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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 1

ALL · aifs_single · 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, 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
tmax00Zbilinear30d29 2 QC3.46 [3.32, 3.61]0.45-3.08 [-3.29, -2.91]4.03 [3.90, 4.17]14% [12%, 15%]28%44%-0.29+0.392026-08-02 → 2026-08-30
tmax00Zbilinear90d29 2 QC3.46 [3.31, 3.64]0.45-3.08 [-3.33, -2.89]4.03 [3.88, 4.18]14% [12%, 16%]28%44%-0.29+0.392026-08-02 → 2026-08-30
tmax00Zbilinear365d29 2 QC3.46 [3.31, 3.65]0.45-3.08 [-3.35, -2.89]4.03 [3.90, 4.19]14% [12%, 16%]28%44%-0.29+0.392026-08-02 → 2026-08-30
tmax00Zbilinearall29 2 QC3.46 [3.30, 3.64]0.45-3.08 [-3.33, -2.88]4.03 [3.90, 4.19]14% [12%, 16%]28%44%-0.29+0.392026-08-02 → 2026-08-30
tmax00Znearest30d29 2 QC3.49 [3.36, 3.63]0.47-3.00 [-3.23, -2.80]4.08 [3.94, 4.21]13% [11%, 15%]28%45%-0.30+0.372026-08-02 → 2026-08-30
tmax00Znearest90d29 2 QC3.49 [3.35, 3.65]0.47-3.00 [-3.29, -2.78]4.08 [3.94, 4.25]13% [11%, 16%]28%45%-0.30+0.372026-08-02 → 2026-08-30
tmax00Znearest365d29 2 QC3.49 [3.35, 3.68]0.47-3.00 [-3.31, -2.77]4.08 [3.94, 4.26]13% [11%, 15%]28%45%-0.30+0.372026-08-02 → 2026-08-30
tmax00Znearestall29 2 QC3.49 [3.35, 3.66]0.47-3.00 [-3.28, -2.75]4.08 [3.94, 4.25]13% [11%, 16%]28%45%-0.30+0.372026-08-02 → 2026-08-30
tmax12Zbilinear30d29 2 QC3.52 [3.37, 3.67]0.43-3.14 [-3.37, -2.96]4.10 [3.95, 4.25]13% [10%, 15%]27%43%-0.31+0.422026-08-02 → 2026-08-30
tmax12Zbilinear90d29 2 QC3.52 [3.36, 3.70]0.43-3.14 [-3.42, -2.95]4.10 [3.94, 4.28]13% [10%, 15%]27%43%-0.31+0.422026-08-02 → 2026-08-30
tmax12Zbilinear365d29 2 QC3.52 [3.36, 3.72]0.43-3.14 [-3.44, -2.95]4.10 [3.93, 4.29]13% [10%, 15%]27%43%-0.31+0.422026-08-02 → 2026-08-30
tmax12Zbilinearall29 2 QC3.52 [3.37, 3.70]0.43-3.14 [-3.40, -2.94]4.10 [3.95, 4.28]13% [10%, 15%]27%43%-0.31+0.422026-08-02 → 2026-08-30
tmax12Znearest30d29 2 QC3.56 [3.42, 3.71]0.45-3.05 [-3.30, -2.83]4.16 [4.01, 4.32]14% [12%, 16%]29%42%-0.32+0.392026-08-02 → 2026-08-30
tmax12Znearest90d29 2 QC3.56 [3.41, 3.74]0.45-3.05 [-3.37, -2.83]4.16 [4.00, 4.34]14% [12%, 16%]29%42%-0.32+0.392026-08-02 → 2026-08-30
tmax12Znearest365d29 2 QC3.56 [3.41, 3.75]0.45-3.05 [-3.40, -2.82]4.16 [4.00, 4.36]14% [11%, 16%]29%42%-0.32+0.392026-08-02 → 2026-08-30
tmax12Znearestall29 2 QC3.56 [3.42, 3.75]0.45-3.05 [-3.34, -2.81]4.16 [4.00, 4.36]14% [11%, 17%]29%42%-0.32+0.392026-08-02 → 2026-08-30
tmin00Zbilinear30d29 2 QC2.23 [2.02, 2.42]0.39+0.24 [0.04, 0.41]2.89 [2.60, 3.13]31% [29%, 33%]55%72%+0.05+0.482026-08-02 → 2026-08-30
tmin00Zbilinear90d29 2 QC2.23 [2.03, 2.44]0.39+0.24 [-0.01, 0.41]2.89 [2.61, 3.17]31% [28%, 34%]55%72%+0.05+0.482026-08-02 → 2026-08-30
tmin00Zbilinear365d29 2 QC2.23 [1.99, 2.45]0.39+0.24 [-0.03, 0.41]2.89 [2.56, 3.17]31% [28%, 34%]55%72%+0.05+0.482026-08-02 → 2026-08-30
tmin00Zbilinearall29 2 QC2.23 [2.01, 2.45]0.39+0.24 [-0.01, 0.40]2.89 [2.58, 3.19]31% [28%, 34%]55%72%+0.05+0.482026-08-02 → 2026-08-30
