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

Los Angeles Intl · NCEP GFS · lead day 1

KLAX · gfs · lead 1

Target day = initialization date + 1 day. 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, gfs-0p25, starting 2026-08-01 — 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
tmax00Zbilinear30d29 2 QC2.06 [1.59, 2.55]2.03-0.58 [-1.69, 0.53]2.50 [1.94, 2.96]21% [7%, 37%]48%76%-0.17-0.152026-08-02 → 2026-08-30
tmax00Zbilinear90d29 2 QC2.06 [1.57, 2.56]2.03-0.58 [-1.98, 0.88]2.50 [1.89, 2.98]21% [6%, 35%]48%76%-0.17-0.152026-08-02 → 2026-08-30
tmax00Zbilinear365d29 2 QC2.06 [1.62, 2.66]2.03-0.58 [-2.17, 0.98]2.50 [1.91, 3.03]21% [6%, 36%]48%76%-0.17-0.152026-08-02 → 2026-08-30
tmax00Zbilinearall29 2 QC2.06 [1.55, 2.69]2.03-0.58 [-2.04, 0.78]2.50 [1.90, 3.05]21% [5%, 38%]48%76%-0.17-0.152026-08-02 → 2026-08-30
tmax00Znearest30d29 2 QC2.28 [1.58, 2.95]2.10-1.24 [-2.24, -0.22]2.77 [1.95, 3.37]24% [10%, 38%]52%66%-0.29-0.192026-08-02 → 2026-08-30
tmax00Znearest90d29 2 QC2.28 [1.46, 3.03]2.10-1.24 [-2.59, 0.02]2.77 [1.73, 3.41]24% [9%, 40%]52%66%-0.29-0.192026-08-02 → 2026-08-30
tmax00Znearest365d29 2 QC2.28 [1.36, 3.13]2.10-1.24 [-2.74, 0.15]2.77 [1.73, 3.49]24% [6%, 41%]52%66%-0.29-0.192026-08-02 → 2026-08-30
tmax00Znearestall29 2 QC2.28 [1.47, 3.15]2.10-1.24 [-2.61, 0.01]2.77 [1.79, 3.51]24% [8%, 43%]52%66%-0.29-0.192026-08-02 → 2026-08-30
tmax12Zbilinear30d29 2 QC1.90 [1.38, 2.41]1.74-0.88 [-1.78, 0.04]2.38 [1.67, 2.92]31% [18%, 43%]62%79%-0.08+0.022026-08-02 → 2026-08-30
tmax12Zbilinear90d29 2 QC1.90 [1.34, 2.44]1.74-0.88 [-2.04, 0.31]2.38 [1.62, 2.94]31% [17%, 43%]62%79%-0.08+0.022026-08-02 → 2026-08-30
tmax12Zbilinear365d29 2 QC1.90 [1.35, 2.50]1.74-0.88 [-2.19, 0.44]2.38 [1.62, 3.03]31% [15%, 44%]62%79%-0.08+0.022026-08-02 → 2026-08-30
tmax12Zbilinearall29 2 QC1.90 [1.35, 2.51]1.74-0.88 [-2.11, 0.30]2.38 [1.67, 3.04]31% [15%, 45%]62%79%-0.08+0.022026-08-02 → 2026-08-30
tmax12Znearest30d29 2 QC2.51 [1.89, 3.06]1.79-1.89 [-2.71, -1.07]2.95 [2.23, 3.50]10% [0%, 23%]48%69%-0.42-0.012026-08-02 → 2026-08-30
tmax12Znearest90d29 2 QC2.51 [1.68, 3.19]1.79-1.89 [-2.88, -0.95]2.95 [2.01, 3.57]10% [0%, 29%]48%69%-0.42-0.012026-08-02 → 2026-08-30
tmax12Znearest365d29 2 QC2.51 [1.64, 3.26]1.79-1.89 [-3.01, -0.82]2.95 [2.01, 3.63]10% [0%, 29%]48%69%-0.42-0.012026-08-02 → 2026-08-30
tmax12Znearestall29 2 QC2.51 [1.63, 3.22]1.79-1.89 [-2.97, -0.88]2.95 [2.02, 3.64]10% [0%, 33%]48%69%-0.42-0.012026-08-02 → 2026-08-30
tmin00Zbilinear30d29 2 QC3.48 [2.59, 4.33]1.45+3.34 [2.26, 4.33]3.80 [2.94, 4.52]3% [0%, 10%]24%38%-2.88-0.562026-08-02 → 2026-08-30
tmin00Zbilinear90d29 2 QC3.48 [2.56, 4.42]1.45+3.34 [2.22, 4.42]3.80 [2.87, 4.61]3% [0%, 10%]24%38%-2.88-0.562026-08-02 → 2026-08-30
tmin00Zbilinear365d29 2 QC3.48 [2.44, 4.48]1.45+3.34 [2.09, 4.48]3.80 [2.74, 4.64]3% [0%, 11%]24%38%-2.88-0.562026-08-02 → 2026-08-30
