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 · GraphCast (IFS init) · lead day 1

KSAN · graphcast_ifs · 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, 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, 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 QC5.88 [5.23, 6.70]1.27-5.88 [-6.70, -5.23]6.11 [5.35, 7.06]0% [0%, 0%]0%4%-2.45+0.272026-08-02 → 2026-08-30
tmax00Zbilinear90d27 1 QC5.88 [5.20, 6.73]1.27-5.88 [-6.73, -5.20]6.11 [5.31, 7.07]0% [0%, 0%]0%4%-2.45+0.272026-08-02 → 2026-08-30
tmax00Zbilinear365d33 1 QC5.53 [4.64, 6.43]1.32-5.53 [-6.43, -4.64]5.79 [4.80, 6.77]0% [0%, 0%]0%3%-2.44+0.192026-01-02 → 2026-08-30
tmax00Zbilinearall33 1 QC5.53 [4.69, 6.41]1.32-5.53 [-6.41, -4.69]5.79 [4.87, 6.77]0% [0%, 0%]0%3%-2.44+0.192026-01-02 → 2026-08-30
tmax00Znearest30d27 1 QC7.90 [6.89, 9.18]1.51-7.90 [-9.18, -6.89]8.16 [7.03, 9.53]0% [0%, 0%]0%0%-3.64+0.132026-08-02 → 2026-08-30
tmax00Znearest90d27 1 QC7.90 [6.90, 9.18]1.51-7.90 [-9.18, -6.90]8.16 [7.03, 9.58]0% [0%, 0%]0%0%-3.64+0.132026-08-02 → 2026-08-30
tmax00Znearest365d33 1 QC7.16 [5.54, 8.74]1.86-7.16 [-8.74, -5.54]7.56 [5.88, 9.13]0% [0%, 0%]0%3%-3.46-0.142026-01-02 → 2026-08-30
tmax00Znearestall33 1 QC7.16 [5.52, 8.68]1.86-7.16 [-8.68, -5.52]7.56 [5.90, 9.04]0% [0%, 0%]0%3%-3.46-0.142026-01-02 → 2026-08-30
tmax12Zbilinear30d27 1 QC5.77 [5.14, 6.56]1.18-5.77 [-6.56, -5.14]5.99 [5.24, 6.90]0% [0%, 0%]0%0%-2.39+0.322026-08-02 → 2026-08-30
tmax12Zbilinear90d27 1 QC5.77 [5.08, 6.55]1.18-5.77 [-6.55, -5.08]5.99 [5.22, 6.90]0% [0%, 0%]0%0%-2.39+0.322026-08-02 → 2026-08-30
tmax12Zbilinear365d32 1 QC5.49 [4.63, 6.31]1.23-5.49 [-6.31, -4.63]5.73 [4.77, 6.64]0% [0%, 0%]0%0%-2.31+0.272026-01-02 → 2026-08-30
tmax12Zbilinearall32 1 QC5.49 [4.71, 6.28]1.23-5.49 [-6.28, -4.71]5.73 [4.85, 6.61]0% [0%, 0%]0%0%-2.31+0.272026-01-02 → 2026-08-30
tmax12Znearest30d27 1 QC7.79 [6.83, 9.06]1.47-7.79 [-9.06, -6.83]8.03 [6.92, 9.43]0% [0%, 0%]0%0%-3.57+0.152026-08-02 → 2026-08-30
tmax12Znearest90d27 1 QC7.79 [6.84, 9.07]1.47-7.79 [-9.07, -6.84]8.03 [6.92, 9.41]0% [0%, 0%]0%0%-3.57+0.152026-08-02 → 2026-08-30
tmax12Znearest365d32 1 QC7.19 [5.61, 8.66]1.71-7.19 [-8.66, -5.61]7.55 [5.96, 9.01]0% [0%, 0%]0%0%-3.34-0.022026-01-02 → 2026-08-30
tmax12Znearestall32 1 QC7.19 [5.67, 8.62]1.71-7.19 [-8.62, -5.67]7.55 [6.03, 8.98]0% [0%, 0%]0%0%-3.34-0.022026-01-02 → 2026-08-30
tmin00Zbilinear30d27 1 QC1.08 [0.84, 1.38]0.75-0.77 [-1.25, -0.28]1.26 [0.98, 1.57]44% [17%, 70%]96%96%-0.46+0.072026-08-02 → 2026-08-30
tmin00Zbilinear90d27 1 QC1.08 [0.79, 1.44]0.75-0.77 [-1.29, -0.22]1.26 [0.93, 1.63]44% [14%, 71%]96%96%-0.46+0.072026-08-02 → 2026-08-30
tmin00Zbilinear365d33 1 QC1.25 [0.85, 1.76]1.18-0.27 [-1.07, 0.86]1.54 [1.02, 2.07]42% [18%, 68%]85%91%-0.38-0.262026-01-02 → 2026-08-30
