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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 6

ALL · aifs_single · lead 6

Target day = initialization date + 6 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
tmax00Zbilinear30d24 2 QC4.17 [3.83, 4.51]0.70-3.56 [-3.86, -3.24]5.10 [4.78, 5.37]13% [10%, 16%]27%39%-0.06+0.512026-08-07 → 2026-08-30
tmax00Zbilinear90d24 2 QC4.17 [3.80, 4.54]0.70-3.56 [-3.86, -3.21]5.10 [4.75, 5.40]13% [10%, 16%]27%39%-0.06+0.512026-08-07 → 2026-08-30
tmax00Zbilinear365d24 2 QC4.17 [3.79, 4.59]0.70-3.56 [-3.89, -3.22]5.10 [4.71, 5.42]13% [9%, 16%]27%39%-0.06+0.512026-08-07 → 2026-08-30
tmax00Zbilinearall24 2 QC4.17 [3.78, 4.58]0.70-3.56 [-3.91, -3.18]5.10 [4.68, 5.44]13% [10%, 16%]27%39%-0.06+0.512026-08-07 → 2026-08-30
tmax00Znearest30d24 2 QC4.20 [3.81, 4.57]0.71-3.50 [-3.83, -3.16]5.15 [4.80, 5.45]12% [10%, 15%]25%40%-0.06+0.512026-08-07 → 2026-08-30
tmax00Znearest90d24 2 QC4.20 [3.79, 4.59]0.71-3.50 [-3.84, -3.13]5.15 [4.78, 5.48]12% [9%, 15%]25%40%-0.06+0.512026-08-07 → 2026-08-30
tmax00Znearest365d24 2 QC4.20 [3.76, 4.61]0.71-3.50 [-3.88, -3.13]5.15 [4.75, 5.49]12% [9%, 15%]25%40%-0.06+0.512026-08-07 → 2026-08-30
tmax00Znearestall24 2 QC4.20 [3.76, 4.63]0.71-3.50 [-3.88, -3.10]5.15 [4.73, 5.51]12% [9%, 15%]25%40%-0.06+0.512026-08-07 → 2026-08-30
tmax12Zbilinear30d24 2 QC4.16 [3.88, 4.47]0.72-3.52 [-3.80, -3.25]4.99 [4.60, 5.36]12% [9%, 14%]23%38%-0.05+0.502026-08-07 → 2026-08-30
tmax12Zbilinear90d24 2 QC4.16 [3.86, 4.50]0.72-3.52 [-3.79, -3.24]4.99 [4.57, 5.41]12% [9%, 15%]23%38%-0.05+0.502026-08-07 → 2026-08-30
tmax12Zbilinear365d24 2 QC4.16 [3.84, 4.55]0.72-3.52 [-3.80, -3.22]4.99 [4.54, 5.43]12% [8%, 15%]23%38%-0.05+0.502026-08-07 → 2026-08-30
tmax12Zbilinearall24 2 QC4.16 [3.83, 4.55]0.72-3.52 [-3.81, -3.23]4.99 [4.55, 5.45]12% [9%, 14%]23%38%-0.05+0.502026-08-07 → 2026-08-30
tmax12Znearest30d24 2 QC4.20 [3.87, 4.53]0.73-3.45 [-3.72, -3.19]5.05 [4.62, 5.47]11% [9%, 12%]24%38%-0.06+0.492026-08-07 → 2026-08-30
tmax12Znearest90d24 2 QC4.20 [3.84, 4.57]0.73-3.45 [-3.71, -3.16]5.05 [4.58, 5.53]11% [9%, 13%]24%38%-0.06+0.492026-08-07 → 2026-08-30
tmax12Znearest365d24 2 QC4.20 [3.81, 4.59]0.73-3.45 [-3.75, -3.15]5.05 [4.54, 5.54]11% [9%, 13%]24%38%-0.06+0.492026-08-07 → 2026-08-30
tmax12Znearestall24 2 QC4.20 [3.81, 4.59]0.73-3.45 [-3.76, -3.16]5.05 [4.54, 5.55]11% [9%, 12%]24%38%-0.06+0.492026-08-07 → 2026-08-30
tmin00Zbilinear30d24 2 QC2.65 [2.34, 2.94]0.66+0.40 [0.10, 0.68]3.42 [3.04, 3.79]26% [22%, 31%]50%65%+0.23+0.372026-08-07 → 2026-08-30
tmin00Zbilinear90d24 2 QC2.65 [2.32, 2.96]0.66+0.40 [0.05, 0.73]3.42 [2.99, 3.81]26% [22%, 32%]50%65%+0.23+0.372026-08-07 → 2026-08-30
tmin00Zbilinear365d24 2 QC2.65 [2.30, 2.99]0.66+0.40 [0.03, 0.73]3.42 [2.97, 3.84]26% [21%, 32%]50%65%+0.23+0.372026-08-07 → 2026-08-30
tmin00Zbilinearall24 2 QC2.65 [2.30, 2.98]0.66+0.40 [0.02, 0.73]3.42 [2.96, 3.85]26% [21%, 32%]50%65%+0.23+0.372026-08-07 → 2026-08-30
tmin00Znearest30d24 2 QC2.74 [2.39, 3.07]0.66+0.38 [0.07, 0.66]3.54 [3.13, 3.91]23% [19%, 28%]48%64%+0.20+0.382026-08-07 → 2026-08-30
tmin00Znearest90d24 2 QC2.74 [2.37, 3.08]0.66+0.38 [0.03, 0.71]3.54 [3.08, 3.93]23% [18%, 29%]48%64%+0.20+0.382026-08-07 → 2026-08-30
tmin00Znearest365d24 2 QC2.74 [2.34, 3.13]0.66+0.38 [-0.01, 0.72]3.54 [3.06, 3.98]23% [18%, 29%]48%64%+0.20+0.382026-08-07 → 2026-08-30
tmin00Znearestall24 2 QC2.74 [2.32, 3.12]0.66+0.38 [-0.02, 0.71]3.54 [3.05, 3.97]23% [18%, 29%]48%64%+0.20+0.382026-08-07 → 2026-08-30
