Philadelphia Intl · Persistence (baseline) · lead day 1
KPHL · 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, 1 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 | 3.13 [2.43, 3.77] | 3.14 | +0.07 [-0.67, 0.80] | 4.05 [3.14, 4.96] | 30% [20%, 43%] | 47% | 57% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 00Z | bilinear | 90d | 90 1 QC | 4.01 [3.32, 4.73] | 4.01 | -0.08 [-0.72, 0.57] | 5.12 [4.33, 5.90] | 21% [12%, 30%] | 39% | 50% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 00Z | bilinear | 365d | 365 1 QC | 5.76 [5.06, 6.53] | 5.76 | -0.03 [-0.50, 0.44] | 7.70 [6.79, 8.63] | 16% [12%, 21%] | 28% | 38% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 00Z | bilinear | all | 972 1 QC | 5.65 [5.27, 6.08] | 5.65 | -0.04 [-0.35, 0.24] | 7.45 [6.96, 7.96] | 16% [14%, 19%] | 27% | 38% | — | — | 2024-01-02 → 2026-08-30 |
| tmax | 00Z | nearest | 30d | 30 1 QC | 3.13 [2.43, 3.77] | 3.14 | +0.07 [-0.67, 0.80] | 4.05 [3.14, 4.96] | 30% [20%, 43%] | 47% | 57% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 00Z | nearest | 90d | 90 1 QC | 4.01 [3.32, 4.73] | 4.01 | -0.08 [-0.72, 0.57] | 5.12 [4.33, 5.90] | 21% [12%, 30%] | 39% | 50% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 00Z | nearest | 365d | 365 1 QC | 5.76 [5.06, 6.53] | 5.76 | -0.03 [-0.50, 0.44] | 7.70 [6.79, 8.63] | 16% [12%, 21%] | 28% | 38% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 00Z | nearest | all | 972 1 QC | 5.65 [5.27, 6.08] | 5.65 | -0.04 [-0.35, 0.24] | 7.45 [6.96, 7.96] | 16% [14%, 19%] | 27% | 38% | — | — | 2024-01-02 → 2026-08-30 |
| tmax | 12Z | bilinear | 30d | 30 1 QC | 3.13 [2.43, 3.77] | 3.14 | +0.07 [-0.67, 0.80] | 4.05 [3.14, 4.96] | 30% [20%, 43%] | 47% | 57% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 12Z | bilinear | 90d | 90 1 QC | 4.01 [3.32, 4.73] | 4.01 | -0.08 [-0.72, 0.57] | 5.12 [4.33, 5.90] | 21% [12%, 30%] | 39% | 50% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 12Z | bilinear | 365d | 365 1 QC | 5.76 [5.06, 6.53] | 5.76 | -0.03 [-0.50, 0.44] | 7.70 [6.79, 8.63] | 16% [12%, 21%] | 28% | 38% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 12Z | bilinear | all | 972 1 QC | 5.65 [5.27, 6.08] | 5.65 | -0.04 [-0.35, 0.24] | 7.45 [6.96, 7.96] | 16% [14%, 19%] | 27% | 38% | — | — | 2024-01-02 → 2026-08-30 |
| tmax | 12Z | nearest | 30d | 30 1 QC | 3.13 [2.43, 3.77] | 3.14 | +0.07 [-0.67, 0.80] | 4.05 [3.14, 4.96] | 30% [20%, 43%] | 47% | 57% | — | — | 2026-08-01 → 2026-08-30 |
| tmax | 12Z | nearest | 90d | 90 1 QC | 4.01 [3.32, 4.73] | 4.01 | -0.08 [-0.72, 0.57] | 5.12 [4.33, 5.90] | 21% [12%, 30%] | 39% | 50% | — | — | 2026-06-02 → 2026-08-30 |
| tmax | 12Z | nearest | 365d | 365 1 QC | 5.76 [5.06, 6.53] | 5.76 | -0.03 [-0.50, 0.44] | 7.70 [6.79, 8.63] | 16% [12%, 21%] | 28% | 38% | — | — | 2025-08-31 → 2026-08-30 |
| tmax | 12Z | nearest | all | 972 1 QC | 5.65 [5.27, 6.08] | 5.65 | -0.04 [-0.35, 0.24] | 7.45 [6.96, 7.96] | 16% [14%, 19%] | 27% | 38% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 00Z | bilinear | 30d | 30 1 QC | 2.70 [2.10, 3.37] | 2.72 | +0.23 [-0.43, 0.90] | 3.21 [2.63, 3.76] | 23% [7%, 40%] | 47% | 70% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 00Z | bilinear | 90d | 90 1 QC | 3.22 [2.74, 3.79] | 3.23 | -0.09 [-0.56, 0.36] | 4.07 [3.47, 4.74] | 29% [20%, 36%] | 46% | 59% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 00Z | bilinear | 365d | 365 1 QC | 4.22 [3.78, 4.73] | 4.23 | -0.02 [-0.37, 0.33] | 5.53 [4.87, 6.24] | 19% [14%, 24%] | 32% | 45% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 00Z | bilinear | all | 972 1 QC | 4.06 [3.80, 4.34] | 4.06 | -0.03 [-0.24, 0.18] | 5.27 [4.92, 