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

Las Vegas Harry Reid · GraphCast (IFS init) · lead day 1

KLAS · graphcast_ifs · lead 1

Target day = initialization date + 1 day. 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
tmax00Zbilinear30d27 2 QC4.90 [4.38, 5.39]1.64-4.73 [-5.14, -4.29]5.34 [4.60, 6.14]4% [0%, 10%]4%11%-0.54+0.492026-08-02 → 2026-08-30
tmax00Zbilinear90d27 2 QC4.90 [4.31, 5.39]1.64-4.73 [-5.18, -4.25]5.34 [4.52, 6.11]4% [0%, 11%]4%11%-0.54+0.492026-08-02 → 2026-08-30
tmax00Zbilinear365d33 2 QC4.89 [4.43, 5.32]1.56-4.75 [-5.11, -4.38]5.29 [4.65, 6.00]3% [0%, 9%]3%9%-0.52+0.512026-01-02 → 2026-08-30
tmax00Zbilinearall33 2 QC4.89 [4.38, 5.31]1.56-4.75 [-5.14, -4.33]5.29 [4.54, 5.95]3% [0%, 9%]3%9%-0.52+0.512026-01-02 → 2026-08-30
tmax00Znearest30d27 2 QC6.16 [5.81, 6.51]1.51-6.10 [-6.49, -5.73]6.56 [6.03, 7.19]4% [0%, 11%]7%7%-0.93+0.532026-08-02 → 2026-08-30
tmax00Znearest90d27 2 QC6.16 [5.78, 6.53]1.51-6.10 [-6.49, -5.69]6.56 [5.97, 7.20]4% [0%, 11%]7%7%-0.93+0.532026-08-02 → 2026-08-30
tmax00Znearest365d33 2 QC6.07 [5.73, 6.44]1.51-6.02 [-6.38, -5.66]6.45 [5.92, 7.02]3% [0%, 9%]6%6%-0.89+0.532026-01-02 → 2026-08-30
tmax00Znearestall33 2 QC6.07 [5.67, 6.45]1.51-6.02 [-6.43, -5.66]6.45 [5.84, 7.01]3% [0%, 9%]6%6%-0.89+0.532026-01-02 → 2026-08-30
tmax12Zbilinear30d27 2 QC5.77 [4.83, 6.68]1.70-5.65 [-6.43, -4.81]6.15 [5.02, 7.21]0% [0%, 0%]4%7%-0.81+0.472026-08-02 → 2026-08-30
tmax12Zbilinear90d27 2 QC5.77 [4.75, 6.66]1.70-5.65 [-6.46, -4.71]6.15 [4.90, 7.18]0% [0%, 0%]4%7%-0.81+0.472026-08-02 → 2026-08-30
tmax12Zbilinear365d32 2 QC5.77 [4.97, 6.57]1.62-5.67 [-6.37, -4.96]6.12 [5.16, 7.05]0% [0%, 0%]3%6%-0.74+0.512026-01-02 → 2026-08-30
tmax12Zbilinearall32 2 QC5.77 [4.83, 6.53]1.62-5.67 [-6.38, -4.83]6.12 [4.97, 7.04]0% [0%, 0%]3%6%-0.74+0.512026-01-02 → 2026-08-30
tmax12Znearest30d27 2 QC6.71 [5.97, 7.49]1.63-6.67 [-7.43, -5.96]7.07 [6.08, 8.06]4% [0%, 11%]4%4%-1.11+0.492026-08-02 → 2026-08-30
tmax12Znearest90d27 2 QC6.71 [5.89, 7.53]1.63-6.67 [-7.46, -5.87]7.07 [5.99, 8.03]4% [0%, 11%]4%4%-1.11+0.492026-08-02 → 2026-08-30
tmax12Znearest365d32 2 QC6.69 [6.02, 7.40]1.56-6.66 [-7.36, -6.00]7.03 [6.16, 7.89]3% [0%, 9%]3%3%-1.02+0.532026-01-02 → 2026-08-30
tmax12Znearestall32 2 QC6.69 [5.94, 7.40]1.56-6.66 [-7.34, -5.93]7.03 [6.05, 7.88]3% [0%, 9%]3%3%-1.02+0.532026-01-02 → 2026-08-30
tmin00Zbilinear30d27 2 QC3.11 [2.14, 4.20]1.71-2.66 [-4.20, -1.07]3.47 [2.42, 4.44]4% [0%, 10%]26%48%-0.35+0.262026-08-02 → 2026-08-30
tmin00Zbilinear90d27 2 QC3.11 [2.22, 4.41]1.71-2.66 [-4.41, -1.21]3.47 [2.53, 4.58]4% [0%, 11%]26%48%-0.35+0.262026-08-02 → 2026-08-30
tmin00Zbilinear365d33 2 QC2.70 [1.69, 3.78]1.98-2.10 [-3.70, -0.52]3.17 [2.06, 4.09]15% [0%, 38%]39%58%-0.29+0.072026-01-02 → 2026-08-30
