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

Las Vegas Harry Reid · GraphCast (IFS init) · lead day 8

KLAS · graphcast_ifs · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d22 2 QC10.46 [7.57, 13.15]5.43-9.90 [-12.98, -6.45]11.92 [9.21, 13.95]0% [0%, 0%]5%14%-0.17+0.382026-08-09 → 2026-08-30
tmax00Zbilinear90d22 2 QC10.46 [7.05, 13.68]5.43-9.90 [-13.68, -5.74]11.92 [8.77, 14.37]0% [0%, 0%]5%14%-0.17+0.382026-08-09 → 2026-08-30
tmax00Zbilinear365d28 2 QC8.82 [4.58, 12.15]5.81-8.26 [-11.92, -3.68]10.70 [6.31, 13.29]4% [0%, 13%]14%29%-0.10+0.272026-01-09 → 2026-08-30
tmax00Zbilinearall28 2 QC8.82 [3.87, 12.64]5.81-8.26 [-12.49, -3.02]10.70 [5.13, 13.65]4% [0%, 14%]14%29%-0.10+0.272026-01-09 → 2026-08-30
tmax00Znearest30d22 2 QC11.36 [8.35, 14.12]5.39-11.04 [-14.04, -7.67]12.85 [10.13, 14.91]0% [0%, 0%]5%14%-0.27+0.392026-08-09 → 2026-08-30
tmax00Znearest90d22 2 QC11.36 [7.68, 14.74]5.39-11.04 [-14.74, -6.92]12.85 [9.62, 15.35]0% [0%, 0%]5%14%-0.27+0.392026-08-09 → 2026-08-30
tmax00Znearest365d28 2 QC9.65 [5.13, 13.16]5.84-9.35 [-13.02, -4.64]11.55 [6.96, 14.21]4% [0%, 14%]11%21%-0.21+0.272026-01-09 → 2026-08-30
tmax00Znearestall28 2 QC9.65 [4.44, 13.67]5.84-9.35 [-13.59, -3.91]11.55 [5.52, 14.58]4% [0%, 14%]11%21%-0.21+0.272026-01-09 → 2026-08-30
tmax12Zbilinear30d22 2 QC9.30 [6.61, 11.71]4.63-8.62 [-11.57, -5.22]10.42 [7.98, 12.23]0% [0%, 0%]5%18%-0.04+0.472026-08-09 → 2026-08-30
tmax12Zbilinear90d22 2 QC9.30 [5.64, 11.91]4.63-8.62 [-11.90, -4.49]10.42 [6.93, 12.25]0% [0%, 0%]5%18%-0.04+0.472026-08-09 → 2026-08-30
tmax12Zbilinear365d27 2 QC7.81 [3.25, 11.15]5.33-7.16 [-11.07, -2.37]9.44 [4.60, 11.68]11% [0%, 39%]19%30%-0.01+0.312026-01-09 → 2026-08-30
tmax12Zbilinearall27 2 QC7.81 [2.25, 11.13]5.33-7.16 [-10.91, -1.29]9.44 [2.50, 11.94]11% [0%, 43%]19%30%-0.01+0.312026-01-09 → 2026-08-30
tmax12Znearest30d22 2 QC10.10 [7.01, 12.79]4.61-9.70 [-12.66, -6.30]11.31 [8.71, 13.21]0% [0%, 0%]14%18%-0.13+0.482026-08-09 → 2026-08-30
tmax12Znearest90d22 2 QC10.10 [6.21, 12.99]4.61-9.70 [-12.96, -5.66]11.31 [7.65, 13.25]0% [0%, 0%]14%18%-0.13+0.482026-08-09 → 2026-08-30
tmax12Znearest365d27 2 QC8.54 [3.71, 12.06]5.36-8.22 [-12.04, -3.32]10.26 [5.07, 12.68]7% [0%, 26%]26%30%-0.10+0.302026-01-09 → 2026-08-30
tmax12Znearestall27 2 QC8.54 [2.27, 12.03]5.36-8.22 [-11.98, -2.15]10.26 [2.92, 12.80]7% [0%, 29%]26%30%-0.10+0.302026-01-09 → 2026-08-30
tmin00Zbilinear30d22 2 QC6.04 [4.08, 7.98]4.20-4.88 [-7.98, -1.33]7.25 [5.40, 8.78]14% [0%, 35%]18%27%+0.26+0.492026-08-09 → 2026-08-30
tmin00Zbilinear90d22 2 QC6.04 [3.88, 8.28]4.20-4.88 [-8.28, -1.19]7.25 [5.20, 8.96]14% [0%, 39%]18%27%+0.26+0.492026-08-09 → 2026-08-30
tmin00Zbilinear365d28 2 QC5.91 [4.30, 7.53]5.41-2.66 [-7.04, 2.34]6.95 [5.23, 8.33]11% [0%, 32%]14%21%+0.25+0.292026-01-09 → 2026-08-30
tmin00Zbilinearall28 2 QC5.91 [4.23, 7.77]5.41-2.66 [-7.29, 3.11]6.95 [5.18, 8.57]11% [0%, 30%]14%21%+0.25+0.292026-01-09 → 2026-08-30
tmin00Znearest30d22 2 QC6.96 [4.74, 9.10]4.21-6.03 [-9.10, -2.50]8.08 [5.89, 9.82]5% [0%, 13%]18%23%+0.15+0.482026-08-09 → 2026-08-30
tmin00Znearest90d22 2 QC6.96 [4.63, 9.48]4.21-6.03 [-9.48, -2.34]8.08 [5.79, 10.07]5% [0%, 14%]18%23%+0.15+0.482026-08-09 → 2026-08-30
tmin00Znearest365d28 2 QC6.59 [4.70, 8.56]5.68-3.62 [-8.13, 1.73]7.60 [5.39, 9.33]4% [0%, 11%]14%18%+0.16+0.262026-01-09 → 2026-08-30
tmin00Znearestall28 2 QC6.59 [4.63, 8.78]5.68-3.62 [-8.40, 2.59]7.60 [5.39, 9.53]4% [0%, 10%]14%18%+0.16+0.262026-01-09 → 2026-08-30
tmin12Zbilinear30d22 2 QC5.41 [3.41, 7.28]3.25-4.71 [-7.28, -1.86]6.34 [4.34, 7.78]9% [0%, 23%]18%27%+0.34+0.602026-08-09 → 2026-08-30
tmin12Zbilinear90d22 2 QC5.41 [3.36, 7.44]3.25-4.71 [-7.44, -1.69]6.34 [4.32, 7.91]9% [0%, 25%]18%27%+0.34+0.602026-08-09 → 2026-08-30
tmin12Zbilinear365d27 2 QC5.39 [3.71, 7.04]4.65-2.86 [-6.51, 1.96]6.21 [4.50, 7.54]7% [0%, 20%]15%22%+0.33+0.402026-01-09 → 2026-08-30
tmin12Zbilinearall27 2 QC5.39 [3.55, 7.27]4.65-2.86 [-6.73, 2.68]6.21 [4.39, 7.75]7% [0%, 20%]15%22%+0.33+0.402026-01-09 → 2026-08-30
tmin12Znearest30d22 2 QC6.32 [4.06, 8.39]3.30-5.81 [-8.39, -2.89]7.23 [5.00, 8.85]9% [0%, 23%]18%18%+0.23+0.602026-08-09 → 2026-08-30
tmin12Znearest90d22 2 QC6.32 [3.95, 8.58]3.30-5.81 [-8.58, -2.70]7.23 [4.80, 8.99]9% [0%, 22%]18%18%+0.23+0.602026-08-09 → 2026-08-30
tmin12Znearest365d27 2 QC6.08 [4.14, 7.93]4.86-3.81 [-7.65, 1.26]6.92 [4.90, 8.53]7% [0%, 19%]15%19%+0.25+0.372026-01-09 → 2026-08-30
tmin12Znearestall27 2 QC6.08 [3.94, 8.22]4.86-3.81 [-7.86, 2.12]6.92 [4.74, 8.78]7% [0%, 20%]15%19%+0.25+0.372026-01-09 → 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 8, 00Z bilinear tmax+25+12.50-12.5-252026-08-09: -15.71 °F2026-08-10: -14.34 °F2026-08-11: -11.46 °F2026-08-12: -14.87 °F2026-08-13: -1.25 °F2026-08-14: -3.11 °F2026-08-15: +3.79 °F2026-08-16: -7.75 °F2026-08-17: -10.03 °F2026-08-18: -9.11 °F2026-08-19: -19.02 °F2026-08-20: -9.32 °F2026-08-21: -14.63 °F2026-08-22: -8.09 °F2026-08-23: -9.9 °F2026-08-24: -20.89 °F2026-08-25: -16.23 °F2026-08-26: -16.32 °F2026-08-27: -15.19 °F2026-08-28: -3.93 °F2026-08-29: -2.85 °F2026-08-30: +2.35 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30+2.35
2026-08-29-2.85
2026-08-28-3.93
2026-08-27-15.19
2026-08-26-16.32
2026-08-25-16.23
2026-08-24-20.89
2026-08-23-9.90
2026-08-22-8.09
2026-08-21-14.63
2026-08-20-9.32
2026-08-19-19.02
2026-08-18-9.11
2026-08-17-10.03
2026-08-16-7.75
2026-08-15+3.79
2026-08-14-3.11
2026-08-13-1.25
2026-08-12-14.87
2026-08-11-11.46
2026-08-10-14.34
2026-08-09-15.71

