Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

Phoenix Sky Harbor · ECMWF AIFS Single · lead day 3

KPHX · aifs_single · lead 3

Target day = initialization date + 3 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
tmax00Zbilinear30d27 1 QC3.63 [2.49, 4.85]2.12-3.40 [-4.75, -2.12]4.43 [2.99, 5.79]7% [0%, 15%]33%52%+0.37+0.632026-08-04 → 2026-08-30
tmax00Zbilinear90d27 1 QC3.63 [2.22, 5.41]2.12-3.40 [-5.28, -1.77]4.43 [2.56, 6.24]7% [0%, 15%]33%52%+0.37+0.632026-08-04 → 2026-08-30
tmax00Zbilinear365d27 1 QC3.63 [2.10, 5.66]2.12-3.40 [-5.62, -1.66]4.43 [2.40, 6.58]7% [0%, 15%]33%52%+0.37+0.632026-08-04 → 2026-08-30
tmax00Zbilinearall27 1 QC3.63 [2.18, 5.38]2.12-3.40 [-5.29, -1.79]4.43 [2.49, 6.31]7% [0%, 15%]33%52%+0.37+0.632026-08-04 → 2026-08-30
tmax00Znearest30d27 1 QC3.60 [2.47, 4.82]2.09-3.37 [-4.70, -2.10]4.39 [2.94, 5.78]7% [0%, 15%]33%52%+0.38+0.642026-08-04 → 2026-08-30
tmax00Znearest90d27 1 QC3.60 [2.20, 5.36]2.09-3.37 [-5.28, -1.76]4.39 [2.52, 6.23]7% [0%, 15%]33%52%+0.38+0.642026-08-04 → 2026-08-30
tmax00Znearest365d27 1 QC3.60 [2.09, 5.61]2.09-3.37 [-5.59, -1.67]4.39 [2.35, 6.57]7% [0%, 15%]33%52%+0.38+0.642026-08-04 → 2026-08-30
tmax00Znearestall27 1 QC3.60 [2.13, 5.35]2.09-3.37 [-5.26, -1.79]4.39 [2.44, 6.31]7% [0%, 15%]33%52%+0.38+0.642026-08-04 → 2026-08-30
tmax12Zbilinear30d27 1 QC3.76 [2.73, 4.86]2.26-3.53 [-4.72, -2.32]4.71 [3.36, 6.04]15% [7%, 25%]22%44%+0.35+0.612026-08-04 → 2026-08-30
tmax12Zbilinear90d27 1 QC3.76 [2.39, 5.27]2.26-3.53 [-5.16, -1.86]4.71 [2.79, 6.55]15% [5%, 27%]22%44%+0.35+0.612026-08-04 → 2026-08-30
tmax12Zbilinear365d27 1 QC3.76 [2.27, 5.71]2.26-3.53 [-5.63, -1.73]4.71 [2.65, 6.84]15% [3%, 27%]22%44%+0.35+0.612026-08-04 → 2026-08-30
tmax12Zbilinearall27 1 QC3.76 [2.40, 5.33]2.26-3.53 [-5.24, -1.93]4.71 [2.84, 6.63]15% [0%, 26%]22%44%+0.35+0.612026-08-04 → 2026-08-30
tmax12Znearest30d27 1 QC3.71 [2.69, 4.78]2.25-3.49 [-4.66, -2.30]4.66 [3.31, 6.02]11% [3%, 19%]22%44%+0.36+0.612026-08-04 → 2026-08-30
tmax12Znearest90d27 1 QC3.71 [2.35, 5.24]2.25-3.49 [-5.13, -1.85]4.66 [2.75, 6.53]11% [3%, 20%]22%44%+0.36+0.612026-08-04 → 2026-08-30
tmax12Znearest365d27 1 QC3.71 [2.24, 5.63]2.25-3.49 [-5.57, -1.72]4.66 [2.61, 6.80]11% [0%, 20%]22%44%+0.36+0.612026-08-04 → 2026-08-30
tmax12Znearestall27 1 QC3.71 [2.36, 5.28]2.25-3.49 [-5.18, -1.91]4.66 [2.80, 6.60]11% [0%, 21%]22%44%+0.36+0.612026-08-04 → 2026-08-30
tmin00Zbilinear30d27 1 QC3.65 [2.52, 4.98]3.17-1.85 [-3.38, -0.40]4.49 [3.33, 5.67]19% [4%, 33%]33%48%+0.36+0.442026-08-04 → 2026-08-30
tmin00Zbilinear90d27 1 QC3.65 [2.29, 5.03]3.17-1.85 [-3.64, -0.27]4.49 [3.01, 5.73]19% [0%, 35%]33%48%+0.36+0.442026-08-04 → 2026-08-30
tmin00Zbilinear365d27 1 QC3.65 [2.27, 5.07]3.17-1.85 [-3.93, -0.12]4.49 [3.00, 5.74]19% [0%, 36%]33%48%+0.36+0.442026-08-04 → 2026-08-30
tmin00Zbilinearall27 1 QC3.65 [2.29, 4.92]3.17-1.85 [-3.75, -0.18]4.49 [2.97, 5.62]19% [0%, 36%]33%48%+0.36+0.442026-08-04 → 2026-08-30
tmin00Znearest30d27 1 QC3.71 [2.57, 5.08]3.22-1.91 [-3.45, -0.44]4.54 [3.38, 5.72]19% [4%, 33%]33%48%+0.35+0.432026-08-04 → 2026-08-30
tmin00Znearest90d27 1 QC3.71 [2.31, 5.10]3.22-1.91 [-3.71, -0.32]4.54 [3.03, 5.76]19% [0%, 35%]33%48%+0.35+0.432026-08-04 → 2026-08-30
tmin00Znearest365d27 1 QC3.71 [2.28, 5.14]3.22-1.91 [-4.04, -0.18]4.54 [3.03, 5.76]19% [0%, 36%]33%48%+0.35+0.432026-08-04 → 2026-08-30
tmin00Znearestall27 1 QC3.71 [2.30, 5.01]3.22-1.91 [-3.84, -0.25]4.54 [3.01, 5.67]19% [0%, 36%]33%48%+0.35+0.432026-08-04 → 2026-08-30
tmin12Zbilinear30d27 1 QC3.51 [2.33, 5.00]3.14-1.88 [-3.34, -0.31]4.52 [3.30, 5.76]30% [11%, 46%]41%52%+0.38+0.442026-08-04 → 2026-08-30
tmin12Zbilinear90d27 1 QC3.51 [2.11, 5.05]3.14-1.88 [-3.50, -0.21]4.52 [2.96, 5.84]30% [7%, 50%]41%52%+0.38+0.442026-08-04 → 2026-08-30
tmin12Zbilinear365d27 1 QC3.51 [2.03, 5.14]3.14-1.88 [-3.80, -0.06]4.52 [2.95, 5.85]30% [4%, 50%]41%52%+0.38+0.442026-08-04 → 2026-08-30
tmin12Zbilinearall27 1 QC3.51 [2.07, 4.97]3.14-1.88 [-3.77, -0.07]4.52 [2.89, 5.73]30% [3%, 50%]41%52%+0.38+0.442026-08-04 → 2026-08-30
tmin12Znearest30d27 1 QC3.56 [2.36, 5.04]3.20-1.91 [-3.39, -0.34]4.56 [3.35, 5.80]30% [11%, 46%]41%48%+0.37+0.432026-08-04 → 2026-08-30
tmin12Znearest90d27 1 QC3.56 [2.10, 5.10]3.20-1.91 [-3.58, -0.23]4.56 [2.97, 5.87]30% [7%, 50%]41%48%+0.37+0.432026-08-04 → 2026-08-30
tmin12Znearest365d27 1 QC3.56 [2.05, 5.19]3.20-1.91 [-3.89, -0.07]4.56 [2.98, 5.90]30% [4%, 50%]41%48%+0.37+0.432026-08-04 → 2026-08-30
tmin12Znearestall27 1 QC3.56 [2.07, 5.02]3.20-1.91 [-3.85, -0.10]4.56 [2.90, 5.76]30% [3%, 50%]41%48%+0.37+0.432026-08-04 → 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 KPHX, lead day 3, 00Z bilinear tmax+20+100-10-202026-08-04: +1.13 °F2026-08-05: -1.4 °F2026-08-06: -1.21 °F2026-08-07: -1.71 °F2026-08-08: -3.26 °F2026-08-09: -2.58 °F2026-08-10: -2.99 °F2026-08-11: -4.68 °F2026-08-12: -6.35 °F2026-08-13: -2.86 °F2026-08-14: -2.76 °F2026-08-15: -4.41 °F2026-08-16: -2.3 °F2026-08-17: -0.27 °F2026-08-18: -1.86 °F2026-08-19: -1.34 °F2026-08-20: +1.99 °F2026-08-21: -3.43 °F2026-08-22: -5.35 °F2026-08-23: -8.41 °F2026-08-24: -3.88 °F2026-08-25: -4.11 °F2026-08-26: -4.82 °F2026-08-27: -0.94 °F2026-08-28: -4.13 °F2026-08-29: -9.6 °F2026-08-30: -10.35 °F2026-08-042026-08-30°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 (27 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-10.35
2026-08-29-9.60
2026-08-28-4.13
2026-08-27-0.94
2026-08-26-4.82
2026-08-25-4.11
2026-08-24-3.88
2026-08-23-8.41
2026-08-22-5.35
2026-08-21-3.43
2026-08-20+1.99
2026-08-19-1.34
2026-08-18-1.86
2026-08-17-0.27
2026-08-16-2.30
2026-08-15-4.41
2026-08-14-2.76
2026-08-13-2.86
2026-08-12-6.35
2026-08-11-4.68
2026-08-10-2.99
2026-08-09-2.58
2026-08-08-3.26
2026-08-07-1.71
2026-08-06-1.21
2026-08-05-1.40
2026-08-04+1.13

