San Francisco Intl · Persistence (baseline) · lead day 1
KSFO · persistence · 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, obs, starting 2024-01-01 — days before that ran a different version of the model and are excluded rather than silently pooled. Of the scored days, 2 carry a QC flag on the observation.
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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.
| Variable | Init | Method | Window | n | MAE °F | MAE debiased | Bias °F | RMSE °F | ±1 °F | ±2 °F | ±3 °F | Skill | Skill, debiased | Period |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| tmax | 00Z | bilinear | 30d | 30 1 QC | 3.03 [1.93, 4.30] | 3.03 | +0.03 [-0.70, 0.67] | 3.87 [2.36, 5.20] | 30% [17%, 43%] | 50% | 60% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 00Z | bilinear | 90d | 90 1 QC | 3.58 [2.51, 4.68] | 3.58 | +0.00 [-0.50, 0.50] | 5.19 [3.42, 6.75] | 31% [19%, 44%] | 44% | 60% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 00Z | bilinear | 365d | 365 1 QC | 3.67 [3.23, 4.13] | 3.68 | +0.04 [-0.27, 0.32] | 4.95 [4.30, 5.56] | 28% [23%, 33%] | 40% | 54% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 00Z | bilinear | all | 967 2 QC | 3.64 [3.36, 3.92] | 3.64 | -0.01 [-0.19, 0.16] | 4.94 [4.56, 5.35] | 28% [25%, 31%] | 42% | 56% | — | — | 2024-01-02 → 2026-08-30 |
| tmax | 00Z | nearest | 30d | 30 1 QC | 3.03 [1.93, 4.30] | 3.03 | +0.03 [-0.70, 0.67] | 3.87 [2.36, 5.20] | 30% [17%, 43%] | 50% | 60% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 00Z | nearest | 90d | 90 1 QC | 3.58 [2.51, 4.68] | 3.58 | +0.00 [-0.50, 0.50] | 5.19 [3.42, 6.75] | 31% [19%, 44%] | 44% | 60% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 00Z | nearest | 365d | 365 1 QC | 3.67 [3.23, 4.13] | 3.68 | +0.04 [-0.27, 0.32] | 4.95 [4.30, 5.56] | 28% [23%, 33%] | 40% | 54% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 00Z | nearest | all | 967 2 QC | 3.64 [3.36, 3.92] | 3.64 | -0.01 [-0.19, 0.16] | 4.94 [4.56, 5.35] | 28% [25%, 31%] | 42% | 56% | — | — | 2024-01-02 → 2026-08-30 |
| tmax | 12Z | bilinear | 30d | 30 1 QC | 3.03 [1.93, 4.30] | 3.03 | +0.03 [-0.70, 0.67] | 3.87 [2.36, 5.20] | 30% [17%, 43%] | 50% | 60% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 12Z | bilinear | 90d | 90 1 QC | 3.58 [2.51, 4.68] | 3.58 | +0.00 [-0.50, 0.50] | 5.19 [3.42, 6.75] | 31% [19%, 44%] | 44% | 60% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 12Z | bilinear | 365d | 365 1 QC | 3.67 [3.23, 4.13] | 3.68 | +0.04 [-0.27, 0.32] | 4.95 [4.30, 5.56] | 28% [23%, 33%] | 40% | 54% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 12Z | bilinear | all | 967 2 QC | 3.64 [3.36, 3.92] | 3.64 | -0.01 [-0.19, 0.16] | 4.94 [4.56, 5.35] | 28% [25%, 31%] | 42% | 56% | — | — | 2024-01-02 → 2026-08-30 |
| tmax | 12Z | nearest | 30d | 30 1 QC | 3.03 [1.93, 4.30] | 3.03 | +0.03 [-0.70, 0.67] | 3.87 [2.36, 5.20] | 30% [17%, 43%] | 50% | 60% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 12Z | nearest | 90d | 90 1 QC | 3.58 [2.51, 4.68] | 3.58 | +0.00 [-0.50, 0.50] | 5.19 [3.42, 6.75] | 31% [19%, 44%] | 44% | 60% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 12Z | nearest | 365d | 365 1 QC | 3.67 [3.23, 4.13] | 3.68 | +0.04 [-0.27, 0.32] | 4.95 [4.30, 5.56] | 28% [23%, 33%] | 40% | 54% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 12Z | nearest | all | 967 2 QC | 3.64 [3.36, 3.92] | 3.64 | -0.01 [-0.19, 0.16] | 4.94 [4.56, 5.35] | 28% [25%, 31%] | 42% | 56% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 00Z | bilinear | 30d | 30 1 QC | 0.93 [0.67, 1.30] | 0.93 | +0.00 [-0.20, 0.23] | 1.29 [0.91, 1.66] | 67% [50%, 83%] | 87% | 93% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 00Z | bilinear | 90d | 90 1 QC | 1.16 [0.91, 1.41] | 1.17 | -0.04 [-0.24, 0.14] | 1.60 [1.27, 1.89] | 66% [56%, 76%] | 83% | 90% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 00Z | bilinear | 365d | 365 1 QC | 1.93 [1.69, 2.20] | 1.93 | +0.00 [-0.19, 0.17] | 2.55 [2.26, 2.85] | 44% [38%, 50%] | 59% | 75% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 00Z | bilinear | all | 965 1 QC | 1.96 [1.79, 2.14] | 1.97 | -0.01 [-0.11, 0.10] | 2.67 [2.47, 2.86] | 