| 6.99 · P90 |e| 9.87 °F-200+20 °Fn = 32 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
-12.00-10.002
-10.00-8.008
-8.00-6.0011
-6.00-4.007
-4.00-2.002
-2.00+0.001
+0.00+2.001
+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
2026-08266.32 -6.28
2026-0168.04 -8.04

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-03 → 2026-08-30 32
GraphCast (IFS init)2026-01-03 → 2026-08-30 32
GraphCast (IFS init)2026-01-03 → 2026-08-30 31
GraphCast (IFS init)2026-01-03 → 2026-08-30 31

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 26 +2.26 [1.68, 2.72] yes
Aurora (IFS init) 1 -0.00 [-0.00, -0.00] yes
FourCastNet v2 (IFS init) 1 -0.73 [-0.73, -0.73] yes
NCEP GFS 26 +2.98 [1.23, 4.39] yes
ECMWF IFS HRES 21 +2.81 [1.73, 4.00] yes
Pangu-Weather (IFS init) 1 +2.65 [2.65, 2.65] yes
Persistence (baseline) 26 -1.34 [-7.79, 1.72] no

Cite this page

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

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

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