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 5

KSAN · gfs · lead 5

Target day = initialization date + 5 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
tmax00Zbilinear30d25 1 QC3.32 [2.39, 4.26]1.52-3.27 [-4.25, -2.26]3.88 [2.77, 4.89]12% [0%, 32%]24%48%-0.09+0.472026-08-06 → 2026-08-30
tmax00Zbilinear90d25 1 QC3.32 [2.29, 4.39]1.52-3.27 [-4.39, -2.16]3.88 [2.66, 4.94]12% [0%, 32%]24%48%-0.09+0.472026-08-06 → 2026-08-30
tmax00Zbilinear365d25 1 QC3.32 [2.20, 4.41]1.52-3.27 [-4.41, -2.08]3.88 [2.60, 5.02]12% [0%, 36%]24%48%-0.09+0.472026-08-06 → 2026-08-30
tmax00Zbilinearall25 1 QC3.32 [2.22, 4.42]1.52-3.27 [-4.42, -2.13]3.88 [2.62, 5.05]12% [0%, 32%]24%48%-0.09+0.472026-08-06 → 2026-08-30
tmax00Znearest30d25 1 QC5.68 [4.54, 6.91]1.59-5.68 [-6.91, -4.54]6.10 [4.70, 7.45]0% [0%, 0%]0%12%-0.87+0.442026-08-06 → 2026-08-30
tmax00Znearest90d25 1 QC5.68 [4.53, 7.00]1.59-5.68 [-7.00, -4.53]6.10 [4.71, 7.54]0% [0%, 0%]0%12%-0.87+0.442026-08-06 → 2026-08-30
tmax00Znearest365d25 1 QC5.68 [4.40, 7.15]1.59-5.68 [-7.15, -4.40]6.10 [4.60, 7.70]0% [0%, 0%]0%12%-0.87+0.442026-08-06 → 2026-08-30
tmax00Znearestall25 1 QC5.68 [4.48, 7.14]1.59-5.68 [-7.14, -4.48]6.10 [4.63, 7.70]0% [0%, 0%]0%12%-0.87+0.442026-08-06 → 2026-08-30
tmax12Zbilinear30d25 1 QC3.35 [2.34, 4.31]1.53-3.35 [-4.31, -2.34]3.92 [2.80, 4.88]8% [0%, 20%]32%40%-0.10+0.462026-08-06 → 2026-08-30
tmax12Zbilinear90d25 1 QC3.35 [2.30, 4.44]1.53-3.35 [-4.44, -2.30]3.92 [2.78, 5.02]8% [0%, 21%]32%40%-0.10+0.462026-08-06 → 2026-08-30
tmax12Zbilinear365d25 1 QC3.35 [2.22, 4.48]1.53-3.35 [-4.48, -2.22]3.92 [2.67, 5.16]8% [0%, 21%]32%40%-0.10+0.462026-08-06 → 2026-08-30
tmax12Zbilinearall25 1 QC3.35 [2.26, 4.45]1.53-3.35 [-4.45, -2.26]3.92 [2.76, 5.05]8% [0%, 20%]32%40%-0.10+0.462026-08-06 → 2026-08-30
tmax12Znearest30d25 1 QC5.79 [4.66, 7.00]1.69-5.79 [-7.00, -4.66]6.20 [4.85, 7.53]0% [0%, 0%]0%4%-0.90+0.412026-08-06 → 2026-08-30
tmax12Znearest90d25 1 QC5.79 [4.65, 7.16]1.69-5.79 [-7.16, -4.65]6.20 [4.84, 7.64]0% [0%, 0%]0%4%-0.90+0.412026-08-06 → 2026-08-30
tmax12Znearest365d25 1 QC5.79 [4.51, 7.32]1.69-5.79 [-7.32, -4.51]6.20 [4.67, 7.81]0% [0%, 0%]0%4%-0.90+0.412026-08-06 → 2026-08-30
tmax12Znearestall25 1 QC5.79 [4.55, 7.27]1.69-5.79 [-7.27, -4.55]6.20 [4.69, 7.72]0% [0%, 0%]0%4%-0.90+0.412026-08-06 → 2026-08-30
tmin00Zbilinear30d25 1 QC2.46 [1.46, 3.32]1.32+2.35 [1.32, 3.28]2.89 [1.82, 3.69]16% [3%, 40%]40%68%-0.62+0.042026-08-06 → 2026-08-30
tmin00Zbilinear90d25 1 QC2.46 [1.35, 3.46]1.32+2.35 [1.23, 3.39]2.89 [1.73, 3.78]16% [0%, 46%]40%68%-0.62+0.042026-08-06 → 2026-08-30
tmin00Zbilinear365d25 1 QC2.46 [1.36, 3.57]1.32+2.35 [1.31, 3.54]2.89 [1.75, 3.87]16% [0%, 45%]40%68%-0.62+0.042026-08-06 → 2026-08-30
tmin00Zbilinearall25 1 QC2.46 [1.31, 3.53]1.32+2.35 [1.18, 3.49]2.89 [1.73, 3.84]16% [0%, 56%]40%68%-0.62+0.042026-08-06 → 2026-08-30
tmin00Znearest30d25 1 QC1.87 [1.19, 2.54]1.12+1.59 [0.73, 2.41]2.19 [1.39, 2.83]16% [0%, 38%]64%84%-0.23+0.192026-08-06 → 2026-08-30
tmin00Znearest90d25 1 QC1.87 [1.10, 2.63]1.12+1.59 [0.59, 2.53]2.19 [1.32, 2.91]16% [0%, 42%]64%84%-0.23+0.192026-08-06 → 2026-08-30
tmin00Znearest365d25 1 QC1.87 [1.14, 2.72]1.12+1.59 [0.57, 2.57]2.19 [1.34, 2.95]16% [0%, 40%]64%84%-0.23+0.192026-08-06 → 2026-08-30
tmin00Znearestall25 1 QC1.87 [1.09, 2.65]1.12+1.59 [0.43, 2.53]2.19 [1.29, 2.92]16% [0%, 43%]64%84%-0.23+0.192026-08-06 → 2026-08-30