5.64] | 20% [17%, 23%] | 33% | 47% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 00Z | nearest | 30d | 30 1 QC | 2.70 [2.10, 3.37] | 2.72 | +0.23 [-0.43, 0.90] | 3.21 [2.63, 3.76] | 23% [7%, 40%] | 47% | 70% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 00Z | nearest | 90d | 90 1 QC | 3.22 [2.74, 3.79] | 3.23 | -0.09 [-0.56, 0.36] | 4.07 [3.47, 4.74] | 29% [20%, 36%] | 46% | 59% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 00Z | nearest | 365d | 365 1 QC | 4.22 [3.78, 4.73] | 4.23 | -0.02 [-0.37, 0.33] | 5.53 [4.87, 6.24] | 19% [14%, 24%] | 32% | 45% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 00Z | nearest | all | 972 1 QC | 4.06 [3.80, 4.34] | 4.06 | -0.03 [-0.24, 0.18] | 5.27 [4.92, 5.64] | 20% [17%, 23%] | 33% | 47% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 12Z | bilinear | 30d | 30 1 QC | 2.70 [2.10, 3.37] | 2.72 | +0.23 [-0.43, 0.90] | 3.21 [2.63, 3.76] | 23% [7%, 40%] | 47% | 70% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 12Z | bilinear | 90d | 90 1 QC | 3.22 [2.74, 3.79] | 3.23 | -0.09 [-0.56, 0.36] | 4.07 [3.47, 4.74] | 29% [20%, 36%] | 46% | 59% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 12Z | bilinear | 365d | 365 1 QC | 4.22 [3.78, 4.73] | 4.23 | -0.02 [-0.37, 0.33] | 5.53 [4.87, 6.24] | 19% [14%, 24%] | 32% | 45% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 12Z | bilinear | all | 972 1 QC | 4.06 [3.80, 4.34] | 4.06 | -0.03 [-0.24, 0.18] | 5.27 [4.92, 5.64] | 20% [17%, 23%] | 33% | 47% | — | — | 2024-01-02 → 2026-08-30 |
| tmin | 12Z | nearest | 30d | 30 1 QC | 2.70 [2.10, 3.37] | 2.72 | +0.23 [-0.43, 0.90] | 3.21 [2.63, 3.76] | 23% [7%, 40%] | 47% | 70% | — | — | 2026-08-01 → 2026-08-30 |
| tmin | 12Z | nearest | 90d | 90 1 QC | 3.22 [2.74, 3.79] | 3.23 | -0.09 [-0.56, 0.36] | 4.07 [3.47, 4.74] | 29% [20%, 36%] | 46% | 59% | — | — | 2026-06-02 → 2026-08-30 |
| tmin | 12Z | nearest | 365d | 365 1 QC | 4.22 [3.78, 4.73] | 4.23 | -0.02 [-0.37, 0.33] | 5.53 [4.87, 6.24] | 19% [14%, 24%] | 32% | 45% | — | — | 2025-08-31 → 2026-08-30 |
| tmin | 12Z | nearest | all | 972 1 QC | 4.06 [3.80, 4.34] | 4.06 | -0.03 [-0.24, 0.18] | 5.27 [4.92, 5.64] | 20% [17%, 23%] | 33% | 47% | — | — | 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 KPHL, 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 KPHL, lead day 1: no scored days yet.
Availability
| Model | Scored period | Days | Coverage |
|---|---|---|---|
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 972 | |
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 972 | |
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 972 | |
| Persistence (baseline) | 2024-01-02 → 2026-08-30 | 972 |
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 | +0.80 [-0.57, 1.71] | no |
| Aurora (GFS init) | 1 | -1.52 [-1.52, -1.52] | yes |
| Aurora (IFS init) | 2 | +0.81 [0.16, 1.46] | yes |
| FourCastNet v2 (GFS init) | 1 | +0.28 [0.28, 0.28] | yes |
| FourCastNet v2 (IFS init) | 2 | +2.29 [-0.25, 4.83] | no |
| NCEP GFS | 29 | +0.33 [-1.25, 2.14] | no |
| GraphCast (GFS init) | 1 | -1.35 [-1.35, -1.35] | yes |
| GraphCast (IFS init) | 27 | -1.97 [-3.39, -0.87] | yes |
| ECMWF IFS HRES | 23 | -1.00 [-1.89, -0.25] | yes |
| Pangu-Weather (GFS init) | 1 | +2.46 [2.46, 2.46] | yes |
| Pangu-Weather (IFS init) | 2 | +3.34 [1.69, 4.99] | yes |
Cite this page
ShortCastCheck, KPHL persistence lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KPHL/model/persistence/lead/1/
LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHL (Philadelphia 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/KPHL/model/persistence/lead/1/
Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)