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 6

KLAS · graphcast_ifs · lead 6

Target day = initialization date + 6 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
tmax00Zbilinear30d24 2 QC8.40 [6.43, 10.29]3.41-7.84 [-10.21, -5.57]9.19 [7.17, 10.98]0% [0%, 0%]0%4%-0.07+0.562026-08-07 → 2026-08-30
tmax00Zbilinear90d24 2 QC8.40 [6.08, 10.57]3.41-7.84 [-10.57, -5.32]9.19 [6.80, 11.18]0% [0%, 0%]0%4%-0.07+0.562026-08-07 → 2026-08-30
tmax00Zbilinear365d30 2 QC6.98 [3.48, 9.63]4.30-6.35 [-9.51, -2.90]8.24 [4.86, 10.54]3% [0%, 12%]17%23%+0.04+0.402026-01-07 → 2026-08-30
tmax00Zbilinearall30 2 QC6.98 [3.34, 9.75]4.30-6.35 [-9.60, -2.67]8.24 [4.45, 10.56]3% [0%, 12%]17%23%+0.04+0.402026-01-07 → 2026-08-30
tmax00Znearest30d24 2 QC9.37 [7.40, 11.40]3.38-9.06 [-11.36, -6.82]10.20 [8.18, 12.00]4% [0%, 11%]4%8%-0.19+0.562026-08-07 → 2026-08-30
tmax00Znearest90d24 2 QC9.37 [7.07, 11.77]3.38-9.06 [-11.77, -6.62]10.20 [7.78, 12.22]4% [0%, 12%]4%8%-0.19+0.562026-08-07 → 2026-08-30
tmax00Znearest365d30 2 QC7.82 [4.19, 10.65]4.36-7.50 [-10.63, -3.93]9.15 [5.60, 11.53]7% [0%, 15%]17%27%-0.08+0.392026-01-07 → 2026-08-30
tmax00Znearestall30 2 QC7.82 [4.01, 10.74]4.36-7.50 [-10.68, -3.69]9.15 [5.23, 11.52]7% [0%, 14%]17%27%-0.08+0.392026-01-07 → 2026-08-30
tmax12Zbilinear30d24 2 QC8.09 [6.33, 9.88]3.46-7.61 [-9.75, -5.28]8.88 [6.93, 10.56]4% [0%, 11%]4%8%-0.03+0.552026-08-07 → 2026-08-30
tmax12Zbilinear90d24 2 QC8.09 [6.01, 10.06]3.46-7.61 [-10.04, -5.09]8.88 [6.57, 10.69]4% [0%, 12%]4%8%-0.03+0.552026-08-07 → 2026-08-30
tmax12Zbilinear365d29 2 QC7.14 [4.28, 9.40]3.91-6.46 [-9.34, -3.31]8.18 [5.22, 10.18]7% [0%, 17%]14%17%+0.03+0.452026-01-07 → 2026-08-30
tmax12Zbilinearall29 2 QC7.14 [4.07, 9.47]3.91-6.46 [-9.40, -2.84]8.18 [4.73, 10.27]7% [0%, 17%]14%17%+0.03+0.452026-01-07 → 2026-08-30
tmax12Znearest30d24 2 QC9.04 [7.17, 10.87]3.47-8.72 [-10.82, -6.48]9.83 [7.88, 11.46]4% [0%, 11%]4%4%-0.15+0.552026-08-07 → 2026-08-30
tmax12Znearest90d24 2 QC9.04 [6.81, 11.05]3.47-8.72 [-11.01, -6.28]9.83 [7.44, 11.61]4% [0%, 12%]4%4%-0.15+0.552026-08-07 → 2026-08-30
tmax12Znearest365d29 2 QC8.01 [5.18, 10.42]3.98-7.54 [-10.32, -4.32]9.05 [5.98, 11.11]3% [0%, 10%]7%14%-0.09+0.442026-01-07 → 2026-08-30
tmax12Znearestall29 2 QC8.01 [4.76, 10.48]3.98-7.54 [-10.43, -3.81]9.05 [5.34, 11.22]3% [0%, 11%]7%14%-0.09+0.442026-01-07 → 2026-08-30
tmin00Zbilinear30d24 2 QC4.82 [3.61, 5.97]3.03-3.92 [-5.96, -1.36]5.42 [4.13, 6.53]4% [0%, 11%]8%25%+0.35+0.592026-08-07 → 2026-08-30
tmin00Zbilinear90d24 2 QC4.82 [3.62, 6.09]3.03-3.92 [-6.09, -1.34]5.42 [4.11, 6.56]4% [0%, 12%]8%25%+0.35+0.592026-08-07 → 2026-08-30
tmin00Zbilinear365d30 2 QC4.65 [3.49, 5.79]4.03-2.35 [-5.42, 1.21]5.25 [4.06, 6.29]7% [0%, 16%]13%27%+0.36+0.422026-01-07 → 2026-08-30
tmin00Zbilinearall30 2 QC4.65 [3.46, 5.84]4.03-2.35 [-5.47, 1.76]5.25 [3.97, 6.37]7% [0%, 15%]13%27%+0.36+0.422026-01-07 → 2026-08-30
tmin00Znearest30d24 2 QC5.64 [3.86, 7.19]3.06-5.14 [-7.19, -2.58]6.36 [4.68, 7.65]4% [0%, 12%]17%21%+0.24+0.582026-08-07 → 2026-08-30
tmin00Znearest90d24 2 QC5.64 [3.89, 7.29]3.06-5.14 [-7.29, -2.60]6.36 [4.74, 7.71]4% [0%, 12%]17%21%+0.24+0.582026-08-07 → 2026-08-30
tmin00Znearest365d30 2 QC5.21 [3.53, 6.83]4.19-3.42 [-6.60, 0.44]6.00 [4.40, 7.32]10% [0%, 27%]20%27%+0.28+0.402026-01-07 → 2026-08-30
tmin00Znearestall30 2 QC5.21 [3.46, 6.88]4.19-3.42 [-6.65, 0.96]6.00 [4.33, 7.37]10% [0%, 27%]20%27%+0.28+0.402026-01-07 → 2026-08-30
tmin12Zbilinear30d24 2 QC4.84 [3.38, 6.09]2.73-4.33 [-6.09, -2.08]5.46 [4.18, 6.38]12% [0%, 30%]17%21%+0.35+0.632026-08-07 → 2026-08-30
tmin12Zbilinear90d24 2 QC4.84 [3.40, 6.14]2.73-4.33 [-6.14, -2.12]5.46 [4.23, 6.43]12% [0%, 29%]17%21%+0.35+0.632026-08-07 → 2026-08-30
tmin12Zbilinear365d29 2 QC4.71 [3.40, 5.96]3.82-2.88 [-5.74, 0.71]5.30 [4.06, 6.25]10% [0%, 27%]17%24%+0.36+0.462026-01-07 → 2026-08-30
tmin12Zbilinearall29 2 QC4.71 [3.29, 5.94]3.82-2.88 [-5.79, 1.20]5.30 [3.96, 6.28]10% [0%, 27%]17%24%+0.36+0.462026-01-07 → 2026-08-30
tmin12Znearest30d24 2 QC5.63 [3.73, 7.20]2.76-5.43 [-7.20, -3.14]6.39 [4.94, 7.44]17% [0%, 40%]17%21%+0.24+0.622026-08-07 → 2026-08-30
tmin12Znearest90d24 2 QC5.63 [3.74, 7.24]2.76-5.43 [-7.24, -3.23]6.39 [4.95, 7.50]17% [0%, 39%]17%21%+0.24+0.622026-08-07 → 2026-08-30
tmin12Znearest365d29 2 QC5.26 [3.48, 7.01]3.97-3.89 [-6.91, -0.12]6.05 [4.53, 7.25]17% [0%, 38%]21%24%+0.29+0.442026-01-07 → 2026-08-30
tmin12Znearestall29 2 QC5.26 [3.37, 6.96]3.97-3.89 [-6.82, 0.36]6.05 [4.41, 7.21]17% [0%, 39%]21%24%+0.29+0.442026-01-07 → 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 6, 00Z bilinear tmax+20+100-10-202026-08-07: -12.03 °F2026-08-08: -8.55 °F2026-08-09: -7.51 °F2026-08-10: -7.24 °F2026-08-11: -7.47 °F2026-08-12: -12.11 °F2026-08-13: +2.18 °F2026-08-14: -7.42 °F2026-08-15: +4.46 °F2026-08-16: -7.72 °F2026-08-17: -9.92 °F2026-08-18: -10.4 °F2026-08-19: -8.37 °F2026-08-20: -6.5 °F2026-08-21: -11.82 °F2026-08-22: -18.16 °F2026-08-23: -11.78 °F2026-08-24: -14.06 °F2026-08-25: -6.23 °F2026-08-26: -7.77 °F2026-08-27: -10.02 °F2026-08-28: -3.03 °F2026-08-29: -3.29 °F2026-08-30: -3.53 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.53
2026-08-29-3.29
2026-08-28-3.03
2026-08-27-10.02
2026-08-26-7.77
2026-08-25-6.23
2026-08-24-14.06
2026-08-23-11.78
2026-08-22-18.16
2026-08-21-11.82
2026-08-20-6.50
2026-08-19-8.37
2026-08-18-10.40
2026-08-17-9.92
2026-08-16-7.72
2026-08-15+4.46
2026-08-14-7.42
2026-08-13+2.18
2026-08-12-12.11
2026-08-11-7.47
2026-08-10-7.24
2026-08-09-7.51
2026-08-08-8.55
2026-08-07-12.03

