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

San Diego Lindbergh · NCEP GFS · lead day 3

KSAN · gfs · lead 3

Target day = initialization date + 3 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, 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, 1 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
tmax00Zbilinear30d27 1 QC2.97 [2.19, 3.86]1.53-2.91 [-3.85, -2.07]3.67 [2.54, 4.89]19% [7%, 33%]33%56%-0.38+0.262026-08-04 → 2026-08-30
tmax00Zbilinear90d27 1 QC2.97 [2.08, 3.94]1.53-2.91 [-3.91, -1.93]3.67 [2.43, 4.90]19% [5%, 32%]33%56%-0.38+0.262026-08-04 → 2026-08-30
tmax00Zbilinear365d27 1 QC2.97 [2.06, 4.12]1.53-2.91 [-4.11, -1.90]3.67 [2.42, 5.18]19% [5%, 33%]33%56%-0.38+0.262026-08-04 → 2026-08-30
tmax00Zbilinearall27 1 QC2.97 [2.13, 4.04]1.53-2.91 [-4.04, -1.95]3.67 [2.43, 5.03]19% [5%, 33%]33%56%-0.38+0.262026-08-04 → 2026-08-30
tmax00Znearest30d27 1 QC5.36 [4.48, 6.53]1.59-5.36 [-6.53, -4.48]5.86 [4.67, 7.28]0% [0%, 0%]4%7%-1.49+0.232026-08-04 → 2026-08-30
tmax00Znearest90d27 1 QC5.36 [4.37, 6.58]1.59-5.36 [-6.58, -4.37]5.86 [4.58, 7.35]0% [0%, 0%]4%7%-1.49+0.232026-08-04 → 2026-08-30
tmax00Znearest365d27 1 QC5.36 [4.32, 6.79]1.59-5.36 [-6.79, -4.32]5.86 [4.51, 7.60]0% [0%, 0%]4%7%-1.49+0.232026-08-04 → 2026-08-30
tmax00Znearestall27 1 QC5.36 [4.32, 6.73]1.59-5.36 [-6.73, -4.32]5.86 [4.49, 7.47]0% [0%, 0%]4%7%-1.49+0.232026-08-04 → 2026-08-30
tmax12Zbilinear30d27 1 QC2.98 [2.27, 3.71]1.39-2.98 [-3.70, -2.27]3.60 [2.61, 4.56]15% [7%, 26%]30%67%-0.39+0.332026-08-04 → 2026-08-30
tmax12Zbilinear90d27 1 QC2.98 [2.15, 3.76]1.39-2.98 [-3.76, -2.15]3.60 [2.48, 4.66]15% [6%, 29%]30%67%-0.39+0.332026-08-04 → 2026-08-30
tmax12Zbilinear365d27 1 QC2.98 [2.07, 3.93]1.39-2.98 [-3.93, -2.06]3.60 [2.41, 4.87]15% [5%, 29%]30%67%-0.39+0.332026-08-04 → 2026-08-30
tmax12Zbilinearall27 1 QC2.98 [2.16, 3.87]1.39-2.98 [-3.87, -2.14]3.60 [2.52, 4.78]15% [4%, 30%]30%67%-0.39+0.332026-08-04 → 2026-08-30
tmax12Znearest30d27 1 QC5.40 [4.65, 6.30]1.34-5.40 [-6.30, -4.65]5.81 [4.77, 6.98]0% [0%, 0%]0%7%-1.51+0.352026-08-04 → 2026-08-30
tmax12Znearest90d27 1 QC5.40 [4.51, 6.39]1.34-5.40 [-6.39, -4.51]5.81 [4.65, 7.08]0% [0%, 0%]0%7%-1.51+0.352026-08-04 → 2026-08-30
tmax12Znearest365d27 1 QC5.40 [4.46, 6.58]1.34-5.40 [-6.58, -4.46]5.81 [4.60, 7.24]0% [0%, 0%]0%7%-1.51+0.352026-08-04 → 2026-08-30
tmax12Znearestall27 1 QC5.40 [4.45, 6.51]1.34-5.40 [-6.51, -4.45]5.81 [4.58, 7.16]0% [0%, 0%]0%7%-1.51+0.352026-08-04 → 2026-08-30
tmin00Zbilinear30d27 1 QC2.63 [2.06, 3.19]1.22+2.40 [1.51, 3.19]2.88 [2.38, 3.34]11% [0%, 23%]26%59%-1.54-0.162026-08-04 → 2026-08-30
tmin00Zbilinear90d27 1 QC2.63 [2.02, 3.26]1.22+2.40 [1.46, 3.25]2.88 [2.34, 3.38]11% [0%, 25%]26%59%-1.54-0.162026-08-04 → 2026-08-30
tmin00Zbilinear365d27 1 QC2.63 [1.89, 3.28]1.22+2.40 [1.35, 3.28]2.88 [2.25, 3.39]11% [0%, 27%]26%59%-1.54-0.162026-08-04 → 2026-08-30
tmin00Zbilinearall27 1 QC2.63 [1.93, 3.36]1.22+2.40 [1.36, 3.36]2.88 [2.28, 3.44]11% [0%, 28%]26%59%-1.54-0.162026-08-04 → 2026-08-30
tmin00Znearest30d27 1 QC1.92 [1.54, 2.27]1.15+1.61 [0.90, 2.23]2.15 [1.83, 2.41]26% [11%, 41%]41%93%-0.85-0.102026-08-04 → 2026-08-30
tmin00Znearest90d27 1 QC1.92 [1.47, 2.35]1.15+1.61 [0.87, 2.31]2.15 [1.75, 2.47]26% [9%, 43%]41%93%-0.85-0.102026-08-04 → 2026-08-30
tmin00Znearest365d27 1 QC1.92 [1.41, 2.37]1.15+1.61 [0.80, 2.36]2.15 [1.68, 2.48]26% [7%, 43%]41%93%-0.85-0.102026-08-04 → 2026-08-30
tmin00Znearestall27 1 QC1.92 [1.36, 2.34]1.15+1.61 [0.77, 2.33]2.15 [1.66, 2.46]26% [7%, 43%]41%93%-0.85-0.102026-08-04 → 2026-08-30
tmin12Zbilinear30d27 1 QC2.47 [1.79, 3.10]1.22+2.28 [1.38, 3.07]2.75 [2.12, 3.25]11% [0%, 23%]33%63%-1.38-0.162026-08-04 → 2026-08-30
tmin12Zbilinear90d27 1 QC2.47 [1.74, 3.17]1.22+2.28 [1.31, 3.13]2.75 [2.10, 3.31]11% [0%, 25%]33%63%-1.38-0.162026-08-04 → 2026-08-30
tmin12Zbilinear365d27 1 QC2.47 [1.65, 3.21]1.22+2.28 [1.19, 3.19]2.75 [1.98, 3.35]11% [0%, 27%]33%63%-1.38-0.162026-08-04 → 2026-08-30
tmin12Zbilinearall27 1 QC2.47 [1.64, 3.23]1.22+2.28 [1.21, 3.22]2.75 [1.98, 3.37]11% [0%, 28%]33%63%-1.38-0.162026-08-04 → 2026-08-30
tmin12Znearest30d27 1 QC1.83 [1.39, 2.21]1.11+1.53 [0.81, 2.13]2.05 [1.65, 2.37]22% [4%, 42%]56%85%-0.76-0.062026-08-04 → 2026-08-30
tmin12Znearest90d27 1 QC1.83 [1.40, 2.29]1.11+1.53 [0.76, 2.26]2.05 [1.65, 2.40]22% [0%, 41%]56%85%-0.76-0.062026-08-04 → 2026-08-30
tmin12Znearest365d27 1 QC1.83 [1.34, 2.32]1.11+1.53 [0.69, 2.28]2.05 [1.58, 2.41]22% [0%, 42%]56%85%-0.76-0.062026-08-04 → 2026-08-30
tmin12Znearestall27 1 QC1.83 [1.31, 2.32]1.11+1.53 [0.66, 2.23]2.05 [1.56, 2.45]22% [0%, 43%]56%85%-0.76-0.062026-08-04 → 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 KSAN, lead day 3, 00Z bilinear tmax+20+100-10-202026-08-04: +0.39 °F2026-08-05: -2.2 °F2026-08-06: -3.05 °F2026-08-07: -2.86 °F2026-08-08: -1.65 °F2026-08-09: -3.4 °F2026-08-10: -3.82 °F2026-08-11: -2.04 °F2026-08-12: -2.89 °F2026-08-13: -3.18 °F2026-08-14: -4.42 °F2026-08-15: -3.83 °F2026-08-16: -1.79 °F2026-08-17: -1.57 °F2026-08-18: -0.59 °F2026-08-19: +0.43 °F2026-08-20: -2.34 °F2026-08-21: -3.22 °F2026-08-22: -1.61 °F2026-08-23: -6.71 °F2026-08-24: -0.94 °F2026-08-25: -3.67 °F2026-08-26: -10.91 °F2026-08-27: -3.45 °F2026-08-28: -0.94 °F2026-08-29: -5.84 °F2026-08-30: -2.39 °F2026-08-042026-08-30°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 (27 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.39
2026-08-29-5.84
2026-08-28-0.94
2026-08-27-3.45
2026-08-26-10.91
2026-08-25-3.67
2026-08-24-0.94
2026-08-23-6.71
2026-08-22-1.61
2026-08-21-3.22
2026-08-20-2.34
2026-08-19+0.43
2026-08-18-0.59
2026-08-17-1.57
2026-08-16-1.79
2026-08-15-3.83
2026-08-14-4.42
2026-08-13-3.18
2026-08-12-2.89
2026-08-11-2.04
2026-08-10-3.82
2026-08-09-3.40
2026-08-08-1.65
2026-08-07-2.86
2026-08-06-3.05
2026-08-05-2.20
2026-08-04+0.39

