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

San Francisco Intl · ECMWF IFS HRES · lead day 6

KSFO · ifs_hres · lead 6

Target day = initialization date + 6 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, ifs-gpid161, 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
tmax00Zbilinear30d19 1 QC5.98 [3.89, 7.33]2.69-5.91 [-7.25, -3.80]6.72 [4.50, 7.94]5% [0%, 17%]16%16%-0.78+0.172026-08-07 → 2026-08-30
tmax00Zbilinear90d19 1 QC5.98 [3.63, 7.31]2.69-5.91 [-7.25, -3.63]6.72 [3.63, 7.94]5% [0%, 18%]16%16%-0.78+0.172026-08-07 → 2026-08-30
tmax00Zbilinear365d19 1 QC5.98 [3.63, 7.43]2.69-5.91 [-7.33, -3.63]6.72 [3.63, 8.07]5% [0%, 17%]16%16%-0.78+0.172026-08-07 → 2026-08-30
tmax00Zbilinearall19 1 QC5.98 [3.63, 7.54]2.69-5.91 [-7.47, -3.63]6.72 [3.63, 8.04]5% [0%, 17%]16%16%-0.78+0.172026-08-07 → 2026-08-30
tmax00Znearest30d19 1 QC3.44 [2.84, 4.50]3.28-1.07 [-2.40, 1.49]4.02 [3.30, 4.94]11% [0%, 19%]32%42%-0.02-0.022026-08-07 → 2026-08-30
tmax00Znearest90d19 1 QC3.44 [2.82, 4.68]3.28-1.07 [-2.35, 3.21]4.02 [3.28, 5.01]11% [0%, 19%]32%42%-0.02-0.022026-08-07 → 2026-08-30
tmax00Znearest365d19 1 QC3.44 [2.77, 4.68]3.28-1.07 [-2.60, 3.40]4.02 [3.23, 5.00]11% [0%, 20%]32%42%-0.02-0.022026-08-07 → 2026-08-30
tmax00Znearestall19 1 QC3.44 [2.82, 4.68]3.28-1.07 [-2.62, 3.11]4.02 [3.25, 4.99]11% [0%, 20%]32%42%-0.02-0.022026-08-07 → 2026-08-30
tmax12Zbilinear30d19 1 QC5.85 [4.21, 6.91]2.55-5.85 [-6.91, -4.21]6.66 [4.81, 7.64]5% [0%, 17%]5%21%-0.74+0.212026-08-07 → 2026-08-30
tmax12Zbilinear90d19 1 QC5.85 [4.00, 6.86]2.55-5.85 [-6.86, -4.00]6.66 [4.10, 7.59]5% [0%, 18%]5%21%-0.74+0.212026-08-07 → 2026-08-30
tmax12Zbilinear365d19 1 QC5.85 [4.10, 7.10]2.55-5.85 [-7.10, -4.10]6.66 [4.10, 7.74]5% [0%, 17%]5%21%-0.74+0.212026-08-07 → 2026-08-30
tmax12Zbilinearall19 1 QC5.85 [4.08, 7.02]2.55-5.85 [-7.02, -4.08]6.66 [4.10, 7.75]5% [0%, 17%]5%21%-0.74+0.212026-08-07 → 2026-08-30
tmax12Znearest30d19 1 QC2.87 [2.30, 3.65]2.95-0.79 [-1.86, 1.25]3.86 [3.14, 4.46]32% [12%, 50%]47%63%+0.15+0.092026-08-07 → 2026-08-30
tmax12Znearest90d19 1 QC2.87 [2.26, 3.88]2.95-0.79 [-1.76, 3.13]3.86 [3.07, 4.55]32% [0%, 50%]47%63%+0.15+0.092026-08-07 → 2026-08-30
tmax12Znearest365d19 1 QC2.87 [2.16, 3.82]2.95-0.79 [-2.06, 2.88]3.86 [2.94, 4.65]32% [0%, 50%]47%63%+0.15+0.092026-08-07 → 2026-08-30
tmax12Znearestall19 1 QC2.87 [2.17, 3.94]2.95-0.79 [-2.00, 2.75]3.86 [2.98, 4.65]32% [0%, 51%]47%63%+0.15+0.092026-08-07 → 2026-08-30
tmin00Zbilinear30d19 1 QC0.89 [0.62, 1.15]0.87-0.38 [-0.91, 0.10]1.07 [0.72, 1.29]68% [42%, 89%]95%100%+0.15+0.202026-08-07 → 2026-08-30
tmin00Zbilinear90d19 1 QC0.89 [0.64, 1.19]0.87-0.38 [-1.06, 0.09]1.07 [0.72, 1.29]68% [33%, 89%]95%100%+0.15+0.202026-08-07 → 2026-08-30
tmin00Zbilinear365d19 1 QC0.89 [0.59, 1.19]0.87-0.38 [-1.17, 0.14]1.07 [0.67, 1.29]68% [24%, 92%]95%100%+0.15+0.202026-08-07 → 2026-08-30
tmin00Zbilinearall19 1 QC0.89 [0.60, 1.19]0.87-0.38 [-1.19, 0.07]1.07 [0.67, 1.30]68% [24%, 92%]95%100%+0.15+0.202026-08-07 → 2026-08-30
tmin00Znearest30d19 1 QC0.99 [0.67, 1.25]0.88-0.68 [-1.14, -0.22]1.27 [0.93, 1.54]47% [33%, 64%]84%100%+0.06+0.192026-08-07 → 2026-08-30
tmin00Znearest90d19 1 QC0.99 [0.62, 1.29]0.88-0.68 [-1.20, -0.09]1.27 [0.90, 1.58]47% [33%, 71%]84%100%+0.06+0.192026-08-07 → 2026-08-30
tmin00Znearest365d19 1 QC0.99 [0.59, 1.27]0.88-0.68 [-1.21, -0.08]1.27 [0.82, 1.59]47% [33%, 75%]84%100%+0.06+0.192026-08-07 → 2026-08-30
