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

All stations (mean of daily station errors) · ECMWF AIFS Single · lead day 3

ALL · 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, 2 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 2 QC3.60 [3.44, 3.80]0.56-3.04 [-3.27, -2.81]4.21 [4.02, 4.41]12% [10%, 13%]25%43%+0.00+0.552026-08-04 → 2026-08-30
tmax00Zbilinear90d27 2 QC3.60 [3.43, 3.80]0.56-3.04 [-3.29, -2.79]4.21 [4.01, 4.41]12% [10%, 13%]25%43%+0.00+0.552026-08-04 → 2026-08-30
tmax00Zbilinear365d27 2 QC3.60 [3.43, 3.82]0.56-3.04 [-3.31, -2.75]4.21 [4.01, 4.44]12% [10%, 13%]25%43%+0.00+0.552026-08-04 → 2026-08-30
tmax00Zbilinearall27 2 QC3.60 [3.40, 3.83]0.56-3.04 [-3.31, -2.79]4.21 [3.98, 4.45]12% [10%, 14%]25%43%+0.00+0.552026-08-04 → 2026-08-30
tmax00Znearest30d27 2 QC3.65 [3.47, 3.85]0.56-2.97 [-3.21, -2.74]4.27 [4.06, 4.49]12% [10%, 14%]27%42%-0.01+0.552026-08-04 → 2026-08-30
tmax00Znearest90d27 2 QC3.65 [3.46, 3.85]0.56-2.97 [-3.23, -2.72]4.27 [4.05, 4.50]12% [10%, 14%]27%42%-0.01+0.552026-08-04 → 2026-08-30
tmax00Znearest365d27 2 QC3.65 [3.45, 3.88]0.56-2.97 [-3.26, -2.69]4.27 [4.04, 4.53]12% [9%, 14%]27%42%-0.01+0.552026-08-04 → 2026-08-30
tmax00Znearestall27 2 QC3.65 [3.45, 3.88]0.56-2.97 [-3.25, -2.72]4.27 [4.02, 4.54]12% [10%, 14%]27%42%-0.01+0.552026-08-04 → 2026-08-30
tmax12Zbilinear30d27 2 QC3.69 [3.52, 3.89]0.50-3.25 [-3.49, -3.07]4.30 [4.14, 4.48]13% [11%, 15%]25%40%-0.02+0.602026-08-04 → 2026-08-30
tmax12Zbilinear90d27 2 QC3.69 [3.52, 3.89]0.50-3.25 [-3.50, -3.05]4.30 [4.12, 4.48]13% [11%, 15%]25%40%-0.02+0.602026-08-04 → 2026-08-30
tmax12Zbilinear365d27 2 QC3.69 [3.51, 3.92]0.50-3.25 [-3.51, -3.04]4.30 [4.12, 4.49]13% [10%, 15%]25%40%-0.02+0.602026-08-04 → 2026-08-30
tmax12Zbilinearall27 2 QC3.69 [3.50, 3.93]0.50-3.25 [-3.54, -3.06]4.30 [4.12, 4.51]13% [10%, 15%]25%40%-0.02+0.602026-08-04 → 2026-08-30
tmax12Znearest30d27 2 QC3.74 [3.56, 3.94]0.51-3.18 [-3.45, -2.99]4.36 [4.19, 4.55]13% [11%, 15%]26%40%-0.03+0.592026-08-04 → 2026-08-30
tmax12Znearest90d27 2 QC3.74 [3.56, 3.95]0.51-3.18 [-3.45, -2.97]4.36 [4.19, 4.55]13% [11%, 16%]26%40%-0.03+0.592026-08-04 → 2026-08-30
tmax12Znearest365d27 2 QC3.74 [3.56, 3.97]0.51-3.18 [-3.46, -2.97]4.36 [4.18, 4.58]13% [11%, 16%]26%40%-0.03+0.592026-08-04 → 2026-08-30
tmax12Znearestall27 2 QC3.74 [3.55, 3.98]0.51-3.18 [-3.50, -2.97]4.36 [4.17, 4.58]13% [11%, 16%]26%40%-0.03+0.592026-08-04 → 2026-08-30
tmin00Zbilinear30d27 2 QC2.37 [2.17, 2.57]0.49+0.39 [0.14, 0.62]3.07 [2.76, 3.32]28% [22%, 33%]52%69%+0.25+0.522026-08-04 → 2026-08-30
tmin00Zbilinear90d27 2 QC2.37 [2.16, 2.59]0.49+0.39 [0.11, 0.65]3.07 [2.77, 3.35]28% [22%, 34%]52%69%+0.25+0.522026-08-04 → 2026-08-30
tmin00Zbilinear365d27 2 QC2.37 [2.13, 2.61]0.49+0.39 [0.09, 0.65]3.07 [2.72, 3.37]28% [22%, 33%]52%69%+0.25+0.522026-08-04 → 2026-08-30