tmin12Zbilinear30d25 1 QC2.43 [1.49, 3.27]1.31+2.21 [1.15, 3.25]2.80 [1.85, 3.54]16% [4%, 40%]36%64%-0.60+0.052026-08-06 → 2026-08-30
tmin12Zbilinear90d25 1 QC2.43 [1.42, 3.34]1.31+2.21 [0.98, 3.28]2.80 [1.74, 3.58]16% [4%, 44%]36%64%-0.60+0.052026-08-06 → 2026-08-30
tmin12Zbilinear365d25 1 QC2.43 [1.41, 3.42]1.31+2.21 [1.04, 3.42]2.80 [1.74, 3.67]16% [0%, 44%]36%64%-0.60+0.052026-08-06 → 2026-08-30
tmin12Zbilinearall25 1 QC2.43 [1.33, 3.53]1.31+2.21 [0.99, 3.53]2.80 [1.68, 3.69]16% [0%, 50%]36%64%-0.60+0.052026-08-06 → 2026-08-30
tmin12Znearest30d25 1 QC1.73 [1.12, 2.32]1.20+1.42 [0.59, 2.23]2.06 [1.40, 2.57]36% [16%, 62%]56%88%-0.14+0.132026-08-06 → 2026-08-30
tmin12Znearest90d25 1 QC1.73 [1.00, 2.40]1.20+1.42 [0.51, 2.31]2.06 [1.28, 2.65]36% [12%, 67%]56%88%-0.14+0.132026-08-06 → 2026-08-30
tmin12Znearest365d25 1 QC1.73 [1.00, 2.43]1.20+1.42 [0.53, 2.35]2.06 [1.28, 2.65]36% [12%, 70%]56%88%-0.14+0.132026-08-06 → 2026-08-30
tmin12Znearestall25 1 QC1.73 [0.94, 2.43]1.20+1.42 [0.41, 2.39]2.06 [1.22, 2.66]36% [14%, 75%]56%88%-0.14+0.132026-08-06 → 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 5, 00Z bilinear tmax+20+100-10-202026-08-06: -4.73 °F2026-08-07: -4.42 °F2026-08-08: -4.39 °F2026-08-09: -4.76 °F2026-08-10: -3.97 °F2026-08-11: -2.93 °F2026-08-12: -2.96 °F2026-08-13: -1.26 °F2026-08-14: -4.06 °F2026-08-15: -4.49 °F2026-08-16: -2.38 °F2026-08-17: -2.12 °F2026-08-18: -0.69 °F2026-08-19: -0.35 °F2026-08-20: +0.67 °F2026-08-21: -3.11 °F2026-08-22: -2.41 °F2026-08-23: -5.02 °F2026-08-24: -1.97 °F2026-08-25: -4.99 °F2026-08-26: -10.42 °F2026-08-27: -3.52 °F2026-08-28: -1.62 °F2026-08-29: -3.43 °F2026-08-30: -2.38 °F2026-08-062026-08-30°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 (25 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.38
2026-08-29-3.43
2026-08-28-1.62
2026-08-27-3.52
2026-08-26-10.42
2026-08-25-4.99
2026-08-24-1.97
2026-08-23-5.02
2026-08-22-2.41
2026-08-21-3.11
2026-08-20+0.67
2026-08-19-0.35
2026-08-18-0.69
2026-08-17-2.12
2026-08-16-2.38
2026-08-15-4.49
2026-08-14-4.06
2026-08-13-1.26
2026-08-12-2.96
2026-08-11-2.93
2026-08-10-3.97
2026-08-09-4.76
2026-08-08-4.39
2026-08-07-4.42
2026-08-06-4.73

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAN, lead day 5-20 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: 0 days-6 to -4 °F: 8 days-4 to -2 °F: 10 days-2 to 0 °F: 5 days0 to 2 °F: 1 day2 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| 3.11 · P90 |e| 4.9 °F-200+20 °Fn = 25 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
-8.00-6.000
-6.00-4.008
-4.00-2.0010
-2.00+0.005
+0.00+2.001
+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
2026-08253.32 -3.27

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25
NCEP GFS2026-08-06 → 2026-08-30 25

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 25 -0.16 [-1.13, 0.73] no
GraphCast (IFS init) 25 -2.28 [-3.48, -1.13] yes
ECMWF IFS HRES 18 -2.67 [-4.20, -0.95] yes
Persistence (baseline) 25 +0.28 [-0.73, 1.80] no

Cite this page

ShortCastCheck, KSAN gfs lead 5, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAN/model/gfs/lead/5/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAN (San Diego Lindbergh), model gfs, lead day 5. 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/5/

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