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

KLAS — Las Vegas Harry Reid

36.0719, -115.1634 · 664 m· standard offset UTC-8 h · truth product CLILAS

These pages are always bilinear interpolation, the headline method. The nearest-node variant, and every other window/initialization/interpolation/variable combination, is published on each permanent link below — follow any number.

Daily maximum temperature — MAE °F

the last 90 days, 00Z, bilinear. MAE with the bias and n underneath; every cell links to its permanent page. The sparkline shows the same model across lead days 1–9 on a scale shared within this table.
Modeld0d1d2d3d4d5d6d7d8d9lead 1–9
ECMWF AIFS Singleaifs_single 5.08-4.82 · n=30 4.47-4.34 · n=29 4.95-4.82 · n=28 5.07-5.02 · n=27 5.79-5.28 · n=26 6.05-5.34 · n=25 7.07-6.53 · n=24 7.03-6.78 · n=23 8.25-8.08 · n=22 ECMWF AIFS Single MAE by lead day 1 to 9, tmax
Aurora (GFS init)aurora_gfs 5.38-5.38 · n=2 5.12-5.12 · n=1 Aurora (GFS init) MAE by lead day 1 to 9, tmax
Aurora (IFS init)aurora_ifs 3.97-3.97 · n=3 3.98-3.98 · n=2 3.92-3.92 · n=1 Aurora (IFS init) MAE by lead day 1 to 9, tmax
FourCastNet v2 (GFS init)fourcastnet_gfs 5.26-5.26 · n=2 4.45-4.45 · n=1 FourCastNet v2 (GFS init) MAE by lead day 1 to 9, tmax
FourCastNet v2 (IFS init)fourcastnet_ifs 5.93-5.93 · n=3 6.07-6.07 · n=2 5.92-5.92 · n=1 FourCastNet v2 (IFS init) MAE by lead day 1 to 9, tmax
NCEP GFSgfs 5.08-4.52 · n=30 5.14-4.42 · n=29 4.60-3.75 · n=28 4.69-3.69 · n=27 4.46-2.80 · n=26 4.72-3.16 · n=25 5.23-3.15 · n=24 6.75-3.40 · n=23 5.99-3.48 · n=22 NCEP GFS MAE by lead day 1 to 9, tmax
GraphCast (GFS init)graphcast_gfs 7.94-7.94 · n=2 7.64-7.64 · n=1 GraphCast (GFS init) MAE by lead day 1 to 9, tmax
GraphCast (IFS init)graphcast_ifs 5.17-4.94 · n=28 4.90-4.73 · n=27 5.63-5.31 · n=26 5.94-5.71 · n=25 7.23-6.58 · n=25 7.11-6.81 · n=25 8.40-7.84 · n=24 8.91-8.66 · n=23 10.46-9.90 · n=22 GraphCast (IFS init) MAE by lead day 1 to 9, tmax
ECMWF IFS HRESifs_hres 3.89-3.66 · n=25 3.83-2.58 · n=22 3.14-2.37 · n=23 3.46-1.89 · n=22 3.31-2.52 · n=20 3.33-3.02 · n=18 3.92-2.74 · n=19 4.68-3.37 · n=18 6.30-4.38 · n=17 ECMWF IFS HRES MAE by lead day 1 to 9, tmax
Pangu-Weather (GFS init)pangu_gfs 5.16-5.16 · n=2 4.89-4.89 · n=1 Pangu-Weather (GFS init) MAE by lead day 1 to 9, tmax
Pangu-Weather (IFS init)pangu_ifs 5.32-5.32 · n=3 5.80-5.80 · n=2 5.51-5.51 · n=1 Pangu-Weather (IFS init) MAE by lead day 1 to 9, tmax
Persistence (baseline)persistence 2.94-0.01 · n=90 4.07-0.13 · n=90 4.94-0.34 · n=90 5.52-0.70 · n=90 6.22-1.00 · n=90 6.80-1.29 · n=90 6.83-1.48 · n=90 6.76-1.64 · n=90 7.14-1.81 · n=90 Persistence (baseline) MAE by lead day 1 to 9, tmax

Up to 2 of the scored days in this table carry a QC flag on the observation (a CLI value that disagreed with the hourly observations, or a fallback source). They are kept in the scores and counted here rather than dropped — see methodology.

+ 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 minimum temperature — MAE °F

