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

All stations (mean of daily station errors) · ECMWF IFS HRES · lead day 4

ALL · ifs_hres · lead 4

Target day = initialization date + 4 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, ifs-gpid161, 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
tmax00Zbilinear30d20 2 QC3.58 [3.35, 3.71]0.73-2.50 [-2.82, -2.07]4.35 [4.06, 4.50]13% [12%, 14%]30%47%+0.06+0.442026-08-05 → 2026-08-30
tmax00Zbilinear90d20 2 QC3.58 [3.31, 3.71]0.73-2.50 [-2.83, -2.05]4.35 [4.01, 4.49]13% [11%, 14%]30%47%+0.06+0.442026-08-05 → 2026-08-30
tmax00Zbilinear365d20 2 QC3.58 [3.28, 3.70]0.73-2.50 [-2.83, -2.03]4.35 [3.99, 4.50]13% [11%, 14%]30%47%+0.06+0.442026-08-05 → 2026-08-30
tmax00Zbilinearall20 2 QC3.58 [3.12, 3.70]0.73-2.50 [-2.81, -2.01]4.35 [3.82, 4.49]13% [11%, 14%]30%47%+0.06+0.442026-08-05 → 2026-08-30
tmax00Znearest30d20 2 QC3.74 [3.46, 3.88]0.76-2.50 [-2.92, -1.96]4.55 [4.16, 4.75]12% [11%, 14%]30%46%+0.02+0.412026-08-05 → 2026-08-30
tmax00Znearest90d20 2 QC3.74 [3.37, 3.88]0.76-2.50 [-2.94, -1.92]4.55 [4.04, 4.75]12% [11%, 13%]30%46%+0.02+0.412026-08-05 → 2026-08-30
tmax00Znearest365d20 2 QC3.74 [3.34, 3.88]0.76-2.50 [-2.94, -1.90]4.55 [4.02, 4.75]12% [11%, 14%]30%46%+0.02+0.412026-08-05 → 2026-08-30
tmax00Znearestall20 2 QC3.74 [3.22, 3.87]0.76-2.50 [-2.93, -1.90]4.55 [3.88, 4.76]12% [11%, 14%]30%46%+0.02+0.412026-08-05 → 2026-08-30
tmax12Zbilinear30d21 2 QC3.63 [3.38, 3.88]0.53-2.75 [-3.08, -2.49]4.33 [4.10, 4.55]12% [8%, 17%]26%45%+0.05+0.602026-08-05 → 2026-08-30
tmax12Zbilinear90d21 2 QC3.63 [3.33, 3.87]0.53-2.75 [-3.08, -2.45]4.33 [4.03, 4.55]12% [8%, 18%]26%45%+0.05+0.602026-08-05 → 2026-08-30
tmax12Zbilinear365d21 2 QC3.63 [3.35, 3.93]0.53-2.75 [-3.08, -2.42]4.33 [4.05, 4.59]12% [8%, 18%]26%45%+0.05+0.602026-08-05 → 2026-08-30
tmax12Zbilinearall21 2 QC3.63 [3.20, 3.89]0.53-2.75 [-3.06, -2.46]4.33 [3.94, 4.59]12% [8%, 19%]26%45%+0.05+0.602026-08-05 → 2026-08-30
tmax12Znearest30d21 2 QC3.77 [3.48, 3.98]0.56-2.78 [-3.16, -2.43]4.55 [4.28, 4.72]15% [11%, 20%]28%43%+0.01+0.582026-08-05 → 2026-08-30
tmax12Znearest90d21 2 QC3.77 [3.42, 3.97]0.56-2.78 [-3.17, -2.40]4.55 [4.22, 4.73]15% [12%, 22%]28%43%+0.01+0.582026-08-05 → 2026-08-30
tmax12Znearest365d21 2 QC3.77 [3.45, 4.00]0.56-2.78 [-3.16, -2.36]4.55 [4.21, 4.73]15% [11%, 22%]28%43%+0.01+0.582026-08-05 → 2026-08-30
tmax12Znearestall21 2 QC3.77 [3.32, 3.98]0.56-2.78 [-3.15, -2.40]4.55 [4.08, 4.74]15% [11%, 22%]28%43%+0.01+0.582026-08-05 → 2026-08-30
tmin00Zbilinear30d20 2 QC2.84 [2.64, 3.03]0.63+1.71 [1.34, 2.08]3.72 [3.46, 4.03]26% [23%, 29%]46%63%+0.06-0.022026-08-05 → 2026-08-30
tmin00Zbilinear90d20 2 QC2.84 [2.64, 3.05]0.63+1.71 [1.32, 2.12]3.72 [3.46, 4.19]26% [23%, 29%]46%63%+0.06-0.022026-08-05 → 2026-08-30
tmin00Zbilinear365d20 2 QC2.84 [2.61, 3.05]0.63+1.71 [1.27, 2.12]3.72 [3.42, 4.13]26% [23%, 30%]46%63%+0.06-0.022026-08-05 → 2026-08-30
tmin00Zbilinearall20 2 QC2.84 [2.62, 3.05]0.63+1.71 [1.26, 2.11]3.72 [3.41, 4.15]26% [23%, 30%]46%63%+0.06-0.022026-08-05 → 2026-08-30
tmin00Znearest30d20 2 QC2.96 [2.70, 3.18]0.65+1.75 [1.36, 2.15]3.90 [3.60, 4.21]27% [22%, 31%]45%61%+0.02-0.052026-08-05 → 2026-08-30
tmin00Znearest90d20 2 QC2.96 [2.67, 3.20]0.65+1.75 [1.34, 2.18]3.90 [3.60, 4.36]27% [22%, 31%]45%61%+0.02-0.052026-08-05 → 2026-08-30
tmin00Znearest365d20 2 QC2.96 [2.63, 3.20]0.65+1.75 [1.31, 2.19]3.90 [3.54, 4.32]27% [22%, 31%]45%61%+0.02-0.052026-08-05 → 2026-08-30
tmin00Znearestall20 2 QC2.96 [2.66, 3.20]0.65+1.75 [1.30, 2.16]3.90 [3.56, 4.36]27% [22%, 31%]45%61%+0.02-0.052026-08-05 → 2026-08-30
tmin12Zbilinear30d21 2 QC2.75 [2.53, 3.01]0.66+1.43 [1.00, 1.78]3.65 [3.31, 4.10]28% [25%, 31%]48%63%+0.10-0.022026-08-05 → 2026-08-30
tmin12Zbilinear90d21 2 QC2.75 [2.51, 3.09]0.66+1.43 [0.94, 1.82]3.65 [3.32, 4.25]28% [25%, 32%]48%63%+0.10-0.022026-08-05 → 2026-08-30
tmin12Zbilinear365d21 2 QC2.75 [2.47, 3.08]0.66+1.43 [0.93, 1.82]3.65 [3.27, 4.24]28% [24%, 32%]48%63%+0.10-0.022026-08-05 → 2026-08-30
tmin12Zbilinearall21 2 QC2.75 [2.50, 3.09]0.66+1.43 [0.93, 1.87]3.65 [3.27, 4.35]28% [25%, 32%]48%63%+0.10-0.022026-08-05 → 2026-08-30
tmin12Znearest30d21 2 QC2.84 [2.56, 3.13]0.68+1.46 [1.02, 1.85]3.79 [3.38, 4.26]28% [25%, 31%]47%63%+0.07-0.052026-08-05 → 2026-08-30
tmin12Znearest90d21 2 QC2.84 [2.54, 3.21]0.68+1.46 [0.93, 1.89]3.79 [3.38, 4.43]28% [25%, 31%]47%63%+0.07-0.052026-08-05 → 2026-08-30
tmin12Znearest365d21 2 QC2.84 [2.50, 3.21]0.68+1.46 [0.94, 1.89]3.79 [3.33, 4.43]28% [25%, 31%]47%63%+0.07-0.052026-08-05 → 2026-08-30
tmin12Znearestall21 2 QC2.84 [2.51, 3.21]0.68+1.46 [0.93, 1.92]3.79 [3.34, 4.45]28% [25%, 32%]47%63%+0.07-0.052026-08-05 → 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 IFS HRES at ALL, lead day 4, 00Z bilinear tmax+5+2.50-2.5-52026-08-05: -2.47 °F2026-08-11: -1.73 °F2026-08-12: -3.03 °F2026-08-13: -2.3 °F2026-08-14: -1.29 °F2026-08-16: -0.28 °F2026-08-17: -2.9 °F2026-08-18: -2.58 °F2026-08-19: -2.45 °F2026-08-20: -4.42 °F2026-08-21: -1.53 °F2026-08-22: -2.16 °F2026-08-23: -3.12 °F2026-08-24: -3.17 °F2026-08-25: -2.16 °F2026-08-26: -3.14 °F2026-08-27: -3.24 °F2026-08-28: -4.16 °F2026-08-29: -1.77 °F2026-08-30: -2.05 °F2026-08-052026-08-30°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 (26 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-2.05
2026-08-29-1.77
2026-08-28-4.16
2026-08-27-3.24
2026-08-26-3.14
2026-08-25-2.16
2026-08-24-3.17
2026-08-23-3.12
2026-08-22-2.16
2026-08-21-1.53
2026-08-20-4.42
2026-08-19-2.45
2026-08-18-2.58
2026-08-17-2.90
2026-08-16-0.28
2026-08-15—
2026-08-14-1.29
2026-08-13-2.30
2026-08-12-3.03
2026-08-11-1.73
2026-08-10—
2026-08-09—
2026-08-08—
2026-08-07—
2026-08-06—
2026-08-05-2.47

