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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 5

ALL · aifs_single · lead 5

Target day = initialization date + 5 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
tmax00Zbilinear30d25 2 QC3.90 [3.69, 4.10]0.72-3.22 [-3.53, -2.94]4.66 [4.41, 4.89]11% [9%, 13%]25%40%+0.01+0.522026-08-06 → 2026-08-30
tmax00Zbilinear90d25 2 QC3.90 [3.67, 4.11]0.72-3.22 [-3.53, -2.90]4.66 [4.37, 4.91]11% [9%, 13%]25%40%+0.01+0.522026-08-06 → 2026-08-30
tmax00Zbilinear365d25 2 QC3.90 [3.65, 4.14]0.72-3.22 [-3.54, -2.90]4.66 [4.35, 4.92]11% [9%, 12%]25%40%+0.01+0.522026-08-06 → 2026-08-30
tmax00Zbilinearall25 2 QC3.90 [3.66, 4.14]0.72-3.22 [-3.55, -2.89]4.66 [4.36, 4.93]11% [9%, 13%]25%40%+0.01+0.522026-08-06 → 2026-08-30
tmax00Znearest30d25 2 QC3.94 [3.67, 4.18]0.72-3.16 [-3.46, -2.88]4.73 [4.43, 5.01]12% [10%, 14%]24%42%-0.00+0.522026-08-06 → 2026-08-30
tmax00Znearest90d25 2 QC3.94 [3.65, 4.19]0.72-3.16 [-3.47, -2.84]4.73 [4.39, 5.04]12% [10%, 14%]24%42%-0.00+0.522026-08-06 → 2026-08-30
tmax00Znearest365d25 2 QC3.94 [3.63, 4.19]0.72-3.16 [-3.48, -2.84]4.73 [4.36, 5.03]12% [9%, 14%]24%42%-0.00+0.522026-08-06 → 2026-08-30
tmax00Znearestall25 2 QC3.94 [3.63, 4.22]0.72-3.16 [-3.49, -2.82]4.73 [4.35, 5.05]12% [9%, 14%]24%42%-0.00+0.522026-08-06 → 2026-08-30
tmax12Zbilinear30d24 2 QC3.85 [3.71, 3.99]0.61-3.35 [-3.66, -3.05]4.54 [4.38, 4.70]11% [9%, 15%]26%38%+0.02+0.602026-08-06 → 2026-08-30
tmax12Zbilinear90d24 2 QC3.85 [3.70, 4.01]0.61-3.35 [-3.70, -3.02]4.54 [4.38, 4.73]11% [9%, 16%]26%38%+0.02+0.602026-08-06 → 2026-08-30
tmax12Zbilinear365d24 2 QC3.85 [3.70, 4.01]0.61-3.35 [-3.68, -3.01]4.54 [4.36, 4.69]11% [9%, 16%]26%38%+0.02+0.602026-08-06 → 2026-08-30
tmax12Zbilinearall24 2 QC3.85 [3.71, 4.02]0.61-3.35 [-3.69, -3.02]4.54 [4.37, 4.72]11% [9%, 16%]26%38%+0.02+0.602026-08-06 → 2026-08-30
tmax12Znearest30d24 2 QC3.90 [3.71, 4.08]0.60-3.28 [-3.58, -3.00]4.61 [4.41, 4.82]13% [11%, 14%]24%39%+0.00+0.602026-08-06 → 2026-08-30
tmax12Znearest90d24 2 QC3.90 [3.70, 4.11]0.60-3.28 [-3.60, -2.98]4.61 [4.40, 4.86]13% [11%, 14%]24%39%+0.00+0.602026-08-06 → 2026-08-30
tmax12Znearest365d24 2 QC3.90 [3.70, 4.08]0.60-3.28 [-3.58, -2.96]4.61 [4.37, 4.82]13% [11%, 15%]24%39%+0.00+0.602026-08-06 → 2026-08-30
tmax12Znearestall24 2 QC3.90 [3.70, 4.11]0.60-3.28 [-3.59, -2.98]4.61 [4.39, 4.85]13% [11%, 15%]24%39%+0.00+0.602026-08-06 → 2026-08-30
tmin00Zbilinear30d25 2 QC2.51 [2.20, 2.84]0.67+0.42 [0.08, 0.76]3.28 [2.90, 3.67]29% [24%, 34%]51%68%+0.20+0.272026-08-06 → 2026-08-30
tmin00Zbilinear90d25 2 QC2.51 [2.19, 2.87]0.67+0.42 [0.06, 0.79]3.28 [2.87, 3.70]29% [24%, 35%]51%68%+0.20+0.272026-08-06 → 2026-08-30
tmin00Zbilinear365d25 2 QC2.51 [2.17, 2.90]0.67+0.42 [-0.01, 0.82]3.28 [2.85, 3.73]29% [24%, 35%]51%68%+0.20+0.272026-08-06 → 2026-08-30
tmin00Zbilinearall25 2 QC2.51 [2.17, 2.91]0.67+0.42 [0.01, 0.80]3.28 [2.84, 3.75]29% [23%, 35%]51%68%+0.20+0.272026-08-06 → 2026-08-30
tmin00Znearest30d25 2 QC2.58 [2.24, 2.94]0.67+0.40 [0.06, 0.74]3.39 [2.99, 3.77]29% [22%, 35%]50%66%+0.18+0.262026-08-06 → 2026-08-30
tmin00Znearest90d25 2 QC2.58 [2.22, 2.96]0.67+0.40 [0.02, 0.77]3.39 [2.95, 3.81]29% [22%, 36%]50%66%+0.18+0.262026-08-06 → 2026-08-30
tmin00Znearest365d25 2 QC2.58 [2.20, 3.01]0.67+0.40 [-0.05, 0.81]3.39 [2.93, 3.84]29% [21%, 36%]50%66%+0.18+0.262026-08-06 → 2026-08-30
tmin00Znearestall25 2 QC2.58 [2.20, 3.01]0.67+0.40 [-0.02, 0.78]3.39 [2.93, 3.85]29% [21%, 36%]50%66%+0.18+0.262026-08-06 → 2026-08-30