tmin00Zbilinearall27 2 QC2.37 [2.15, 2.62]0.49+0.39 [0.10, 0.64]3.07 [2.76, 3.37]28% [22%, 34%]52%69%+0.25+0.522026-08-04 → 2026-08-30
tmin00Znearest30d27 2 QC2.45 [2.23, 2.66]0.51+0.37 [0.10, 0.61]3.18 [2.87, 3.44]26% [22%, 31%]51%70%+0.22+0.502026-08-04 → 2026-08-30
tmin00Znearest90d27 2 QC2.45 [2.22, 2.69]0.51+0.37 [0.06, 0.63]3.18 [2.87, 3.46]26% [21%, 33%]51%70%+0.22+0.502026-08-04 → 2026-08-30
tmin00Znearest365d27 2 QC2.45 [2.20, 2.70]0.51+0.37 [0.03, 0.63]3.18 [2.82, 3.48]26% [21%, 32%]51%70%+0.22+0.502026-08-04 → 2026-08-30
tmin00Znearestall27 2 QC2.45 [2.22, 2.72]0.51+0.37 [0.05, 0.62]3.18 [2.86, 3.51]26% [21%, 33%]51%70%+0.22+0.502026-08-04 → 2026-08-30
tmin12Zbilinear30d27 2 QC2.31 [2.12, 2.51]0.45+0.30 [0.08, 0.52]3.00 [2.72, 3.26]29% [26%, 32%]54%71%+0.26+0.562026-08-04 → 2026-08-30
tmin12Zbilinear90d27 2 QC2.31 [2.12, 2.53]0.45+0.30 [0.06, 0.54]3.00 [2.72, 3.28]29% [25%, 33%]54%71%+0.26+0.562026-08-04 → 2026-08-30
tmin12Zbilinear365d27 2 QC2.31 [2.09, 2.54]0.45+0.30 [0.07, 0.56]3.00 [2.67, 3.29]29% [25%, 33%]54%71%+0.26+0.562026-08-04 → 2026-08-30
tmin12Zbilinearall27 2 QC2.31 [2.11, 2.54]0.45+0.30 [0.05, 0.55]3.00 [2.71, 3.29]29% [25%, 33%]54%71%+0.26+0.562026-08-04 → 2026-08-30
tmin12Znearest30d27 2 QC2.39 [2.18, 2.59]0.45+0.27 [0.05, 0.49]3.12 [2.82, 3.36]29% [25%, 33%]52%70%+0.24+0.562026-08-04 → 2026-08-30
tmin12Znearest90d27 2 QC2.39 [2.17, 2.61]0.45+0.27 [0.04, 0.52]3.12 [2.82, 3.39]29% [25%, 34%]52%70%+0.24+0.562026-08-04 → 2026-08-30
tmin12Znearest365d27 2 QC2.39 [2.15, 2.62]0.45+0.27 [0.03, 0.53]3.12 [2.77, 3.39]29% [25%, 34%]52%70%+0.24+0.562026-08-04 → 2026-08-30
tmin12Znearestall27 2 QC2.39 [2.17, 2.62]0.45+0.27 [0.01, 0.50]3.12 [2.81, 3.40]29% [25%, 34%]52%70%+0.24+0.562026-08-04 → 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 ALL, lead day 3, 00Z bilinear tmax+5+2.50-2.5-52026-08-04: -2.65 °F2026-08-05: -4.33 °F2026-08-06: -2.9 °F2026-08-07: -3.38 °F2026-08-08: -2.76 °F2026-08-09: -3.2 °F2026-08-10: -2.33 °F2026-08-11: -2.74 °F2026-08-12: -3.94 °F2026-08-13: -2.92 °F2026-08-14: -3.44 °F2026-08-15: -2.18 °F2026-08-16: -2.16 °F2026-08-17: -2.32 °F2026-08-18: -2.8 °F2026-08-19: -3.51 °F2026-08-20: -2.25 °F2026-08-21: -2.92 °F2026-08-22: -2.69 °F2026-08-23: -4.07 °F2026-08-24: -4.42 °F2026-08-25: -2.46 °F2026-08-26: -3.21 °F2026-08-27: -3.69 °F2026-08-28: -3.74 °F2026-08-29: -3.14 °F2026-08-30: -2.01 °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
2026-08-30-2.01
2026-08-29-3.14
2026-08-28-3.74
2026-08-27-3.69
2026-08-26-3.21
2026-08-25-2.46
2026-08-24-4.42
2026-08-23-4.07
2026-08-22-2.69
2026-08-21-2.92
2026-08-20-2.25
2026-08-19-3.51
2026-08-18-2.80
2026-08-17-2.32
2026-08-16-2.16
2026-08-15-2.18
2026-08-14-3.44
2026-08-13-2.92
2026-08-12-3.94
2026-08-11-2.74
2026-08-10-2.33
2026-08-09-3.20
2026-08-08-2.76
2026-08-07-3.38
2026-08-06-2.90
2026-08-05-4.33
2026-08-04-2.65