tmin00Zbilinearall29 2 QC3.48 [2.55, 4.55]1.45+3.34 [2.19, 4.55]3.80 [2.85, 4.70]3% [0%, 10%]24%38%-2.88-0.562026-08-02 → 2026-08-30
tmin00Znearest30d29 2 QC2.28 [1.64, 3.01]1.54+1.92 [0.85, 2.99]2.72 [2.04, 3.37]24% [10%, 38%]41%69%-1.54-0.662026-08-02 → 2026-08-30
tmin00Znearest90d29 2 QC2.28 [1.50, 3.12]1.54+1.92 [0.82, 3.05]2.72 [1.83, 3.43]24% [8%, 43%]41%69%-1.54-0.662026-08-02 → 2026-08-30
tmin00Znearest365d29 2 QC2.28 [1.43, 3.16]1.54+1.92 [0.67, 3.14]2.72 [1.71, 3.48]24% [7%, 45%]41%69%-1.54-0.662026-08-02 → 2026-08-30
tmin00Znearestall29 2 QC2.28 [1.51, 3.20]1.54+1.92 [0.73, 3.20]2.72 [1.83, 3.49]24% [7%, 45%]41%69%-1.54-0.662026-08-02 → 2026-08-30
tmin12Zbilinear30d29 2 QC2.98 [2.15, 3.79]1.26+2.86 [1.84, 3.77]3.25 [2.40, 3.97]3% [0%, 10%]31%48%-2.32-0.352026-08-02 → 2026-08-30
tmin12Zbilinear90d29 2 QC2.98 [2.13, 3.89]1.26+2.86 [1.77, 3.89]3.25 [2.36, 4.03]3% [0%, 11%]31%48%-2.32-0.352026-08-02 → 2026-08-30
tmin12Zbilinear365d29 2 QC2.98 [2.00, 3.98]1.26+2.86 [1.66, 3.98]3.25 [2.24, 4.09]3% [0%, 11%]31%48%-2.32-0.352026-08-02 → 2026-08-30
tmin12Zbilinearall29 2 QC2.98 [2.08, 4.03]1.26+2.86 [1.78, 4.03]3.25 [2.27, 4.14]3% [0%, 10%]31%48%-2.32-0.352026-08-02 → 2026-08-30
tmin12Znearest30d29 2 QC1.81 [1.15, 2.56]1.33+1.50 [0.52, 2.49]2.21 [1.47, 2.83]31% [10%, 52%]52%86%-1.02-0.432026-08-02 → 2026-08-30
tmin12Znearest90d29 2 QC1.81 [1.06, 2.57]1.33+1.50 [0.46, 2.52]2.21 [1.40, 2.85]31% [9%, 54%]52%86%-1.02-0.432026-08-02 → 2026-08-30
tmin12Znearest365d29 2 QC1.81 [1.06, 2.66]1.33+1.50 [0.33, 2.64]2.21 [1.38, 2.90]31% [8%, 55%]52%86%-1.02-0.432026-08-02 → 2026-08-30
tmin12Znearestall29 2 QC1.81 [1.05, 2.73]1.33+1.50 [0.44, 2.73]2.21 [1.34, 2.96]31% [7%, 55%]52%86%-1.02-0.432026-08-02 → 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 NCEP GFS at KLAX, lead day 1, 00Z bilinear tmax+10+50-5-102026-08-02: +2.79 °F2026-08-03: +2.21 °F2026-08-04: +2.45 °F2026-08-05: +1.08 °F2026-08-06: -0.73 °F2026-08-07: -1.08 °F2026-08-08: +2.1 °F2026-08-09: +1.04 °F2026-08-10: +0.16 °F2026-08-11: -2.27 °F2026-08-12: -3.13 °F2026-08-13: -4.2 °F2026-08-14: -3.98 °F2026-08-15: -1.21 °F2026-08-16: +1.05 °F2026-08-17: +3.06 °F2026-08-18: -1.4 °F2026-08-19: +0.45 °F2026-08-20: +4.25 °F2026-08-21: -2.75 °F2026-08-22: +0.39 °F2026-08-23: -1.3 °F2026-08-24: -0.11 °F2026-08-25: +0.4 °F2026-08-26: -2.9 °F2026-08-27: -5.96 °F2026-08-28: -1.39 °F2026-08-29: -3.24 °F2026-08-30: -2.71 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.71
2026-08-29-3.24
2026-08-28-1.39
2026-08-27-5.96
2026-08-26-2.90
2026-08-25+0.40
2026-08-24-0.11
2026-08-23-1.30
2026-08-22+0.39
2026-08-21-2.75
2026-08-20+4.25
2026-08-19+0.45
2026-08-18-1.40
2026-08-17+3.06
2026-08-16+1.05
2026-08-15-1.21
2026-08-14-3.98
2026-08-13-4.20
2026-08-12-3.13
2026-08-11-2.27
2026-08-10+0.16
2026-08-09+1.04
2026-08-08+2.10
2026-08-07-1.08
2026-08-06-0.73
2026-08-05+1.08
2026-08-04+2.45
2026-08-03+2.21
2026-08-02+2.79