the last 90 days, 00Z, bilinear. MAE with the bias and n underneath; every cell links to its permanent page. The sparkline shows the same model across lead days 1–9 on a scale shared within this table.
Modeld0d1d2d3d4d5d6d7d8d9lead 1–9
ECMWF AIFS Singleaifs_single 4.99-4.92 · n=30 5.34-5.29 · n=29 5.29-5.01 · n=28 5.11-4.94 · n=27 5.21-4.70 · n=26 5.36-4.85 · n=25 5.31-5.10 · n=24 6.17-6.13 · n=23 6.71-6.37 · n=22 ECMWF AIFS Single MAE by lead day 1 to 9, tmin
Aurora (GFS init)aurora_gfs 6.88-6.88 · n=2 8.05-8.05 · n=1 Aurora (GFS init) MAE by lead day 1 to 9, tmin
Aurora (IFS init)aurora_ifs 4.29-4.29 · n=3 5.96-5.96 · n=2 7.33-7.33 · n=1 Aurora (IFS init) MAE by lead day 1 to 9, tmin
FourCastNet v2 (GFS init)fourcastnet_gfs 6.12-6.12 · n=2 6.18-6.18 · n=1 FourCastNet v2 (GFS init) MAE by lead day 1 to 9, tmin
FourCastNet v2 (IFS init)fourcastnet_ifs 4.94-4.94 · n=3 6.12-6.12 · n=2 7.64-7.64 · n=1 FourCastNet v2 (IFS init) MAE by lead day 1 to 9, tmin
NCEP GFSgfs 3.19-1.22 · n=30 3.46-1.39 · n=29 3.71-0.94 · n=28 3.39-0.12 · n=27 3.59-0.20 · n=26 3.37+0.44 · n=25 3.81+0.15 · n=24 4.54+0.22 · n=23 4.93-0.42 · n=22 NCEP GFS MAE by lead day 1 to 9, tmin
GraphCast (GFS init)graphcast_gfs 6.58-6.58 · n=2 9.42-9.42 · n=1 GraphCast (GFS init) MAE by lead day 1 to 9, tmin
GraphCast (IFS init)graphcast_ifs 2.40-1.83 · n=28 3.11-2.66 · n=27 3.27-2.85 · n=26 3.34-2.85 · n=25 3.95-3.11 · n=25 4.65-3.65 · n=25 4.82-3.92 · n=24 5.60-4.35 · n=23 6.04-4.88 · n=22 GraphCast (IFS init) MAE by lead day 1 to 9, tmin
ECMWF IFS HRESifs_hres 3.09-2.61 · n=25 3.61-2.76 · n=22 3.82-3.06 · n=23 4.25-2.54 · n=22 4.58-3.15 · n=20 4.56-2.50 · n=18 5.00-2.76 · n=19 5.43-3.68 · n=18 5.68-4.43 · n=17 ECMWF IFS HRES MAE by lead day 1 to 9, tmin
Pangu-Weather (GFS init)pangu_gfs 7.76-7.76 · n=2 6.67-6.67 · n=1 Pangu-Weather (GFS init) MAE by lead day 1 to 9, tmin
Pangu-Weather (IFS init)pangu_ifs 4.85-4.85 · n=3 6.21-6.21 · n=2 7.28-7.28 · n=1 Pangu-Weather (IFS init) MAE by lead day 1 to 9, tmin
Persistence (baseline)persistence 2.40-0.13 · n=90 3.82-0.31 · n=90 4.61-0.59 · n=90 5.34-0.92 · n=90 5.92-1.26 · n=90 6.34-1.54 · n=90 6.34-1.83 · n=90 6.52-2.03 · n=90 6.89-2.20 · n=90 Persistence (baseline) MAE by lead day 1 to 9, tmin

Up to 2 of the scored days in this table carry a QC flag on the observation (a CLI value that disagreed with the hourly observations, or a fallback source). They are kept in the scores and counted here rather than dropped — see methodology.

Month by month

MAE °F at lead day 1, 00Z, bilinear, daily maximum — the seasonal slice behind the window averages. A model that is excellent in one season and poor in another shows up here and nowhere else.

Monthaifs_singleaurora_gfsaurora_ifsfourcastnet_gfsfourcastnet_ifsgfsgraphcast_gfsgraphcast_ifsifs_hrespangu_gfspangu_ifs
2026-08 4.47-4.34 · n=295.12-5.12 · n=13.98-3.98 · n=24.45-4.45 · n=16.07-6.07 · n=25.14-4.42 · n=297.64-7.64 · n=14.90-4.73 · n=273.83-2.58 · n=224.89-4.89 · n=15.80-5.80 · n=2
2026-01 4.80-4.80 · n=6

Model availability at this station

ModelPeriod Scored daysCoverage
ECMWF AIFS Single 2026-08-02 → 2026-08-3029
Aurora (GFS init) 2026-08-30 → 2026-08-301
Aurora (IFS init) 2026-08-29 → 2026-08-302
FourCastNet v2 (GFS init) 2026-08-30 → 2026-08-301
FourCastNet v2 (IFS init) 2026-08-29 → 2026-08-302
NCEP GFS 2026-08-02 → 2026-08-3029
GraphCast (GFS init) 2026-08-30 → 2026-08-301
GraphCast (IFS init) 2026-01-02 → 2026-08-3033
ECMWF IFS HRES 2026-08-02 → 2026-08-3022
Pangu-Weather (GFS init) 2026-08-30 → 2026-08-301
Pangu-Weather (IFS init) 2026-08-29 → 2026-08-302
Persistence (baseline) 2024-01-02 → 2026-08-30972

Observed truth — last 30 days

Climatological dayTmax °F Tmin °FSourceFlag
2026-08-3010086OBSobs_fallback
2026-08-2910587CLIobs_diff_gt2f
2026-08-2810790CLI
2026-08-2711192CLI
2026-08-2611087CLI
2026-08-2510885CLI
2026-08-2410890CLI
2026-08-2311088CLI
2026-08-2210988CLI
2026-08-2110887CLI
2026-08-2010989CLI
2026-08-1911086CLI
2026-08-1810986CLI
2026-08-1710883CLI
2026-08-1610276CLI
2026-08-158971CLI
2026-08-149772CLI
2026-08-139175CLI
2026-08-1210179CLI
2026-08-1110188CLI
2026-08-1010490CLI
2026-08-0911090CLI
2026-08-0811390CLI
2026-08-0710990CLI
2026-08-0610889CLI
2026-08-0511391CLI
2026-08-0411291CLI
2026-08-0311391CLI
2026-08-0211392CLI
2026-08-0111587CLI

All scores as JSON scores_latest.csv daily_errors.csv.gz data & licences