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAN, lead day 3-20 to -18 °F: 0 days-18 to -16 °F: 0 days-16 to -14 °F: 0 days-14 to -12 °F: 0 days-12 to -10 °F: 1 day-10 to -8 °F: 0 days-8 to -6 °F: 1 day-6 to -4 °F: 2 days-4 to -2 °F: 14 days-2 to 0 °F: 7 days0 to 2 °F: 2 days2 to 4 °F: 0 days4 to 6 °F: 0 days6 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| 2.86 · P90 |e| 4.99 °F-200+20 °Fn = 27 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
-20.00-18.000
-18.00-16.000
-16.00-14.000
-14.00-12.000
-12.00-10.001
-10.00-8.000
-8.00-6.001
-6.00-4.002
-4.00-2.0014
-2.00+0.007
+0.00+2.002
+2.00+4.000
+4.00+6.000
+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
2026-08272.97 -2.91

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27
NCEP GFS2026-08-04 → 2026-08-30 27

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 27 -0.57 [-1.71, 0.62] no
GraphCast (IFS init) 25 -2.92 [-3.83, -2.13] yes
ECMWF IFS HRES 22 -2.49 [-3.87, -1.17] yes
Persistence (baseline) 27 +0.82 [-0.18, 1.78] no

Cite this page

ShortCastCheck, KSAN gfs lead 3, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAN/model/gfs/lead/3/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAN (San Diego Lindbergh), model gfs, lead day 3. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSAN/model/gfs/lead/3/

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