tmin00Znearest30d29 2 QC2.33 [2.09, 2.53]0.41+0.21 [-0.00, 0.40]3.04 [2.71, 3.30]30% [27%, 33%]54%70%+0.01+0.462026-08-02 → 2026-08-30
tmin00Znearest90d29 2 QC2.33 [2.10, 2.56]0.41+0.21 [-0.04, 0.40]3.04 [2.72, 3.35]30% [26%, 34%]54%70%+0.01+0.462026-08-02 → 2026-08-30
tmin00Znearest365d29 2 QC2.33 [2.05, 2.57]0.41+0.21 [-0.09, 0.40]3.04 [2.66, 3.34]30% [26%, 34%]54%70%+0.01+0.462026-08-02 → 2026-08-30
tmin00Znearestall29 2 QC2.33 [2.08, 2.57]0.41+0.21 [-0.04, 0.39]3.04 [2.70, 3.37]30% [26%, 34%]54%70%+0.01+0.462026-08-02 → 2026-08-30
tmin12Zbilinear30d29 2 QC2.15 [1.98, 2.31]0.39+0.16 [-0.02, 0.32]2.80 [2.53, 3.01]33% [30%, 36%]57%73%+0.08+0.492026-08-02 → 2026-08-30
tmin12Zbilinear90d29 2 QC2.15 [1.98, 2.34]0.39+0.16 [-0.08, 0.32]2.80 [2.53, 3.06]33% [29%, 36%]57%73%+0.08+0.492026-08-02 → 2026-08-30
tmin12Zbilinear365d29 2 QC2.15 [1.95, 2.34]0.39+0.16 [-0.11, 0.33]2.80 [2.48, 3.05]33% [29%, 36%]57%73%+0.08+0.492026-08-02 → 2026-08-30
tmin12Zbilinearall29 2 QC2.15 [1.96, 2.36]0.39+0.16 [-0.08, 0.32]2.80 [2.51, 3.07]33% [29%, 36%]57%73%+0.08+0.492026-08-02 → 2026-08-30
tmin12Znearest30d29 2 QC2.25 [2.04, 2.44]0.41+0.14 [-0.07, 0.30]2.94 [2.64, 3.19]31% [29%, 32%]55%73%+0.04+0.462026-08-02 → 2026-08-30
tmin12Znearest90d29 2 QC2.25 [2.04, 2.47]0.41+0.14 [-0.13, 0.31]2.94 [2.64, 3.23]31% [28%, 33%]55%73%+0.04+0.462026-08-02 → 2026-08-30
tmin12Znearest365d29 2 QC2.25 [2.01, 2.47]0.41+0.14 [-0.15, 0.32]2.94 [2.59, 3.23]31% [28%, 33%]55%73%+0.04+0.462026-08-02 → 2026-08-30
tmin12Znearestall29 2 QC2.25 [2.02, 2.48]0.41+0.14 [-0.12, 0.30]2.94 [2.63, 3.25]31% [28%, 33%]55%73%+0.04+0.462026-08-02 → 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 ECMWF AIFS Single at ALL, lead day 1, 00Z bilinear tmax+5+2.50-2.5-52026-08-02: -2.96 °F2026-08-03: -4.17 °F2026-08-04: -2.68 °F2026-08-05: -3.48 °F2026-08-06: -2.85 °F2026-08-07: -3.24 °F2026-08-08: -2.49 °F2026-08-09: -2.49 °F2026-08-10: -2.51 °F2026-08-11: -2.29 °F2026-08-12: -3.86 °F2026-08-13: -2.88 °F2026-08-14: -3.65 °F2026-08-15: -2.39 °F2026-08-16: -2.36 °F2026-08-17: -3.22 °F2026-08-18: -2.77 °F2026-08-19: -3.04 °F2026-08-20: -3.43 °F2026-08-21: -2.92 °F2026-08-22: -2.58 °F2026-08-23: -3.67 °F2026-08-24: -3.52 °F2026-08-25: -2.73 °F2026-08-26: -2.88 °F2026-08-27: -3.9 °F2026-08-28: -3.87 °F2026-08-29: -3.57 °F2026-08-30: -3.07 °F2026-08-022026-08-30°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 (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-3.07
2026-08-29-3.57
2026-08-28-3.87
2026-08-27-3.90
2026-08-26-2.88
2026-08-25-2.73
2026-08-24-3.52
2026-08-23-3.67
2026-08-22-2.58
2026-08-21-2.92
2026-08-20-3.43
2026-08-19-3.04
2026-08-18-2.77
2026-08-17-3.22
2026-08-16-2.36
2026-08-15-2.39
2026-08-14-3.65
2026-08-13-2.88
2026-08-12-3.86
2026-08-11-2.29
2026-08-10-2.51
2026-08-09-2.49
2026-08-08-2.49
2026-08-07-3.24
2026-08-06-2.85
2026-08-05-3.48
2026-08-04-2.68
2026-08-03-4.17
2026-08-02-2.96

