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

Las Vegas Harry Reid · GraphCast (IFS init) · lead day 7

KLAS · graphcast_ifs · lead 7

Target day = initialization date + 7 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
tmax00Zbilinear30d23 2 QC8.91 [6.28, 11.39]4.41-8.66 [-11.38, -5.89]10.39 [7.66, 12.61]0% [0%, 0%]9%22%-0.06+0.472026-08-08 → 2026-08-30
tmax00Zbilinear90d23 2 QC8.91 [5.79, 11.74]4.41-8.66 [-11.74, -5.38]10.39 [7.27, 12.90]0% [0%, 0%]9%22%-0.06+0.472026-08-08 → 2026-08-30
tmax00Zbilinear365d29 2 QC7.33 [3.19, 10.38]5.10-6.99 [-10.35, -2.81]9.29 [5.29, 11.83]10% [0%, 32%]24%34%+0.03+0.322026-01-08 → 2026-08-30
tmax00Zbilinearall29 2 QC7.33 [2.68, 10.91]5.10-6.99 [-10.91, -2.28]9.29 [4.59, 12.26]10% [0%, 36%]24%34%+0.03+0.322026-01-08 → 2026-08-30
tmax00Znearest30d23 2 QC9.97 [7.37, 12.53]4.33-9.82 [-12.53, -7.08]11.33 [8.63, 13.55]0% [0%, 0%]4%13%-0.18+0.482026-08-08 → 2026-08-30
tmax00Znearest90d23 2 QC9.97 [6.91, 12.81]4.33-9.82 [-12.81, -6.65]11.33 [8.19, 13.80]0% [0%, 0%]4%13%-0.18+0.482026-08-08 → 2026-08-30
tmax00Znearest365d29 2 QC8.29 [4.13, 11.48]5.13-8.10 [-11.47, -3.86]10.14 [5.81, 12.76]0% [0%, 0%]21%28%-0.09+0.322026-01-08 → 2026-08-30
tmax00Znearestall29 2 QC8.29 [3.57, 12.01]5.13-8.10 [-12.01, -3.31]10.14 [5.27, 13.19]0% [0%, 0%]21%28%-0.09+0.322026-01-08 → 2026-08-30
tmax12Zbilinear30d23 2 QC8.95 [6.29, 11.10]4.05-8.65 [-10.99, -6.06]10.01 [7.67, 11.64]4% [0%, 15%]13%17%-0.06+0.512026-08-08 → 2026-08-30
tmax12Zbilinear90d23 2 QC8.95 [5.53, 11.23]4.05-8.65 [-11.22, -5.29]10.01 [6.60, 11.73]4% [0%, 18%]13%17%-0.06+0.512026-08-08 → 2026-08-30
tmax12Zbilinear365d28 2 QC7.56 [3.23, 10.49]4.88-7.13 [-10.40, -2.67]9.10 [4.44, 11.16]7% [0%, 20%]25%32%-0.00+0.342026-01-08 → 2026-08-30
tmax12Zbilinearall28 2 QC7.56 [2.30, 10.55]4.88-7.13 [-10.38, -1.81]9.10 [3.79, 11.25]7% [0%, 20%]25%32%-0.00+0.342026-01-08 → 2026-08-30
tmax12Znearest30d23 2 QC9.90 [7.36, 12.11]4.00-9.80 [-12.08, -7.27]10.98 [8.62, 12.61]9% [0%, 23%]9%13%-0.17+0.522026-08-08 → 2026-08-30
tmax12Znearest90d23 2 QC9.90 [6.62, 12.36]4.00-9.80 [-12.33, -6.58]10.98 [7.63, 12.75]9% [0%, 23%]9%13%-0.17+0.522026-08-08 → 2026-08-30
tmax12Znearest365d28 2 QC8.44 [4.11, 11.49]4.89-8.23 [-11.45, -3.77]9.98 [5.49, 12.11]7% [0%, 20%]21%29%-0.12+0.342026-01-08 → 2026-08-30
tmax12Znearestall28 2 QC8.44 [3.39, 11.49]4.89-8.23 [-11.43, -2.91]9.98 [4.51, 12.23]7% [0%, 19%]21%29%-0.12+0.342026-01-08 → 2026-08-30
tmin00Zbilinear30d23 2 QC5.60 [4.23, 6.97]3.64-4.35 [-6.91, -1.17]6.26 [4.92, 7.40]9% [0%, 23%]9%17%+0.28+0.522026-08-08 → 2026-08-30
tmin00Zbilinear90d23 2 QC5.60 [4.15, 7.21]3.64-4.35 [-7.21, -1.13]6.26 [4.89, 7.61]9% [0%, 25%]9%17%+0.28+0.522026-08-08 → 2026-08-30
tmin00Zbilinear365d29 2 QC5.46 [4.19, 6.77]4.87-2.43 [-6.21, 2.02]6.09 [4.84, 7.21]7% [0%, 21%]10%21%+0.27+0.332026-01-08 → 2026-08-30
tmin00Zbilinearall29 2 QC5.46 [4.15, 6.90]4.87-2.43 [-6.52, 2.63]6.09 [4.82, 7.35]7% [0%, 19%]10%21%+0.27+0.332026-01-08 → 2026-08-30
tmin00Znearest30d23 2 QC6.41 [4.53, 8.15]3.69-5.53 [-8.13, -2.34]7.15 [5.40, 8.51]4% [0%, 12%]13%17%+0.17+0.522026-08-08 → 2026-08-30
tmin00Znearest90d23 2 QC6.41 [4.36, 8.42]3.69-5.53 [-8.42, -2.28]7.15 [5.23, 8.72]4% [0%, 13%]13%17%+0.17+0.522026-08-08 → 2026-08-30
tmin00Znearest365d29 2 QC6.02 [4.31, 7.78]5.10-3.44 [-7.44, 1.29]6.79 [5.11, 8.22]7% [0%, 17%]17%21%+0.20+0.302026-01-08 → 2026-08-30
tmin00Znearestall29 2 QC6.02 [4.19, 7.97]5.10-3.44 [-7.64, 1.98]6.79 [5.05, 8.37]7% [0%, 18%]17%21%+0.20+0.302026-01-08 → 2026-08-30
tmin12Zbilinear30d23 2 QC5.70 [4.51, 6.85]3.58-4.28 [-6.83, -1.01]6.28 [5.04, 7.30]4% [0%, 12%]4%17%+0.26+0.532026-08-08 → 2026-08-30
tmin12Zbilinear90d23 2 QC5.70 [4.47, 7.02]3.58-4.28 [-7.02, -0.98]6.28 [4.97, 7.41]4% [0%, 12%]4%17%+0.26+0.532026-08-08 → 2026-08-30
tmin12Zbilinear365d28 2 QC5.55 [4.40, 6.68]4.78-2.64 [-6.24, 1.69]6.17 [5.02, 7.10]4% [0%, 11%]7%21%+0.29+0.362026-01-08 → 2026-08-30
tmin12Zbilinearall28 2 QC5.55 [4.32, 6.87]4.78-2.64 [-6.54, 2.45]6.17 [4.93, 7.30]4% [0%, 10%]7%21%+0.29+0.362026-01-08 → 2026-08-30
tmin12Znearest30d23 2 QC6.47 [4.83, 7.97]3.64-5.41 [-7.97, -2.17]7.14 [5.61, 8.38]0% [0%, 0%]13%13%+0.16+0.522026-08-08 → 2026-08-30
tmin12Znearest90d23 2 QC6.47 [4.78, 8.17]3.64-5.41 [-8.17, -2.09]7.14 [5.47, 8.51]0% [0%, 0%]13%13%+0.16+0.522026-08-08 → 2026-08-30
tmin12Znearest365d28 2 QC6.10 [4.50, 7.68]4.96-3.66 [-7.38, 0.89]6.86 [5.28, 8.10]4% [0%, 13%]18%18%+0.22+0.332026-01-08 → 2026-08-30
tmin12Znearestall28 2 QC6.10 [4.37, 7.88]4.96-3.66 [-7.68, 1.65]6.86 [5.18, 8.31]4% [0%, 14%]18%18%+0.22+0.332026-01-08 → 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 7, 00Z bilinear tmax+25+12.50-12.5-252026-08-08: -17.53 °F2026-08-09: -8.59 °F2026-08-10: -8.94 °F2026-08-11: -9.21 °F2026-08-12: -14.1 °F2026-08-13: -2.72 °F2026-08-14: -2.5 °F2026-08-15: +2.95 °F2026-08-16: -6.39 °F2026-08-17: -8.56 °F2026-08-18: -13.71 °F2026-08-19: -12.55 °F2026-08-20: -7.61 °F2026-08-21: -4.58 °F2026-08-22: -8.1 °F2026-08-23: -22.26 °F2026-08-24: -15.55 °F2026-08-25: -13.18 °F2026-08-26: -8.7 °F2026-08-27: -10.17 °F2026-08-28: -4.52 °F2026-08-29: -1.34 °F2026-08-30: -1.28 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.28
2026-08-29-1.34
2026-08-28-4.52
2026-08-27-10.17
2026-08-26-8.70
2026-08-25-13.18
2026-08-24-15.55
2026-08-23-22.26
2026-08-22-8.10
2026-08-21-4.58
2026-08-20-7.61
2026-08-19-12.55
2026-08-18-13.71
2026-08-17-8.56
2026-08-16-6.39
2026-08-15+2.95
2026-08-14-2.50
2026-08-13-2.72
2026-08-12-14.10
2026-08-11-9.21
2026-08-10-8.94
2026-08-09-8.59
2026-08-08-17.53