tmin00Zbilinearall33 2 QC2.70 [1.74, 3.93]1.98-2.10 [-3.84, -0.57]3.17 [2.13, 4.23]15% [0%, 39%]39%58%-0.29+0.072026-01-02 → 2026-08-30
tmin00Znearest30d27 2 QC4.00 [2.47, 5.44]1.75-3.92 [-5.44, -2.27]4.53 [3.26, 5.60]19% [0%, 47%]19%19%-0.74+0.252026-08-02 → 2026-08-30
tmin00Znearest90d27 2 QC4.00 [2.60, 5.60]1.75-3.92 [-5.60, -2.40]4.53 [3.39, 5.72]19% [0%, 45%]19%19%-0.74+0.252026-08-02 → 2026-08-30
tmin00Znearest365d33 2 QC3.43 [1.90, 4.96]2.11-3.27 [-4.96, -1.59]4.12 [2.68, 5.24]24% [0%, 50%]33%33%-0.64+0.012026-01-02 → 2026-08-30
tmin00Znearestall33 2 QC3.43 [1.92, 5.09]2.11-3.27 [-5.07, -1.58]4.12 [2.76, 5.33]24% [0%, 48%]33%33%-0.64+0.012026-01-02 → 2026-08-30
tmin12Zbilinear30d27 2 QC3.54 [2.36, 4.71]1.55-3.50 [-4.71, -2.22]4.01 [3.03, 4.87]19% [0%, 47%]19%30%-0.54+0.332026-08-02 → 2026-08-30
tmin12Zbilinear90d27 2 QC3.54 [2.44, 4.83]1.55-3.50 [-4.83, -2.31]4.01 [3.16, 4.96]19% [0%, 45%]19%30%-0.54+0.332026-08-02 → 2026-08-30
tmin12Zbilinear365d32 2 QC3.16 [1.94, 4.31]1.88-2.96 [-4.29, -1.51]3.73 [2.67, 4.58]25% [0%, 52%]28%41%-0.47+0.142026-01-02 → 2026-08-30
tmin12Zbilinearall32 2 QC3.16 [2.01, 4.48]1.88-2.96 [-4.43, -1.55]3.73 [2.76, 4.70]25% [0%, 50%]28%41%-0.47+0.142026-01-02 → 2026-08-30
tmin12Znearest30d27 2 QC4.41 [3.02, 5.67]1.60-4.41 [-5.67, -3.02]4.88 [3.81, 5.79]11% [0%, 30%]19%19%-0.92+0.312026-08-02 → 2026-08-30
tmin12Znearest90d27 2 QC4.41 [3.11, 5.76]1.60-4.41 [-5.76, -3.11]4.88 [3.89, 5.89]11% [0%, 29%]19%19%-0.92+0.312026-08-02 → 2026-08-30
tmin12Znearest365d32 2 QC3.90 [2.42, 5.27]2.01-3.83 [-5.27, -2.25]4.53 [3.28, 5.48]19% [0%, 40%]28%28%-0.81+0.082026-01-02 → 2026-08-30
tmin12Znearestall32 2 QC3.90 [2.43, 5.38]2.01-3.83 [-5.36, -2.30]4.53 [3.35, 5.58]19% [0%, 39%]28%28%-0.81+0.082026-01-02 → 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 1, 00Z bilinear tmax+20+100-10-202026-08-02: -3.36 °F2026-08-03: -4.23 °F2026-08-04: -4 °F2026-08-05: -6.61 °F2026-08-06: -2.12 °F2026-08-07: -3.03 °F2026-08-08: -6.37 °F2026-08-09: -5.21 °F2026-08-10: -3.38 °F2026-08-11: -5.5 °F2026-08-12: -9 °F2026-08-13: -0.37 °F2026-08-14: -11.77 °F2026-08-15: +2.31 °F2026-08-16: -4.62 °F2026-08-17: -5.78 °F2026-08-18: -5.24 °F2026-08-19: -4.42 °F2026-08-20: -6.55 °F2026-08-21: -4.85 °F2026-08-22: -4.31 °F2026-08-23: -4.88 °F2026-08-24: -5.74 °F2026-08-25: -5.31 °F2026-08-26: -4.11 °F2026-08-29: -5.54 °F2026-08-30: -3.78 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.78
2026-08-29-5.54
2026-08-28—
2026-08-27—
2026-08-26-4.11
2026-08-25-5.31
2026-08-24-5.74
2026-08-23-4.88
2026-08-22-4.31
2026-08-21-4.85
2026-08-20-6.55
2026-08-19-4.42
2026-08-18-5.24
2026-08-17-5.78
2026-08-16-4.62
2026-08-15+2.31
2026-08-14-11.77
2026-08-13-0.37
2026-08-12-9.00
2026-08-11-5.50
2026-08-10-3.38
2026-08-09-5.21
2026-08-08-6.37
2026-08-07-3.03
2026-08-06-2.12
2026-08-05-6.61
2026-08-04-4.00
2026-08-03-4.23
2026-08-02-3.36