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KLAS, lead day 8-25 to -22.5 °F: 0 days-22.5 to -20 °F: 1 day-20 to -17.5 °F: 1 day-17.5 to -15 °F: 4 days-15 to -12.5 °F: 3 days-12.5 to -10 °F: 2 days-10 to -7.5 °F: 6 days-7.5 to -5 °F: 0 days-5 to -2.5 °F: 4 days-2.5 to 0 °F: 4 days0 to 2.5 °F: 2 days2.5 to 5 °F: 1 day5 to 7.5 °F: 0 days7.5 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| 8.6 · P90 |e| 16.25 °F-250+25 °Fn = 28 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
-25.00-22.500
-22.50-20.001
-20.00-17.501
-17.50-15.004
-15.00-12.503
-12.50-10.002
-10.00-7.506
-7.50-5.000
-5.00-2.504
-2.50+0.004
+0.00+2.502
+2.50+5.001
+5.00+7.500
+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
2026-082210.46 -9.90
2026-0162.80 -2.25

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 28
GraphCast (IFS init)2026-01-09 → 2026-08-30 27
GraphCast (IFS init)2026-01-09 → 2026-08-30 27

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 22 +2.21 [-0.66, 6.46] no
NCEP GFS 22 +4.47 [1.58, 7.79] yes
ECMWF IFS HRES 17 +4.59 [0.37, 9.52] yes
Persistence (baseline) 22 +1.51 [-3.64, 6.82] no

Cite this page

ShortCastCheck, KLAS graphcast_ifs lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAS/model/graphcast_ifs/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), model graphcast_ifs, lead day 8. 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/8/

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