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

Las Vegas Harry Reid · GraphCast (IFS init) · lead day 2

KLAS · 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 QC5.63 [4.77, 6.30]1.97-5.31 [-5.88, -4.64]6.08 [5.05, 6.96]0% [0%, 0%]4%15%-0.38+0.512026-08-03 → 2026-08-30
tmax00Zbilinear90d26 1 QC5.63 [4.66, 6.32]1.97-5.31 [-5.93, -4.51]6.08 [4.90, 6.98]0% [0%, 0%]4%15%-0.38+0.512026-08-03 → 2026-08-30
tmax00Zbilinear365d32 1 QC5.51 [4.79, 6.18]1.85-5.24 [-5.79, -4.68]5.92 [5.03, 6.79]0% [0%, 0%]3%16%-0.28+0.572026-01-03 → 2026-08-30
tmax00Zbilinearall32 1 QC5.51 [4.65, 6.12]1.85-5.24 [-5.83, -4.56]5.92 [4.87, 6.77]0% [0%, 0%]3%16%-0.28+0.572026-01-03 → 2026-08-30
tmax00Znearest30d26 1 QC6.71 [6.09, 7.28]1.98-6.57 [-7.15, -5.93]7.21 [6.29, 8.03]4% [0%, 11%]8%8%-0.65+0.512026-08-03 → 2026-08-30
tmax00Znearest90d26 1 QC6.71 [5.98, 7.34]1.98-6.57 [-7.20, -5.84]7.21 [6.23, 8.03]4% [0%, 11%]8%8%-0.65+0.512026-08-03 → 2026-08-30
tmax00Znearest365d32 1 QC6.56 [5.97, 7.14]1.86-6.45 [-7.00, -5.91]7.02 [6.19, 7.87]3% [0%, 10%]6%6%-0.52+0.572026-01-03 → 2026-08-30
tmax00Znearestall32 1 QC6.56 [5.86, 7.13]1.86-6.45 [-7.00, -5.79]7.02 [6.06, 7.83]3% [0%, 10%]6%6%-0.52+0.572026-01-03 → 2026-08-30
tmax12Zbilinear30d26 1 QC6.14 [5.04, 7.00]2.25-6.11 [-6.95, -5.03]6.82 [5.43, 8.02]4% [0%, 11%]4%12%-0.51+0.442026-08-03 → 2026-08-30
tmax12Zbilinear90d26 1 QC6.14 [4.85, 7.02]2.25-6.11 [-6.98, -4.84]6.82 [5.07, 8.01]4% [0%, 11%]4%12%-0.51+0.442026-08-03 → 2026-08-30
tmax12Zbilinear365d31 1 QC5.96 [4.96, 6.81]2.20-5.94 [-6.76, -4.96]6.62 [5.30, 7.77]3% [0%, 9%]3%13%-0.36+0.502026-01-03 → 2026-08-30
tmax12Zbilinearall31 1 QC5.96 [4.81, 6.77]2.20-5.94 [-6.75, -4.81]6.62 [5.05, 7.71]3% [0%, 10%]3%13%-0.36+0.502026-01-03 → 2026-08-30
tmax12Znearest30d26 1 QC7.12 [6.13, 7.98]2.27-7.12 [-7.98, -6.13]7.74 [6.40, 8.94]4% [0%, 11%]4%8%-0.75+0.442026-08-03 → 2026-08-30
tmax12Znearest90d26 1 QC7.12 [5.94, 7.99]2.27-7.12 [-7.99, -5.94]7.74 [6.11, 8.96]4% [0%, 11%]4%8%-0.75+0.442026-08-03 → 2026-08-30
tmax12Znearest365d31 1 QC6.93 [5.98, 7.77]2.21-6.93 [-7.77, -5.98]7.52 [6.24, 8.69]3% [0%, 9%]3%6%-0.58+0.502026-01-03 → 2026-08-30
tmax12Znearestall31 1 QC6.93 [5.81, 7.74]2.21-6.93 [-7.74, -5.81]7.52 [6.05, 8.64]3% [0%, 10%]3%6%-0.58+0.502026-01-03 → 2026-08-30
tmin00Zbilinear30d26 1 QC3.27 [2.39, 4.30]1.84-2.85 [-4.30, -1.36]3.69 [2.87, 4.52]15% [0%, 37%]27%38%+0.15+0.522026-08-03 → 2026-08-30
tmin00Zbilinear90d26 1 QC3.27 [2.48, 4.45]1.84-2.85 [-4.45, -1.49]3.69 [2.97, 4.71]15% [0%, 36%]27%38%+0.15+0.522026-08-03 → 2026-08-30
tmin00Zbilinear365d32 1 QC2.85 [1.90, 3.86]2.03-2.30 [-3.82, -0.80]3.36 [2.43, 4.18]22% [0%, 43%]38%50%+0.19+0.432026-01-03 → 2026-08-30
tmin00Zbilinearall32 1 QC2.85 [1.97, 3.99]2.03-2.30 [-3.98, -0.88]3.36 [2.48, 4.27]22% [0%, 43%]38%50%+0.19+0.432026-01-03 → 2026-08-30
tmin00Znearest30d26 1 QC4.26 [3.03, 5.46]1.85-4.09 [-5.46, -2.58]4.72 [3.71, 5.65]12% [0%, 30%]15%19%-0.11+0.522026-08-03 → 2026-08-30
tmin00Znearest90d26 1 QC4.26 [3.12, 5.66]1.85-4.09 [-5.66, -2.71]4.72 [3.85, 5.80]12% [0%, 29%]15%19%-0.11+0.522026-08-03 → 2026-08-30
tmin00Znearest365d32 1 QC3.69 [2.31, 5.10]2.10-3.49 [-5.09, -1.93]4.30 [3.09, 5.29]19% [0%, 39%]28%34%-0.05+0.412026-01-03 → 2026-08-30
tmin00Znearestall32 1 QC3.69 [2.39, 5.20]2.10-3.49 [-5.20, -2.00]4.30 [3.18, 5.42]19% [0%, 37%]28%34%-0.05+0.412026-01-03 → 2026-08-30
