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

San Francisco Intl · ECMWF IFS HRES · lead day 8

KSFO · ifs_hres · lead 8

Target day = initialization date + 8 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
tmax00Zbilinear30d17 1 QC5.37 [4.16, 6.35]2.10-5.14 [-6.06, -3.94]5.80 [4.44, 6.82]0% [0%, 0%]6%18%-0.43+0.442026-08-09 → 2026-08-30
tmax00Zbilinear90d17 1 QC5.37 [4.11, 6.36]2.10-5.14 [-6.06, -3.66]5.80 [4.42, 6.86]0% [0%, 0%]6%18%-0.43+0.442026-08-09 → 2026-08-30
tmax00Zbilinear365d17 1 QC5.37 [4.11, 6.49]2.10-5.14 [-6.17, -3.65]5.80 [4.41, 6.89]0% [0%, 0%]6%18%-0.43+0.442026-08-09 → 2026-08-30
tmax00Zbilinearall17 1 QC5.37 [4.02, 6.48]2.10-5.14 [-6.17, -3.73]5.80 [4.22, 6.88]0% [0%, 0%]6%18%-0.43+0.442026-08-09 → 2026-08-30
tmax00Znearest30d17 1 QC2.20 [1.36, 3.59]2.27+0.28 [-0.61, 2.29]3.01 [1.89, 4.25]35% [0%, 57%]53%76%+0.42+0.402026-08-09 → 2026-08-30
tmax00Znearest90d17 1 QC2.20 [1.33, 3.81]2.27+0.28 [-0.64, 3.22]3.01 [1.82, 4.44]35% [0%, 57%]53%76%+0.42+0.402026-08-09 → 2026-08-30
tmax00Znearest365d17 1 QC2.20 [1.32, 3.77]2.27+0.28 [-0.73, 3.22]3.01 [1.78, 4.38]35% [0%, 57%]53%76%+0.42+0.402026-08-09 → 2026-08-30
tmax00Znearestall17 1 QC2.20 [1.22, 3.74]2.27+0.28 [-0.75, 3.22]3.01 [1.61, 4.36]35% [0%, 57%]53%76%+0.42+0.402026-08-09 → 2026-08-30
tmax12Zbilinear30d17 1 QC6.40 [4.59, 7.83]2.43-6.40 [-7.83, -4.59]7.30 [5.14, 8.79]6% [0%, 18%]6%18%-0.70+0.352026-08-09 → 2026-08-30
tmax12Zbilinear90d17 1 QC6.40 [4.30, 7.86]2.43-6.40 [-7.86, -4.30]7.30 [4.80, 8.84]6% [0%, 20%]6%18%-0.70+0.352026-08-09 → 2026-08-30
tmax12Zbilinear365d17 1 QC6.40 [4.30, 8.01]2.43-6.40 [-8.01, -4.30]7.30 [4.76, 8.99]6% [0%, 18%]6%18%-0.70+0.352026-08-09 → 2026-08-30
tmax12Zbilinearall17 1 QC6.40 [4.41, 8.12]2.43-6.40 [-8.12, -4.41]7.30 [4.97, 9.00]6% [0%, 17%]6%18%-0.70+0.352026-08-09 → 2026-08-30
tmax12Znearest30d17 1 QC3.39 [1.99, 4.42]3.12-1.45 [-3.15, 1.54]4.36 [2.21, 5.46]18% [6%, 31%]29%59%+0.10+0.172026-08-09 → 2026-08-30
tmax12Znearest90d17 1 QC3.39 [1.86, 4.51]3.12-1.45 [-3.22, 2.16]4.36 [1.86, 5.51]18% [0%, 33%]29%59%+0.10+0.172026-08-09 → 2026-08-30
tmax12Znearest365d17 1 QC3.39 [1.86, 4.48]3.12-1.45 [-3.56, 2.16]4.36 [1.86, 5.52]18% [0%, 33%]29%59%+0.10+0.172026-08-09 → 2026-08-30
tmax12Znearestall17 1 QC3.39 [1.86, 4.50]3.12-1.45 [-3.53, 2.09]4.36 [1.86, 5.54]18% [0%, 33%]29%59%+0.10+0.172026-08-09 → 2026-08-30
tmin00Zbilinear30d17 1 QC1.38 [0.86, 1.76]1.39+0.19 [-0.71, 1.29]1.67 [1.03, 2.08]29% [18%, 56%]76%94%-0.68-0.502026-08-09 → 2026-08-30
tmin00Zbilinear90d17 1 QC1.38 [0.60, 1.78]1.39+0.19 [-0.71, 1.39]1.67 [0.77, 2.10]29% [17%, 67%]76%94%-0.68-0.502026-08-09 → 2026-08-30
tmin00Zbilinear365d17 1 QC1.38 [0.57, 1.81]1.39+0.19 [-0.74, 1.50]1.67 [0.78, 2.12]29% [14%, 75%]76%94%-0.68-0.502026-08-09 → 2026-08-30
tmin00Zbilinearall17 1 QC1.38 [0.63, 1.77]1.39+0.19 [-0.71, 1.50]1.67 [0.87, 2.08]29% [16%, 67%]76%94%-0.68-0.502026-08-09 → 2026-08-30
tmin00Znearest30d17 1 QC1.74 [1.22, 2.04]1.71-0.23 [-1.26, 1.08]2.12 [1.53, 2.44]35% [19%, 56%]59%82%-1.11-0.842026-08-09 → 2026-08-30
tmin00Znearest90d17 1 QC1.74 [0.95, 2.09]1.71-0.23 [-1.28, 1.25]2.12 [1.26, 2.46]35% [15%, 65%]59%82%-1.11-0.842026-08-09 → 2026-08-30
tmin00Znearest365d17 1 QC1.74 [0.93, 2.09]1.71-0.23 [-1.30, 1.30]2.12 [1.23, 2.47]35% [17%, 67%]59%82%-1.11-0.842026-08-09 → 2026-08-30