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at ALL, lead day 3-5 to -4.5 °F: 0 days-4.5 to -4 °F: 3 days-4 to -3.5 °F: 4 days-3.5 to -3 °F: 5 days-3 to -2.5 °F: 8 days-2.5 to -2 °F: 7 days-2 to -1.5 °F: 0 days-1.5 to -1 °F: 0 days-1 to -0.5 °F: 0 days-0.5 to 0 °F: 0 days0 to 0.5 °F: 0 days0.5 to 1 °F: 0 days1 to 1.5 °F: 0 days1.5 to 2 °F: 0 days2 to 2.5 °F: 0 days2.5 to 3 °F: 0 days3 to 3.5 °F: 0 days3.5 to 4 °F: 0 days4 to 4.5 °F: 0 days4.5 to 5 °F: 0 daysdashed: P50 |e| 2.92 · P90 |e| 4 °F-50+5 °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
-5.00-4.500
-4.50-4.003
-4.00-3.504
-3.50-3.005
-3.00-2.508
-2.50-2.007
-2.00-1.500
-1.50-1.000
-1.00-0.500
-0.50+0.000
+0.00+0.500
+0.50+1.000
+1.00+1.500
+1.50+2.000
+2.00+2.500
+2.50+3.000
+3.00+3.500
+3.50+4.000
+4.00+4.500
+4.50+5.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08273.04 -3.04

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 +0.40 [0.14, 0.60] yes
GraphCast (IFS init) 25 -1.48 [-1.81, -1.24] yes
ECMWF IFS HRES 22 +0.03 [-0.18, 0.26] no
Persistence (baseline) 27 -0.01 [-0.55, 0.40] no

Cite this page

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

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: ALL (All stations (mean of daily station errors)), 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/ALL/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