tmin12Zbilinear30d24 2 QC2.44 [2.18, 2.68]0.72+0.21 [-0.14, 0.57]3.15 [2.79, 3.46]28% [25%, 31%]52%67%+0.22+0.182026-08-06 → 2026-08-30
tmin12Zbilinear90d24 2 QC2.44 [2.16, 2.70]0.72+0.21 [-0.16, 0.60]3.15 [2.77, 3.49]28% [25%, 32%]52%67%+0.22+0.182026-08-06 → 2026-08-30
tmin12Zbilinear365d24 2 QC2.44 [2.15, 2.72]0.72+0.21 [-0.16, 0.64]3.15 [2.76, 3.51]28% [25%, 32%]52%67%+0.22+0.182026-08-06 → 2026-08-30
tmin12Zbilinearall24 2 QC2.44 [2.14, 2.73]0.72+0.21 [-0.18, 0.62]3.15 [2.75, 3.52]28% [25%, 32%]52%67%+0.22+0.182026-08-06 → 2026-08-30
tmin12Znearest30d24 2 QC2.51 [2.22, 2.78]0.72+0.19 [-0.15, 0.55]3.25 [2.88, 3.56]26% [23%, 30%]51%67%+0.20+0.182026-08-06 → 2026-08-30
tmin12Znearest90d24 2 QC2.51 [2.19, 2.79]0.72+0.19 [-0.18, 0.58]3.25 [2.85, 3.58]26% [23%, 31%]51%67%+0.20+0.182026-08-06 → 2026-08-30
tmin12Znearest365d24 2 QC2.51 [2.18, 2.82]0.72+0.19 [-0.19, 0.61]3.25 [2.83, 3.60]26% [23%, 31%]51%67%+0.20+0.182026-08-06 → 2026-08-30
tmin12Znearestall24 2 QC2.51 [2.18, 2.82]0.72+0.19 [-0.21, 0.60]3.25 [2.82, 3.62]26% [23%, 31%]51%67%+0.20+0.182026-08-06 → 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 5, 00Z bilinear tmax+5+2.50-2.5-52026-08-06: -3.33 °F2026-08-07: -3.99 °F2026-08-08: -4.14 °F2026-08-09: -3.01 °F2026-08-10: -2.04 °F2026-08-11: -3.55 °F2026-08-12: -4.65 °F2026-08-13: -2.48 °F2026-08-14: -3.31 °F2026-08-15: -2.44 °F2026-08-16: -2.23 °F2026-08-17: -1.86 °F2026-08-18: -3.27 °F2026-08-19: -4.14 °F2026-08-20: -3.46 °F2026-08-21: -2.25 °F2026-08-22: -1.83 °F2026-08-23: -4.13 °F2026-08-24: -3.76 °F2026-08-25: -3.37 °F2026-08-26: -3.55 °F2026-08-27: -4.1 °F2026-08-28: -3.87 °F2026-08-29: -3.9 °F2026-08-30: -1.85 °F2026-08-062026-08-30°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 (25 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.85
2026-08-29-3.90
2026-08-28-3.87
2026-08-27-4.10
2026-08-26-3.55
2026-08-25-3.37
2026-08-24-3.76
2026-08-23-4.13
2026-08-22-1.83
2026-08-21-2.25
2026-08-20-3.46
2026-08-19-4.14
2026-08-18-3.27
2026-08-17-1.86
2026-08-16-2.23
2026-08-15-2.44
2026-08-14-3.31
2026-08-13-2.48
2026-08-12-4.65
2026-08-11-3.55
2026-08-10-2.04
2026-08-09-3.01
2026-08-08-4.14
2026-08-07-3.99
2026-08-06-3.33

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at ALL, lead day 5-5 to -4.5 °F: 1 day-4.5 to -4 °F: 4 days-4 to -3.5 °F: 6 days-3.5 to -3 °F: 6 days-3 to -2.5 °F: 0 days-2.5 to -2 °F: 5 days-2 to -1.5 °F: 3 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| 3.37 · P90 |e| 4.14 °F-50+5 °Fn = 25 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
-5.00-4.501
-4.50-4.004
-4.00-3.506
-3.50-3.006
-3.00-2.500
-2.50-2.005
-2.00-1.503
-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
2026-08253.22 -3.22

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-06 → 2026-08-30 25
ECMWF AIFS Single2026-08-06 → 2026-08-30 25
ECMWF AIFS Single2026-08-06 → 2026-08-30 24
ECMWF AIFS Single2026-08-06 → 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 25 +0.35 [-0.16, 0.86] no
GraphCast (IFS init) 25 -1.51 [-1.92, -1.02] yes
ECMWF IFS HRES 18 +0.22 [-0.08, 0.39] no
Persistence (baseline) 25 -0.03 [-0.58, 0.45] no

Cite this page

ShortCastCheck, ALL aifs_single lead 5, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/ALL/model/aifs_single/lead/5/

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 5. 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/5/

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