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CastCheck methodology v0.2 · data through 2026-08-30

San Francisco Intl · ECMWF AIFS Single · lead day 7

KSFO · aifs_single · lead 7

Target day = initialization date + 7 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, aifs-single-gpid5, 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
tmax00Zbilinear30d23 1 QC5.34 [4.44, 6.18]2.96-4.54 [-5.76, -3.26]6.02 [5.03, 6.84]0% [0%, 0%]9%26%-0.48+0.162026-08-08 → 2026-08-30
tmax00Zbilinear90d23 1 QC5.34 [4.33, 6.28]2.96-4.54 [-5.91, -3.01]6.02 [4.79, 6.85]0% [0%, 0%]9%26%-0.48+0.162026-08-08 → 2026-08-30
tmax00Zbilinear365d23 1 QC5.34 [4.21, 6.23]2.96-4.54 [-5.93, -2.92]6.02 [4.65, 6.86]0% [0%, 0%]9%26%-0.48+0.162026-08-08 → 2026-08-30
tmax00Zbilinearall23 1 QC5.34 [4.38, 6.25]2.96-4.54 [-6.01, -2.85]6.02 [4.92, 6.87]0% [0%, 0%]9%26%-0.48+0.162026-08-08 → 2026-08-30
tmax00Znearest30d23 1 QC3.24 [1.91, 4.85]3.17-1.10 [-2.25, 0.04]4.42 [2.66, 6.09]39% [13%, 63%]48%52%+0.10+0.092026-08-08 → 2026-08-30
tmax00Znearest90d23 1 QC3.24 [1.75, 5.08]3.17-1.10 [-2.25, 0.32]4.42 [2.39, 6.45]39% [9%, 64%]48%52%+0.10+0.092026-08-08 → 2026-08-30
tmax00Znearest365d23 1 QC3.24 [1.60, 5.31]3.17-1.10 [-2.35, 0.38]4.42 [2.32, 6.47]39% [8%, 67%]48%52%+0.10+0.092026-08-08 → 2026-08-30
tmax00Znearestall23 1 QC3.24 [1.77, 5.23]3.17-1.10 [-2.30, 0.45]4.42 [2.47, 6.61]39% [9%, 64%]48%52%+0.10+0.092026-08-08 → 2026-08-30
tmax12Zbilinear30d23 1 QC5.30 [4.27, 6.25]2.66-5.01 [-6.13, -3.90]5.98 [4.80, 6.97]0% [0%, 0%]13%26%-0.47+0.242026-08-08 → 2026-08-30
tmax12Zbilinear90d23 1 QC5.30 [4.06, 6.43]2.66-5.01 [-6.39, -3.63]5.98 [4.56, 7.08]0% [0%, 0%]13%26%-0.47+0.242026-08-08 → 2026-08-30
tmax12Zbilinear365d23 1 QC5.30 [4.03, 6.35]2.66-5.01 [-6.34, -3.55]5.98 [4.45, 6.96]0% [0%, 0%]13%26%-0.47+0.242026-08-08 → 2026-08-30
tmax12Zbilinearall23 1 QC5.30 [4.17, 6.47]2.66-5.01 [-6.46, -3.70]5.98 [4.68, 7.04]0% [0%, 0%]13%26%-0.47+0.242026-08-08 → 2026-08-30
tmax12Znearest30d23 1 QC3.01 [2.08, 3.94]2.76-1.41 [-2.40, -0.37]3.67 [2.62, 4.49]26% [15%, 38%]39%61%+0.17+0.212026-08-08 → 2026-08-30
tmax12Znearest90d23 1 QC3.01 [2.00, 4.01]2.76-1.41 [-2.48, -0.10]3.67 [2.45, 4.59]26% [16%, 38%]39%61%+0.17+0.212026-08-08 → 2026-08-30
tmax12Znearest365d23 1 QC3.01 [1.86, 4.01]2.76-1.41 [-2.54, -0.15]3.67 [2.16, 4.56]26% [14%, 39%]39%61%+0.17+0.212026-08-08 → 2026-08-30
tmax12Znearestall23 1 QC3.01 [1.99, 4.03]2.76-1.41 [-2.55, -0.25]3.67 [2.46, 4.55]26% [14%, 39%]39%61%+0.17+0.212026-08-08 → 2026-08-30
tmin00Zbilinear30d23 1 QC1.74 [0.98, 2.58]1.63-0.42 [-1.47, 1.00]2.22 [1.26, 3.11]30% [10%, 57%]61%91%-0.54-0.442026-08-08 → 2026-08-30
tmin00Zbilinear90d23 1 QC1.74 [0.82, 2.71]1.63-0.42 [-1.59, 1.26]2.22 [1.14, 3.29]30% [9%, 64%]61%91%-0.54-0.442026-08-08 → 2026-08-30
tmin00Zbilinear365d23 1 QC1.74 [0.81, 2.71]1.63-0.42 [-1.70, 1.33]2.22 [1.15, 3.30]30% [7%, 67%]61%91%-0.54-0.442026-08-08 → 2026-08-30
tmin00Zbilinearall23 1 QC1.74 [0.80, 2.66]1.63-0.42 [-1.58, 1.26]2.22 [1.11, 3.19]30% [10%, 65%]61%91%-0.54-0.442026-08-08 → 2026-08-30
tmin00Znearest30d23 1 QC2.02 [1.26, 3.07]2.02-0.00 [-1.29, 1.58]2.57 [1.34, 3.76]26% [8%, 47%]65%87%-0.79-0.792026-08-08 → 2026-08-30
tmin00Znearest90d23 1 QC2.02 [1.22, 3.23]2.02-0.00 [-1.51, 1.81]2.57 [1.29, 3.97]26% [6%, 50%]65%87%-0.79-0.792026-08-08 → 2026-08-30
tmin00Znearest365d23 1 QC2.02 [1.20, 3.30]2.02-0.00 [-1.64, 1.82]2.57 [1.28, 4.03]26% [0%, 50%]65%87%-0.79-0.792026-08-08 → 2026-08-30
tmin00Znearestall23 1 QC2.02 [1.21, 3.19]2.02-0.00 [-1.57, 1.78]2.57 [1.29, 3.92]26% [0%, 50%]65%87%-0.79-0.792026-08-08 → 2026-08-30
tmin12Zbilinear30d23 1 QC1.81 [1.43, 2.30]1.33-0.99 [-1.80, 0.22]2.02 [1.63, 2.50]26% [9%, 50%]61%96%-0.60-0.182026-08-08 → 2026-08-30
tmin12Zbilinear90d23 1 QC1.81 [1.33, 2.37]1.33-0.99 [-1.83, 0.54]2.02 [1.51, 2.59]26% [7%, 57%]61%96%-0.60-0.182026-08-08 → 2026-08-30
tmin12Zbilinear365d23 1 QC1.81 [1.35, 2.35]1.33-0.99 [-1.86, 0.59]2.02 [1.53, 2.54]26% [8%, 57%]61%96%-0.60-0.182026-08-08 → 2026-08-30
tmin12Zbilinearall23 1 QC1.81 [1.33, 2.41]1.33-0.99 [-1.89, 0.55]2.02 [1.52, 2.59]26% [5%, 56%]61%96%-0.60-0.182026-08-08 → 2026-08-30
tmin12Znearest30d23 1 QC1.80 [1.15, 2.63]1.62-0.60 [-1.57, 0.66]2.14 [1.39, 2.94]22% [0%, 48%]61%83%-0.59-0.432026-08-08 → 2026-08-30
tmin12Znearest90d23 1 QC1.80 [0.95, 2.85]1.62-0.60 [-1.64, 1.05]2.14 [1.15, 3.16]22% [0%, 57%]61%83%-0.59-0.432026-08-08 → 2026-08-30
tmin12Znearest365d23 1 QC1.80 [0.96, 2.78]1.62-0.60 [-1.66, 1.02]2.14 [1.18, 3.08]22% [0%, 57%]61%83%-0.59-0.432026-08-08 → 2026-08-30
tmin12Znearestall23 1 QC1.80 [0.94, 2.88]1.62-0.60 [-1.65, 0.99]2.14 [1.14, 3.13]22% [0%, 56%]61%83%-0.59-0.432026-08-08 → 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 ECMWF AIFS Single at KSFO, lead day 7, 00Z bilinear tmax+20+100-10-202026-08-08: -2.2 °F2026-08-09: -3.5 °F2026-08-10: -7.58 °F2026-08-11: -9.25 °F2026-08-12: -7.94 °F2026-08-13: -6.36 °F2026-08-14: -2.94 °F2026-08-15: -3.95 °F2026-08-16: -7.38 °F2026-08-17: -4.53 °F2026-08-18: -4.18 °F2026-08-19: -3.51 °F2026-08-20: -2.9 °F2026-08-21: -1.73 °F2026-08-22: -3.24 °F2026-08-23: -10.39 °F2026-08-24: -7.71 °F2026-08-25: +1.33 °F2026-08-26: -10.13 °F2026-08-27: -2.45 °F2026-08-28: +7.87 °F2026-08-29: -3.65 °F2026-08-30: -8.14 °F2026-08-082026-08-30°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 (23 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-8.14
2026-08-29-3.65
2026-08-28+7.87
2026-08-27-2.45
2026-08-26-10.13
2026-08-25+1.33
2026-08-24-7.71
2026-08-23-10.39
2026-08-22-3.24
2026-08-21-1.73
2026-08-20-2.90
2026-08-19-3.51
2026-08-18-4.18
2026-08-17-4.53
2026-08-16-7.38
2026-08-15-3.95
2026-08-14-2.94
2026-08-13-6.36
2026-08-12-7.94
2026-08-11-9.25
2026-08-10-7.58
2026-08-09-3.50
2026-08-08-2.20