43% [39%, 47%] | 60% | 75% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 00Z | nearest | 30d | 30 1 QC | 0.93 [0.67, 1.30] | 0.93 | +0.00 [-0.20, 0.23] | 1.29 [0.91, 1.66] | 67% [50%, 83%] | 87% | 93% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 00Z | nearest | 90d | 90 1 QC | 1.16 [0.91, 1.41] | 1.17 | -0.04 [-0.24, 0.14] | 1.60 [1.27, 1.89] | 66% [56%, 76%] | 83% | 90% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 00Z | nearest | 365d | 365 1 QC | 1.93 [1.69, 2.20] | 1.93 | +0.00 [-0.19, 0.17] | 2.55 [2.26, 2.85] | 44% [38%, 50%] | 59% | 75% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 00Z | nearest | all | 965 1 QC | 1.96 [1.79, 2.14] | 1.97 | -0.01 [-0.11, 0.10] | 2.67 [2.47, 2.86] | 43% [39%, 47%] | 60% | 75% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 12Z | bilinear | 30d | 30 1 QC | 0.93 [0.67, 1.30] | 0.93 | +0.00 [-0.20, 0.23] | 1.29 [0.91, 1.66] | 67% [50%, 83%] | 87% | 93% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 12Z | bilinear | 90d | 90 1 QC | 1.16 [0.91, 1.41] | 1.17 | -0.04 [-0.24, 0.14] | 1.60 [1.27, 1.89] | 66% [56%, 76%] | 83% | 90% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 12Z | bilinear | 365d | 365 1 QC | 1.93 [1.69, 2.20] | 1.93 | +0.00 [-0.19, 0.17] | 2.55 [2.26, 2.85] | 44% [38%, 50%] | 59% | 75% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 12Z | bilinear | all | 965 1 QC | 1.96 [1.79, 2.14] | 1.97 | -0.01 [-0.11, 0.10] | 2.67 [2.47, 2.86] | 43% [39%, 47%] | 60% | 75% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 12Z | nearest | 30d | 30 1 QC | 0.93 [0.67, 1.30] | 0.93 | +0.00 [-0.20, 0.23] | 1.29 [0.91, 1.66] | 67% [50%, 83%] | 87% | 93% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 12Z | nearest | 90d | 90 1 QC | 1.16 [0.91, 1.41] | 1.17 | -0.04 [-0.24, 0.14] | 1.60 [1.27, 1.89] | 66% [56%, 76%] | 83% | 90% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 12Z | nearest | 365d | 365 1 QC | 1.93 [1.69, 2.20] | 1.93 | +0.00 [-0.19, 0.17] | 2.55 [2.26, 2.85] | 44% [38%, 50%] | 59% | 75% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 12Z | nearest | all | 965 1 QC | 1.96 [1.79, 2.14] | 1.97 | -0.01 [-0.11, 0.10] | 2.67 [2.47, 2.86] | 43% [39%, 47%] | 60% | 75% | — | — | 2024-01-02 → 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 Persistence (baseline) at KSFO, lead day 1, 00Z bilinear tmax: no scored days yet.
The same series as a table (0 days, newest first) · download CSV
| Climatological day | Error °F |
|---|
Error distribution
Distribution of the signed daily error in °F for Persistence (baseline) at KSFO, lead day 1: no scored days yet.
Availability
| Model | Scored period | Days | Coverage |
|---|---|---|---|
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 967 | |
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 967 | |
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 967 | |
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 967 |
Compared with other models
Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means Persistence (baseline) has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.
| Other model | Common days | MAE difference °F | Distinguishable |
|---|---|---|---|
| ECMWF AIFS Single | 29 | -1.58 [-3.45, 0.35] | no |
| Aurora (GFS init) | 1 | -6.64 [-6.64, -6.64] | yes |
| Aurora (IFS init) | 2 | -5.32 [-8.31, -2.34] | yes |
| FourCastNet v2 (GFS init) | 1 | -1.41 [-1.41, -1.41] | yes |
| FourCastNet v2 (IFS init) | 2 | +0.55 [-2.33, 3.43] | no |
| NCEP GFS | 29 | -1.68 [-3.69, 0.36] | no |
| GraphCast (GFS init) | 1 | -4.64 [-4.64, -4.64] | yes |
| GraphCast (IFS init) | 27 | -2.21 [-3.86, -0.55] | yes |
| ECMWF IFS HRES | 22 | -3.43 [-5.77, -1.22] | yes |
| Pangu-Weather (GFS init) | 1 | -6.64 [-6.64, -6.64] | yes |
| Pangu-Weather (IFS init) | 2 | -3.70 [-6.82, -0.59] | yes |
Cite this page
ShortCastCheck, KSFO persistence lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSFO/model/persistence/lead/1/
LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSFO (San Francisco Intl), model persistence, 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/KSFO/model/persistence/lead/1/
Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)