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KLAX, lead day 1-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 1 day-5 to -4 °F: 1 day-4 to -3 °F: 3 days-3 to -2 °F: 4 days-2 to -1 °F: 5 days-1 to 0 °F: 2 days0 to 1 °F: 4 days1 to 2 °F: 3 days2 to 3 °F: 4 days3 to 4 °F: 1 day4 to 5 °F: 1 day5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.1 · P90 |e| 4.03 °F-100+10 °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
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.001
-5.00-4.001
-4.00-3.003
-3.00-2.004
-2.00-1.005
-1.00+0.002
+0.00+1.004
+1.00+2.003
+2.00+3.004
+3.00+4.001
+4.00+5.001
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08292.06 -0.58

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means NCEP GFS has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 29 +0.49 [-0.07, 1.10] no
Aurora (GFS init) 1 -3.23 [-3.23, -3.23] yes
Aurora (IFS init) 2 -2.93 [-3.25, -2.61] yes
FourCastNet v2 (GFS init) 1 -0.04 [-0.04, -0.04] yes
FourCastNet v2 (IFS init) 2 -0.11 [-0.12, -0.09] yes
GraphCast (GFS init) 1 -2.54 [-2.54, -2.54] yes
GraphCast (IFS init) 27 -1.65 [-2.52, -1.00] yes
ECMWF IFS HRES 22 -0.21 [-0.65, 0.58] no
Pangu-Weather (GFS init) 1 +0.32 [0.32, 0.32] yes
Pangu-Weather (IFS init) 2 -0.30 [-0.56, -0.04] yes
Persistence (baseline) 29 +0.30 [-0.55, 1.06] no

Cite this page

ShortCastCheck, KLAX gfs lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KLAX (Los Angeles Intl), model gfs, lead day 1. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KLAX/model/gfs/lead/1/

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