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KLAS, lead day 7-25 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: 1 day-15 to -12.5 °F: 4 days-12.5 to -10 °F: 1 day-10 to -7.5 °F: 7 days-7.5 to -5 °F: 1 day-5 to -2.5 °F: 4 days-2.5 to 0 °F: 7 days0 to 2.5 °F: 1 day2.5 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| 7.61 · P90 |e| 14.39 °F-250+25 °Fn = 29 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
-17.50-15.001
-15.00-12.504
-12.50-10.001
-10.00-7.507
-7.50-5.001
-5.00-2.504
-2.50+0.007
+0.00+2.501
+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
2026-08238.91 -8.66
2026-0161.27 -0.60

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-08 → 2026-08-30 29
GraphCast (IFS init)2026-01-08 → 2026-08-30 29
GraphCast (IFS init)2026-01-08 → 2026-08-30 28
GraphCast (IFS init)2026-01-08 → 2026-08-30 28

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 23 +1.88 [0.02, 4.27] yes
NCEP GFS 23 +2.16 [-0.32, 5.95] no
ECMWF IFS HRES 18 +4.29 [1.01, 7.98] yes
Persistence (baseline) 23 +0.48 [-4.47, 6.20] no

Cite this page

ShortCastCheck, KLAS graphcast_ifs lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAS/model/graphcast_ifs/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAS (Las Vegas Harry Reid), model graphcast_ifs, lead day 7. 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/7/

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