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KSFO, lead day 7-20 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: 2 days-10 to -8 °F: 2 days-8 to -6 °F: 5 days-6 to -4 °F: 2 days-4 to -2 °F: 9 days-2 to 0 °F: 1 day0 to 2 °F: 1 day2 to 4 °F: 0 days4 to 6 °F: 0 days6 to 8 °F: 1 day8 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| 4.18 · P90 |e| 9.03 °F-200+20 °Fn = 23 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
-12.00-10.002
-10.00-8.002
-8.00-6.005
-6.00-4.002
-4.00-2.009
-2.00+0.001
+0.00+2.001
+2.00+4.000
+4.00+6.000
+6.00+8.001
+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
2026-08235.34 -4.54

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23
ECMWF AIFS Single2026-08-08 → 2026-08-30 23

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
NCEP GFS 23 +0.48 [-0.25, 1.39] no
GraphCast (IFS init) 23 -0.61 [-1.59, 1.14] no
ECMWF IFS HRES 18 -0.54 [-1.72, 1.53] no
Persistence (baseline) 23 +1.73 [-0.16, 3.08] no

Cite this page

ShortCastCheck, KSFO aifs_single lead 7, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSFO/model/aifs_single/lead/7/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSFO (San Francisco Intl), model aifs_single, lead day 7. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSFO/model/aifs_single/lead/7/

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