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KLAS, lead day 6-20 to -18 °F: 1 day-18 to -16 °F: 0 days-16 to -14 °F: 1 day-14 to -12 °F: 2 days-12 to -10 °F: 4 days-10 to -8 °F: 3 days-8 to -6 °F: 8 days-6 to -4 °F: 0 days-4 to -2 °F: 3 days-2 to 0 °F: 4 days0 to 2 °F: 1 day2 to 4 °F: 2 days4 to 6 °F: 1 day6 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| 7.45 · P90 |e| 12.04 °F-200+20 °Fn = 30 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
-20.00-18.001
-18.00-16.000
-16.00-14.001
-14.00-12.002
-12.00-10.004
-10.00-8.003
-8.00-6.008
-6.00-4.000
-4.00-2.003
-2.00+0.004
+0.00+2.001
+2.00+4.002
+4.00+6.001
+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
2026-08248.40 -7.84
2026-0161.31 -0.39

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 30
GraphCast (IFS init)2026-01-07 → 2026-08-30 29
GraphCast (IFS init)2026-01-07 → 2026-08-30 29

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 24 +1.33 [-0.30, 3.54] no
NCEP GFS 24 +3.17 [1.58, 5.02] yes
ECMWF IFS HRES 19 +4.43 [2.42, 7.54] yes
Persistence (baseline) 24 +0.52 [-3.79, 5.33] no

Cite this page

ShortCastCheck, KLAS graphcast_ifs lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAS/model/graphcast_ifs/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), model graphcast_ifs, lead day 6. 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/6/

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