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

Las Vegas Harry Reid · GraphCast (IFS init) · lead day 5

KLAS · 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, 2 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 2 QC7.11 [5.88, 8.49]2.67-6.81 [-8.45, -5.22]7.81 [6.45, 9.24]4% [0%, 11%]4%8%-0.02+0.612026-08-06 → 2026-08-30
tmax00Zbilinear90d25 2 QC7.11 [5.77, 8.55]2.67-6.81 [-8.55, -5.12]7.81 [6.39, 9.31]4% [0%, 12%]4%8%-0.02+0.612026-08-06 → 2026-08-30
tmax00Zbilinear365d31 2 QC6.07 [3.66, 8.08]3.28-5.68 [-8.02, -3.08]7.07 [4.60, 8.93]10% [0%, 22%]13%23%+0.09+0.512026-01-06 → 2026-08-30
tmax00Zbilinearall31 2 QC6.07 [3.30, 8.02]3.28-5.68 [-7.92, -2.74]7.07 [4.25, 8.86]10% [0%, 25%]13%23%+0.09+0.512026-01-06 → 2026-08-30
tmax00Znearest30d25 2 QC8.26 [6.97, 9.71]2.72-8.05 [-9.69, -6.51]8.92 [7.55, 10.37]0% [0%, 0%]4%8%-0.18+0.602026-08-06 → 2026-08-30
tmax00Znearest90d25 2 QC8.26 [6.86, 9.75]2.72-8.05 [-9.75, -6.42]8.92 [7.39, 10.42]0% [0%, 0%]4%8%-0.18+0.602026-08-06 → 2026-08-30
tmax00Znearest365d31 2 QC7.07 [4.41, 9.24]3.36-6.88 [-9.21, -4.17]8.09 [5.43, 10.01]6% [0%, 21%]13%16%-0.06+0.492026-01-06 → 2026-08-30
tmax00Znearestall31 2 QC7.07 [3.94, 9.18]3.36-6.88 [-9.13, -3.84]8.09 [5.00, 9.93]6% [0%, 24%]13%16%-0.06+0.492026-01-06 → 2026-08-30
tmax12Zbilinear30d25 2 QC7.64 [6.43, 8.73]2.91-7.28 [-8.65, -5.81]8.30 [7.02, 9.33]4% [0%, 11%]4%4%-0.09+0.582026-08-06 → 2026-08-30
tmax12Zbilinear90d25 2 QC7.64 [6.19, 8.75]2.91-7.28 [-8.72, -5.59]8.30 [6.62, 9.31]4% [0%, 12%]4%4%-0.09+0.582026-08-06 → 2026-08-30
tmax12Zbilinear365d30 2 QC6.68 [4.16, 8.47]3.30-6.28 [-8.34, -3.69]7.64 [5.23, 9.09]10% [0%, 25%]13%17%+0.02+0.512026-01-06 → 2026-08-30
tmax12Zbilinearall30 2 QC6.68 [3.49, 8.25]3.30-6.28 [-8.20, -3.03]7.64 [4.28, 9.01]10% [0%, 28%]13%17%+0.02+0.512026-01-06 → 2026-08-30
tmax12Znearest30d25 2 QC8.62 [7.37, 9.76]2.97-8.32 [-9.70, -6.87]9.27 [8.00, 10.33]4% [0%, 11%]4%4%-0.23+0.572026-08-06 → 2026-08-30
tmax12Znearest90d25 2 QC8.62 [7.15, 9.79]2.97-8.32 [-9.77, -6.63]9.27 [7.57, 10.33]4% [0%, 12%]4%4%-0.23+0.572026-08-06 → 2026-08-30
tmax12Znearest365d30 2 QC7.60 [5.00, 9.47]3.39-7.31 [-9.33, -4.70]8.55 [6.07, 10.11]7% [0%, 15%]13%13%-0.11+0.502026-01-06 → 2026-08-30
tmax12Znearestall30 2 QC7.60 [4.40, 9.25]3.39-7.31 [-9.21, -4.00]8.55 [5.07, 9.93]7% [0%, 17%]13%13%-0.11+0.502026-01-06 → 2026-08-30
tmin00Zbilinear30d25 2 QC4.65 [3.63, 5.64]2.70-3.65 [-5.61, -1.17]5.07 [3.96, 5.98]4% [0%, 11%]8%20%+0.30+0.592026-08-06 → 2026-08-30
tmin00Zbilinear90d25 2 QC4.65 [3.56, 5.81]2.70-3.65 [-5.81, -1.18]5.07 [3.90, 6.11]4% [0%, 12%]8%20%+0.30+0.592026-08-06 → 2026-08-30
tmin00Zbilinear365d31 2 QC4.27 [3.09, 5.55]3.58-2.43 [-5.08, 0.61]4.78 [3.60, 5.90]10% [0%, 25%]19%29%+0.34+0.452026-01-06 → 2026-08-30
tmin00Zbilinearall31 2 QC4.27 [3.03, 5.49]3.58-2.43 [-5.13, 0.76]4.78 [3.52, 5.85]10% [0%, 25%]19%29%+0.34+0.452026-01-06 → 2026-08-30
tmin00Znearest30d25 2 QC5.43 [3.88, 6.80]2.67-4.87 [-6.80, -2.41]5.98 [4.58, 7.06]8% [0%, 21%]12%20%+0.18+0.602026-08-06 → 2026-08-30
tmin00Znearest90d25 2 QC5.43 [3.82, 6.96]2.67-4.87 [-6.96, -2.50]5.98 [4.52, 7.21]8% [0%, 22%]12%20%+0.18+0.602026-08-06 → 2026-08-30
tmin00Znearest365d31 2 QC4.78 [2.97, 6.61]3.69-3.56 [-6.29, -0.42]5.53 [3.82, 6.90]16% [0%, 38%]23%29%+0.27+0.432026-01-06 → 2026-08-30