tmin00Zbilinearall33 1 QC1.25 [0.84, 1.80]1.18-0.27 [-1.12, 0.84]1.54 [1.01, 2.10]42% [18%, 67%]85%91%-0.38-0.262026-01-02 → 2026-08-30
tmin00Znearest30d27 1 QC0.76 [0.50, 1.00]0.76-0.04 [-0.52, 0.42]1.02 [0.64, 1.26]74% [61%, 88%]89%100%-0.03+0.072026-08-02 → 2026-08-30
tmin00Znearest90d27 1 QC0.76 [0.49, 1.01]0.76-0.04 [-0.57, 0.46]1.02 [0.61, 1.27]74% [60%, 89%]89%100%-0.03+0.072026-08-02 → 2026-08-30
tmin00Znearest365d33 1 QC1.19 [0.61, 2.12]1.26+0.54 [-0.34, 1.76]1.74 [0.80, 2.74]64% [40%, 83%]79%88%-0.31-0.352026-01-02 → 2026-08-30
tmin00Znearestall33 1 QC1.19 [0.60, 2.19]1.26+0.54 [-0.36, 1.74]1.74 [0.79, 2.77]64% [40%, 84%]79%88%-0.31-0.352026-01-02 → 2026-08-30
tmin12Zbilinear30d27 1 QC1.08 [0.79, 1.38]0.86-0.61 [-1.20, 0.01]1.27 [1.00, 1.54]48% [28%, 72%]85%100%-0.46-0.062026-08-02 → 2026-08-30
tmin12Zbilinear90d27 1 QC1.08 [0.78, 1.43]0.86-0.61 [-1.25, 0.08]1.27 [0.97, 1.58]48% [25%, 72%]85%100%-0.46-0.062026-08-02 → 2026-08-30
tmin12Zbilinear365d32 1 QC1.22 [0.84, 1.67]1.14-0.23 [-1.05, 0.83]1.51 [1.05, 2.05]47% [27%, 69%]78%94%-0.30-0.192026-01-02 → 2026-08-30
tmin12Zbilinearall32 1 QC1.22 [0.83, 1.73]1.14-0.23 [-1.11, 0.77]1.51 [1.05, 2.06]47% [26%, 68%]78%94%-0.30-0.192026-01-02 → 2026-08-30
tmin12Znearest30d27 1 QC0.87 [0.65, 1.12]0.88+0.17 [-0.38, 0.73]1.14 [0.82, 1.41]63% [45%, 77%]89%100%-0.17-0.092026-08-02 → 2026-08-30
tmin12Znearest90d27 1 QC0.87 [0.63, 1.15]0.88+0.17 [-0.44, 0.77]1.14 [0.81, 1.42]63% [44%, 79%]89%100%-0.17-0.092026-08-02 → 2026-08-30
tmin12Znearest365d32 1 QC1.18 [0.70, 1.96]1.19+0.59 [-0.23, 1.69]1.70 [0.91, 2.63]59% [40%, 76%]81%91%-0.26-0.232026-01-02 → 2026-08-30
tmin12Znearestall32 1 QC1.18 [0.69, 1.98]1.19+0.59 [-0.28, 1.66]1.70 [0.88, 2.65]59% [40%, 76%]81%91%-0.26-0.232026-01-02 → 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 GraphCast (IFS init) at KSAN, lead day 1, 00Z bilinear tmax+20+100-10-202026-08-02: -6.57 °F2026-08-03: -5.15 °F2026-08-04: -5.09 °F2026-08-05: -7.17 °F2026-08-06: -6.76 °F2026-08-07: -4.73 °F2026-08-08: -4.2 °F2026-08-09: -6.45 °F2026-08-10: -7.33 °F2026-08-11: -5.86 °F2026-08-12: -5.35 °F2026-08-13: -3.25 °F2026-08-14: -5.05 °F2026-08-15: -5.38 °F2026-08-16: -4.24 °F2026-08-17: -5.72 °F2026-08-18: -4.54 °F2026-08-19: -5 °F2026-08-20: -6.24 °F2026-08-21: -6.5 °F2026-08-22: -4.74 °F2026-08-23: -9.21 °F2026-08-24: -6.05 °F2026-08-25: -6.56 °F2026-08-26: -10.88 °F2026-08-29: -7.92 °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
2026-08-29-7.92
2026-08-28—
2026-08-27—
2026-08-26-10.88
2026-08-25-6.56
2026-08-24-6.05
2026-08-23-9.21
2026-08-22-4.74
2026-08-21-6.50
2026-08-20-6.24
2026-08-19-5.00
2026-08-18-4.54
2026-08-17-5.72
2026-08-16-4.24
2026-08-15-5.38
2026-08-14-5.05
2026-08-13-3.25
2026-08-12-5.35
2026-08-11-5.86
2026-08-10-7.33
2026-08-09-6.45
2026-08-08-4.20
2026-08-07-4.73
2026-08-06-6.76
2026-08-05-7.17
2026-08-04-5.09
2026-08-03-5.15
2026-08-02-6.57