tmin00Znearestall17 1 QC1.74 [0.95, 2.06]1.71-0.23 [-1.29, 1.28]2.12 [1.31, 2.43]35% [14%, 67%]59%82%-1.11-0.842026-08-09 → 2026-08-30
tmin12Zbilinear30d17 1 QC1.28 [0.89, 1.46]1.24-0.24 [-1.10, 0.83]1.50 [1.12, 1.67]35% [24%, 60%]82%100%-0.55-0.332026-08-09 → 2026-08-30
tmin12Zbilinear90d17 1 QC1.28 [0.65, 1.47]1.24-0.24 [-1.15, 0.86]1.50 [0.81, 1.66]35% [25%, 75%]82%100%-0.55-0.332026-08-09 → 2026-08-30
tmin12Zbilinear365d17 1 QC1.28 [0.63, 1.48]1.24-0.24 [-1.12, 1.03]1.50 [0.81, 1.69]35% [25%, 75%]82%100%-0.55-0.332026-08-09 → 2026-08-30
tmin12Zbilinearall17 1 QC1.28 [0.65, 1.49]1.24-0.24 [-1.15, 0.95]1.50 [0.88, 1.68]35% [23%, 67%]82%100%-0.55-0.332026-08-09 → 2026-08-30
tmin12Znearest30d17 1 QC1.58 [1.05, 2.14]1.60-0.48 [-1.73, 1.03]1.91 [1.36, 2.41]29% [12%, 56%]65%82%-0.91-0.732026-08-09 → 2026-08-30
tmin12Znearest90d17 1 QC1.58 [0.77, 2.32]1.60-0.48 [-1.99, 1.05]1.91 [1.11, 2.51]29% [8%, 75%]65%82%-0.91-0.732026-08-09 → 2026-08-30
tmin12Znearest365d17 1 QC1.58 [0.76, 2.30]1.60-0.48 [-1.91, 1.14]1.91 [1.10, 2.47]29% [7%, 75%]65%82%-0.91-0.732026-08-09 → 2026-08-30
tmin12Znearestall17 1 QC1.58 [0.77, 2.45]1.60-0.48 [-2.14, 1.12]1.91 [1.17, 2.58]29% [0%, 67%]65%82%-0.91-0.732026-08-09 → 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 8, 00Z bilinear tmax+20+100-10-202026-08-09: -4.52 °F2026-08-15: -2.61 °F2026-08-16: -4.05 °F2026-08-17: -7.2 °F2026-08-18: -4.97 °F2026-08-19: -4.37 °F2026-08-20: -3.08 °F2026-08-21: -4.78 °F2026-08-22: -4.37 °F2026-08-23: -7.26 °F2026-08-24: -7.02 °F2026-08-25: -6.63 °F2026-08-26: -10.11 °F2026-08-27: -8.02 °F2026-08-28: +1.95 °F2026-08-29: -7.63 °F2026-08-30: -2.78 °F2026-08-092026-08-30°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 (22 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.78
2026-08-29-7.63
2026-08-28+1.95
2026-08-27-8.02
2026-08-26-10.11
2026-08-25-6.63
2026-08-24-7.02
2026-08-23-7.26
2026-08-22-4.37
2026-08-21-4.78
2026-08-20-3.08
2026-08-19-4.37
2026-08-18-4.97
2026-08-17-7.20
2026-08-16-4.05
2026-08-15-2.61
2026-08-14—
2026-08-13—
2026-08-12—
2026-08-11—
2026-08-10—
2026-08-09-4.52

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at KSFO, lead day 8-20 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: 5 days-6 to -4 °F: 6 days-4 to -2 °F: 3 days-2 to 0 °F: 0 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| 4.78 · P90 |e| 7.78 °F-200+20 °Fn = 17 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
-8.00-6.005
-6.00-4.006
-4.00-2.003
-2.00+0.000
+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
2026-08175.37 -5.14

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-09 → 2026-08-30 17
ECMWF IFS HRES2026-08-09 → 2026-08-30 17
ECMWF IFS HRES2026-08-09 → 2026-08-30 17
ECMWF IFS HRES2026-08-09 → 2026-08-30 17

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 17 +0.66 [-1.47, 1.43] no
NCEP GFS 17 +0.97 [0.34, 1.61] yes
GraphCast (IFS init) 17 -0.73 [-2.11, -0.03] yes
Persistence (baseline) 17 +1.61 [0.89, 2.39] yes

Cite this page

ShortCastCheck, KSFO ifs_hres lead 8, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSFO/model/ifs_hres/lead/8/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSFO (San Francisco Intl), model ifs_hres, lead day 8. 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/8/

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