tmin12Zbilinear30d24 2 QC2.57 [2.37, 2.78]0.70+0.22 [-0.14, 0.61]3.36 [3.06, 3.64]27% [24%, 31%]50%67%+0.25+0.342026-08-07 → 2026-08-30
tmin12Zbilinear90d24 2 QC2.57 [2.36, 2.79]0.70+0.22 [-0.19, 0.64]3.36 [3.04, 3.67]27% [24%, 32%]50%67%+0.25+0.342026-08-07 → 2026-08-30
tmin12Zbilinear365d24 2 QC2.57 [2.35, 2.83]0.70+0.22 [-0.20, 0.68]3.36 [3.04, 3.71]27% [24%, 32%]50%67%+0.25+0.342026-08-07 → 2026-08-30
tmin12Zbilinearall24 2 QC2.57 [2.35, 2.83]0.70+0.22 [-0.23, 0.68]3.36 [3.03, 3.70]27% [24%, 32%]50%67%+0.25+0.342026-08-07 → 2026-08-30
tmin12Znearest30d24 2 QC2.64 [2.40, 2.87]0.71+0.19 [-0.17, 0.58]3.46 [3.13, 3.75]27% [24%, 33%]48%66%+0.23+0.342026-08-07 → 2026-08-30
tmin12Znearest90d24 2 QC2.64 [2.38, 2.89]0.71+0.19 [-0.22, 0.62]3.46 [3.11, 3.77]27% [24%, 34%]48%66%+0.23+0.342026-08-07 → 2026-08-30
tmin12Znearest365d24 2 QC2.64 [2.37, 2.92]0.71+0.19 [-0.23, 0.67]3.46 [3.10, 3.82]27% [23%, 34%]48%66%+0.23+0.342026-08-07 → 2026-08-30
tmin12Znearestall24 2 QC2.64 [2.37, 2.94]0.71+0.19 [-0.25, 0.66]3.46 [3.10, 3.80]27% [24%, 34%]48%66%+0.23+0.342026-08-07 → 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 6, 00Z bilinear tmax+10+50-5-102026-08-07: -3.71 °F2026-08-08: -3.9 °F2026-08-09: -3.1 °F2026-08-10: -2.92 °F2026-08-11: -3.67 °F2026-08-12: -4.67 °F2026-08-13: -2.64 °F2026-08-14: -3.55 °F2026-08-15: -2.2 °F2026-08-16: -2.49 °F2026-08-17: -2.63 °F2026-08-18: -4.64 °F2026-08-19: -3.7 °F2026-08-20: -3.91 °F2026-08-21: -4.58 °F2026-08-22: -2.47 °F2026-08-23: -3.81 °F2026-08-24: -5.33 °F2026-08-25: -3.12 °F2026-08-26: -3.95 °F2026-08-27: -5.16 °F2026-08-28: -3.65 °F2026-08-29: -2.71 °F2026-08-30: -2.84 °F2026-08-072026-08-30°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 (24 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.84
2026-08-29-2.71
2026-08-28-3.65
2026-08-27-5.16
2026-08-26-3.95
2026-08-25-3.12
2026-08-24-5.33
2026-08-23-3.81
2026-08-22-2.47
2026-08-21-4.58
2026-08-20-3.91
2026-08-19-3.70
2026-08-18-4.64
2026-08-17-2.63
2026-08-16-2.49
2026-08-15-2.20
2026-08-14-3.55
2026-08-13-2.64
2026-08-12-4.67
2026-08-11-3.67
2026-08-10-2.92
2026-08-09-3.10
2026-08-08-3.90
2026-08-07-3.71

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at ALL, lead day 6-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 2 days-5 to -4 °F: 3 days-4 to -3 °F: 11 days-3 to -2 °F: 8 days-2 to -1 °F: 0 days-1 to 0 °F: 0 days0 to 1 °F: 0 days1 to 2 °F: 0 days2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 3.66 · P90 |e| 4.66 °F-100+10 °Fn = 24 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
-10.00-9.000
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.002
-5.00-4.003
-4.00-3.0011
-3.00-2.008
-2.00-1.000
-1.00+0.000
+0.00+1.000
+1.00+2.000
+2.00+3.000
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08243.56 -3.56

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24
ECMWF AIFS Single2026-08-07 → 2026-08-30 24

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 24 +0.47 [0.07, 0.88] yes
GraphCast (IFS init) 24 -1.49 [-1.83, -1.16] yes
ECMWF IFS HRES 19 +0.11 [-0.51, 0.59] no
Persistence (baseline) 24 +0.22 [-0.42, 0.80] no

Cite this page

ShortCastCheck, ALL aifs_single lead 6, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/ALL/model/aifs_single/lead/6/

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 6. 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/6/

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