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KLAS, lead day 1-20 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: 1 day-10 to -8 °F: 1 day-8 to -6 °F: 4 days-6 to -4 °F: 18 days-4 to -2 °F: 7 days-2 to 0 °F: 1 day0 to 2 °F: 0 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| 4.85 · P90 |e| 6.6 °F-200+20 °Fn = 33 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
-12.00-10.001
-10.00-8.001
-8.00-6.004
-6.00-4.0018
-4.00-2.007
-2.00+0.001
+0.00+2.000
+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
2026-08274.90 -4.73
2026-0164.80 -4.80

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-02 → 2026-08-30 33
GraphCast (IFS init)2026-01-02 → 2026-08-30 33
GraphCast (IFS init)2026-01-02 → 2026-08-30 32
GraphCast (IFS init)2026-01-02 → 2026-08-30 32

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 27 +0.49 [0.20, 0.85] yes
Aurora (GFS init) 1 -1.34 [-1.34, -1.34] yes
Aurora (IFS init) 2 +0.68 [0.22, 1.15] yes
FourCastNet v2 (GFS init) 1 -0.68 [-0.68, -0.68] yes
FourCastNet v2 (IFS init) 2 -1.41 [-3.74, 0.92] no
NCEP GFS 27 -0.17 [-0.91, 0.50] no
GraphCast (GFS init) 1 -3.86 [-3.86, -3.86] yes
ECMWF IFS HRES 20 +1.25 [0.49, 1.91] yes
Pangu-Weather (GFS init) 1 -1.11 [-1.11, -1.11] yes
Pangu-Weather (IFS init) 2 -1.14 [-1.54, -0.75] yes
Persistence (baseline) 27 +1.72 [0.07, 3.28] yes

Cite this page

ShortCastCheck, KLAS graphcast_ifs lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAS/model/graphcast_ifs/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), model graphcast_ifs, lead day 1. 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/1/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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