Error distribution

Distribution of the signed daily error in °F for GraphCast (IFS init) at KSAN, lead day 1-20 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: 1 day-8 to -6 °F: 10 days-6 to -4 °F: 16 days-4 to -2 °F: 5 days-2 to 0 °F: 0 days0 to 2 °F: 0 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| 5.15 · P90 |e| 7.3 °F-200+20 °Fn = 33 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
-10.00-8.001
-8.00-6.0010
-6.00-4.0016
-4.00-2.005
-2.00+0.000
+0.00+2.000
+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
2026-08275.88 -5.88
2026-0163.97 -3.97

Availability

ModelScored period DaysCoverage
GraphCast (IFS init)2026-01-02 → 2026-08-30 33
GraphCast (IFS init)2026-01-02 → 2026-08-30 33
GraphCast (IFS init)2026-01-02 → 2026-08-30 32
GraphCast (IFS init)2026-01-02 → 2026-08-30 32

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 27 +1.84 [1.29, 2.56] yes
Aurora (GFS init) 1 -1.35 [-1.35, -1.35] yes
Aurora (IFS init) 2 +0.14 [-0.50, 0.77] no
FourCastNet v2 (GFS init) 1 +2.17 [2.17, 2.17] yes
FourCastNet v2 (IFS init) 2 +2.76 [2.56, 2.96] yes
NCEP GFS 27 +3.10 [2.17, 3.98] yes
GraphCast (GFS init) 1 -0.79 [-0.79, -0.79] yes
ECMWF IFS HRES 20 +0.09 [-0.27, 0.75] no
Pangu-Weather (GFS init) 1 -2.26 [-2.26, -2.26] yes
Pangu-Weather (IFS init) 2 -1.09 [-1.78, -0.40] yes
Persistence (baseline) 27 +4.17 [3.15, 4.75] yes

Cite this page

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

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