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KPHX, lead day 3-20 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: 2 days-8 to -6 °F: 1 day-6 to -4 °F: 6 days-4 to -2 °F: 8 days-2 to 0 °F: 7 days0 to 2 °F: 2 days2 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| 2.99 · P90 |e| 7.17 °F-200+20 °Fn = 27 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
-10.00-8.002
-8.00-6.001
-6.00-4.006
-4.00-2.008
-2.00+0.007
+0.00+2.002
+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
2026-08273.63 -3.40

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-04 → 2026-08-30 27
ECMWF AIFS Single2026-08-04 → 2026-08-30 27
ECMWF AIFS Single2026-08-04 → 2026-08-30 27
ECMWF AIFS Single2026-08-04 → 2026-08-30 27

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 27 -0.41 [-1.50, 0.93] no
GraphCast (IFS init) 25 -0.32 [-1.12, 0.30] no
ECMWF IFS HRES 22 +1.02 [-0.40, 2.35] no
Persistence (baseline) 27 -2.14 [-4.83, 0.65] no

Cite this page

ShortCastCheck, KPHX aifs_single lead 3, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KPHX/model/aifs_single/lead/3/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KPHX (Phoenix Sky Harbor), model aifs_single, lead day 3. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KPHX/model/aifs_single/lead/3/

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