tmin00Znearestall31 2 QC4.78 [2.86, 6.50]3.69-3.56 [-6.27, -0.17]5.53 [3.69, 6.84]16% [0%, 39%]23%29%+0.27+0.432026-01-06 → 2026-08-30
tmin12Zbilinear30d25 2 QC4.37 [3.29, 5.32]2.37-3.81 [-5.32, -1.81]4.87 [3.93, 5.62]12% [0%, 28%]12%24%+0.34+0.642026-08-06 → 2026-08-30
tmin12Zbilinear90d25 2 QC4.37 [3.27, 5.44]2.37-3.81 [-5.44, -1.87]4.87 [3.78, 5.76]12% [0%, 29%]12%24%+0.34+0.642026-08-06 → 2026-08-30
tmin12Zbilinear365d30 2 QC3.94 [2.68, 5.22]2.99-2.88 [-5.02, -0.35]4.55 [3.29, 5.53]20% [0%, 41%]20%33%+0.39+0.542026-01-06 → 2026-08-30
tmin12Zbilinearall30 2 QC3.94 [2.50, 5.14]2.99-2.88 [-5.01, -0.16]4.55 [3.15, 5.50]20% [0%, 44%]20%33%+0.39+0.542026-01-06 → 2026-08-30
tmin12Znearest30d25 2 QC5.18 [3.79, 6.39]2.44-4.85 [-6.39, -2.86]5.73 [4.58, 6.65]8% [0%, 21%]16%20%+0.22+0.632026-08-06 → 2026-08-30
tmin12Znearest90d25 2 QC5.18 [3.76, 6.48]2.44-4.85 [-6.48, -2.90]5.73 [4.38, 6.75]8% [0%, 22%]16%20%+0.22+0.632026-08-06 → 2026-08-30
tmin12Znearest365d30 2 QC4.51 [2.77, 6.19]3.04-3.88 [-6.07, -1.27]5.29 [3.66, 6.48]17% [0%, 38%]27%30%+0.30+0.532026-01-06 → 2026-08-30
tmin12Znearestall30 2 QC4.51 [2.47, 6.13]3.04-3.88 [-6.00, -1.10]5.29 [3.47, 6.44]17% [0%, 42%]27%30%+0.30+0.532026-01-06 → 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 KLAS, lead day 5, 00Z bilinear tmax+20+100-10-202026-08-06: -7.34 °F2026-08-07: -5.33 °F2026-08-08: -6.6 °F2026-08-09: -10.82 °F2026-08-10: -5.27 °F2026-08-11: -6.61 °F2026-08-12: -8.09 °F2026-08-13: -0.6 °F2026-08-14: -10.02 °F2026-08-15: +3.8 °F2026-08-16: -3.79 °F2026-08-17: -7.27 °F2026-08-18: -7.31 °F2026-08-19: -8.19 °F2026-08-20: -4.65 °F2026-08-21: -16.65 °F2026-08-22: -12.15 °F2026-08-23: -9.99 °F2026-08-24: -7.16 °F2026-08-25: -5.83 °F2026-08-26: -6.48 °F2026-08-27: -8.63 °F2026-08-28: -4.36 °F2026-08-29: -8.27 °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
2026-08-29-8.27
2026-08-28-4.36
2026-08-27-8.63
2026-08-26-6.48
2026-08-25-5.83
2026-08-24-7.16
2026-08-23-9.99
2026-08-22-12.15
2026-08-21-16.65
2026-08-20-4.65
2026-08-19-8.19
2026-08-18-7.31
2026-08-17-7.27
2026-08-16-3.79
2026-08-15+3.80
2026-08-14-10.02
2026-08-13-0.60
2026-08-12-8.09
2026-08-11-6.61
2026-08-10-5.27
2026-08-09-10.82
2026-08-08-6.60
2026-08-07-5.33
2026-08-06-7.34

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KLAS, lead day 5-20 to -18 °F: 0 days-18 to -16 °F: 1 day-16 to -14 °F: 0 days-14 to -12 °F: 1 day-12 to -10 °F: 2 days-10 to -8 °F: 5 days-8 to -6 °F: 7 days-6 to -4 °F: 5 days-4 to -2 °F: 5 days-2 to 0 °F: 2 days0 to 2 °F: 2 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| 6.48 · P90 |e| 10.02 °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
-18.00-16.001
-16.00-14.000
-14.00-12.001
-12.00-10.002
-10.00-8.005
-8.00-6.007
-6.00-4.005
-4.00-2.005
-2.00+0.002
+0.00+2.002
+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
2026-08257.11 -6.81
2026-0161.74 -0.99

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 +1.07 [-0.07, 2.41] no
NCEP GFS 25 +2.40 [1.27, 3.66] yes
ECMWF IFS HRES 18 +4.01 [2.85, 4.64] yes
Persistence (baseline) 25 +0.11 [-4.11, 4.29] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), 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/KLAS/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