tmin00Znearestall19 1 QC0.99 [0.63, 1.29]0.88-0.68 [-1.22, -0.13]1.27 [0.86, 1.59]47% [31%, 70%]84%100%+0.06+0.192026-08-07 → 2026-08-30
tmin12Zbilinear30d19 1 QC0.84 [0.60, 1.23]0.82-0.32 [-0.95, 0.08]1.05 [0.78, 1.33]63% [33%, 77%]95%100%+0.20+0.242026-08-07 → 2026-08-30
tmin12Zbilinear90d19 1 QC0.84 [0.61, 1.37]0.82-0.32 [-1.30, 0.10]1.05 [0.78, 1.42]63% [20%, 78%]95%100%+0.20+0.242026-08-07 → 2026-08-30
tmin12Zbilinear365d19 1 QC0.84 [0.58, 1.40]0.82-0.32 [-1.40, 0.12]1.05 [0.75, 1.42]63% [0%, 79%]95%100%+0.20+0.242026-08-07 → 2026-08-30
tmin12Zbilinearall19 1 QC0.84 [0.58, 1.37]0.82-0.32 [-1.34, 0.08]1.05 [0.75, 1.42]63% [0%, 79%]95%100%+0.20+0.242026-08-07 → 2026-08-30
tmin12Znearest30d19 1 QC1.02 [0.78, 1.31]0.98-0.50 [-1.15, -0.02]1.27 [1.01, 1.51]53% [31%, 71%]89%100%+0.04+0.102026-08-07 → 2026-08-30
tmin12Znearest90d19 1 QC1.02 [0.73, 1.40]0.98-0.50 [-1.31, -0.00]1.27 [0.97, 1.55]53% [22%, 75%]89%100%+0.04+0.102026-08-07 → 2026-08-30
tmin12Znearest365d19 1 QC1.02 [0.70, 1.39]0.98-0.50 [-1.30, 0.03]1.27 [0.92, 1.56]53% [25%, 75%]89%100%+0.04+0.102026-08-07 → 2026-08-30
tmin12Znearestall19 1 QC1.02 [0.70, 1.36]0.98-0.50 [-1.29, -0.04]1.27 [0.91, 1.53]53% [25%, 76%]89%100%+0.04+0.102026-08-07 → 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 IFS HRES at KSFO, lead day 6, 00Z bilinear tmax+20+100-10-202026-08-07: -3.63 °F2026-08-13: -3.16 °F2026-08-14: -1.79 °F2026-08-15: -1.74 °F2026-08-16: -5.69 °F2026-08-17: -8.76 °F2026-08-18: -5.11 °F2026-08-19: -3.5 °F2026-08-20: -7.69 °F2026-08-21: -5.45 °F2026-08-22: -6.02 °F2026-08-23: -10.91 °F2026-08-24: -9.84 °F2026-08-25: -4.22 °F2026-08-26: -10.92 °F2026-08-27: -7.53 °F2026-08-28: +0.68 °F2026-08-29: -8.01 °F2026-08-30: -9.06 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-9.06
2026-08-29-8.01
2026-08-28+0.68
2026-08-27-7.53
2026-08-26-10.92
2026-08-25-4.22
2026-08-24-9.84
2026-08-23-10.91
2026-08-22-6.02
2026-08-21-5.45
2026-08-20-7.69
2026-08-19-3.50
2026-08-18-5.11
2026-08-17-8.76
2026-08-16-5.69
2026-08-15-1.74
2026-08-14-1.79
2026-08-13-3.16
2026-08-12—
2026-08-11—
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07-3.63

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KSFO, lead day 6-20 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: 4 days-8 to -6 °F: 3 days-6 to -4 °F: 4 days-4 to -2 °F: 3 days-2 to 0 °F: 2 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| 5.69 · P90 |e| 10.06 °F-200+20 °Fn = 19 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
-10.00-8.004
-8.00-6.003
-6.00-4.004
-4.00-2.003
-2.00+0.002
+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
2026-08195.98 -5.91

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-07 → 2026-08-30 19
ECMWF IFS HRES2026-08-07 → 2026-08-30 19
ECMWF IFS HRES2026-08-07 → 2026-08-30 19
ECMWF IFS HRES2026-08-07 → 2026-08-30 19

Compared with other models

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

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 19 +1.50 [-0.53, 2.68] no
NCEP GFS 19 +1.65 [0.77, 2.57] yes
GraphCast (IFS init) 19 +0.82 [-1.39, 2.31] no
Persistence (baseline) 19 +2.62 [-0.95, 4.12] no

Cite this page

ShortCastCheck, KSFO ifs_hres lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSFO/model/ifs_hres/lead/6/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSFO (San Francisco Intl), model ifs_hres, lead day 6. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSFO/model/ifs_hres/lead/6/

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