Error distribution

Distribution of the signed daily error in °F for ECMWF IFS HRES at ALL, lead day 4-5 to -4.5 °F: 0 days-4.5 to -4 °F: 2 days-4 to -3.5 °F: 0 days-3.5 to -3 °F: 5 days-3 to -2.5 °F: 2 days-2.5 to -2 °F: 6 days-2 to -1.5 °F: 3 days-1.5 to -1 °F: 1 day-1 to -0.5 °F: 0 days-0.5 to 0 °F: 1 day0 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| 2.46 · P90 |e| 3.33 °F-50+5 °Fn = 20 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
-4.50-4.002
-4.00-3.500
-3.50-3.005
-3.00-2.502
-2.50-2.006
-2.00-1.503
-1.50-1.001
-1.00-0.500
-0.50+0.001
+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
2026-08202.50 -2.50

Availability

ModelScored period DaysCoverage
ECMWF IFS HRES2026-08-05 → 2026-08-30 20
ECMWF IFS HRES2026-08-05 → 2026-08-30 20
ECMWF IFS HRES2026-08-05 → 2026-08-30 21
ECMWF IFS HRES2026-08-05 → 2026-08-30 21

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means ECMWF IFS HRES has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 20 -0.17 [-0.53, 0.01] no
NCEP GFS 20 +0.28 [0.00, 0.48] yes
GraphCast (IFS init) 19 -1.81 [-2.14, -1.40] yes
Persistence (baseline) 20 -0.22 [-1.01, 0.06] no

Cite this page

ShortCastCheck, ALL ifs_hres lead 4, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/ALL/model/ifs_hres/lead/4/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: ALL (All stations (mean of daily station errors)), model ifs_hres, lead day 4. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/ALL/model/ifs_hres/lead/4/

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