tmin12Zbilinear30d26 1 QC3.48 [2.43, 4.57]1.60-3.42 [-4.57, -2.26]3.98 [3.19, 4.80]19% [0%, 50%]19%38%+0.09+0.592026-08-03 → 2026-08-30
tmin12Zbilinear90d26 1 QC3.48 [2.55, 4.75]1.60-3.42 [-4.75, -2.38]3.98 [3.27, 4.94]19% [0%, 46%]19%38%+0.09+0.592026-08-03 → 2026-08-30
tmin12Zbilinear365d31 1 QC3.07 [1.94, 4.19]1.87-2.88 [-4.19, -1.47]3.66 [2.66, 4.47]26% [0%, 55%]32%48%+0.14+0.482026-01-03 → 2026-08-30
tmin12Zbilinearall31 1 QC3.07 [2.05, 4.30]1.87-2.88 [-4.30, -1.56]3.66 [2.73, 4.56]26% [0%, 52%]32%48%+0.14+0.482026-01-03 → 2026-08-30
tmin12Znearest30d26 1 QC4.36 [3.19, 5.48]1.66-4.36 [-5.48, -3.19]4.85 [4.01, 5.67]12% [0%, 30%]19%19%-0.13+0.572026-08-03 → 2026-08-30
tmin12Znearest90d26 1 QC4.36 [3.28, 5.64]1.66-4.36 [-5.64, -3.28]4.85 [4.12, 5.82]12% [0%, 29%]19%19%-0.13+0.572026-08-03 → 2026-08-30
tmin12Znearest365d31 1 QC3.83 [2.42, 5.14]1.92-3.81 [-5.13, -2.38]4.47 [3.36, 5.39]16% [0%, 33%]29%32%-0.07+0.472026-01-03 → 2026-08-30
tmin12Znearestall31 1 QC3.83 [2.53, 5.24]1.92-3.81 [-5.24, -2.47]4.47 [3.40, 5.46]16% [0%, 33%]29%32%-0.07+0.472026-01-03 → 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 KLAS, lead day 2, 00Z bilinear tmax+20+100-10-202026-08-03: -4.22 °F2026-08-04: -3.74 °F2026-08-05: -5.68 °F2026-08-06: -2.79 °F2026-08-07: -2.61 °F2026-08-08: -7.53 °F2026-08-09: -7.24 °F2026-08-10: -5.43 °F2026-08-11: -6.17 °F2026-08-12: -12.12 °F2026-08-13: +1.47 °F2026-08-14: -10.66 °F2026-08-15: +2.72 °F2026-08-16: -6.14 °F2026-08-17: -6.08 °F2026-08-18: -5.66 °F2026-08-19: -4.62 °F2026-08-20: -8.33 °F2026-08-21: -5.85 °F2026-08-22: -4.72 °F2026-08-23: -6.16 °F2026-08-24: -5.56 °F2026-08-25: -4.43 °F2026-08-26: -5.45 °F2026-08-27: -6.46 °F2026-08-30: -4.52 °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
2026-08-30-4.52
2026-08-29—
2026-08-28—
2026-08-27-6.46
2026-08-26-5.45
2026-08-25-4.43
2026-08-24-5.56
2026-08-23-6.16
2026-08-22-4.72
2026-08-21-5.85
2026-08-20-8.33
2026-08-19-4.62
2026-08-18-5.66
2026-08-17-6.08
2026-08-16-6.14
2026-08-15+2.72
2026-08-14-10.66
2026-08-13+1.47
2026-08-12-12.12
2026-08-11-6.17
2026-08-10-5.43
2026-08-09-7.24
2026-08-08-7.53
2026-08-07-2.61
2026-08-06-2.79
2026-08-05-5.68
2026-08-04-3.74
2026-08-03-4.22

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KLAS, 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: 1 day-12 to -10 °F: 1 day-10 to -8 °F: 1 day-8 to -6 °F: 8 days-6 to -4 °F: 15 days-4 to -2 °F: 4 days-2 to 0 °F: 0 days0 to 2 °F: 1 day2 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| 5.5 · P90 |e| 7.63 °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
-14.00-12.001
-12.00-10.001
-10.00-8.001
-8.00-6.008
-6.00-4.0015
-4.00-2.004
-2.00+0.000
+0.00+2.001
+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
2026-08265.63 -5.31
2026-0164.97 -4.97

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 +0.69 [0.25, 1.05] yes
Aurora (IFS init) 1 +0.60 [0.60, 0.60] yes
FourCastNet v2 (IFS init) 1 -1.40 [-1.40, -1.40] yes
NCEP GFS 26 +1.06 [-0.54, 2.72] no
ECMWF IFS HRES 21 +2.55 [1.60, 3.46] yes
Pangu-Weather (IFS init) 1 -0.99 [-0.99, -0.99] yes
Persistence (baseline) 26 +1.55 [-0.06, 3.22] no

Cite this page

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

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