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at ALL, lead day 1-5 to -4.5 °F: 0 days-4.5 to -4 °F: 1 day-4 to -3.5 °F: 7 days-3.5 to -3 °F: 6 days-3 to -2.5 °F: 10 days-2.5 to -2 °F: 5 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| 2.96 · P90 |e| 3.86 °F-50+5 °Fn = 29 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
-4.50-4.001
-4.00-3.507
-3.50-3.006
-3.00-2.5010
-2.50-2.005
-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
2026-08293.08 -3.08

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29
ECMWF AIFS Single2026-08-02 → 2026-08-30 29

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
Aurora (GFS init) 1 -3.21 [-3.21, -3.21] yes
Aurora (IFS init) 2 -1.80 [-1.99, -1.61] yes
FourCastNet v2 (GFS init) 1 -0.82 [-0.82, -0.82] yes
FourCastNet v2 (IFS init) 2 -0.53 [-0.59, -0.46] yes
NCEP GFS 29 +0.53 [0.39, 0.66] yes
GraphCast (GFS init) 1 -2.87 [-2.87, -2.87] yes
GraphCast (IFS init) 27 -1.50 [-1.65, -1.39] yes
ECMWF IFS HRES 23 -0.10 [-0.20, 0.00] no
Pangu-Weather (GFS init) 1 -0.43 [-0.43, -0.43] yes
Pangu-Weather (IFS init) 2 -0.61 [-0.67, -0.55] yes
Persistence (baseline) 29 +0.77 [0.55, 0.96] yes

Cite this page

ShortCastCheck, ALL aifs_single lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/ALL/model/aifs_single/lead/1/

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 1. 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/1/

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