Raw model output on the native 0.25° grid — no MOS, no bias correction, no post-processing. Scores understate operational forecast quality. Read the fairness statement →

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

Boston Logan · ECMWF AIFS Single · lead day 0

KBOS · aifs_single · lead 0

Target day = initialization date + 0 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, 1 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 1 QC3.25 [2.86, 3.62]2.15-2.77 [-3.41, -2.14]3.80 [3.40, 4.19]10% [3%, 17%]31%52%——2026-08-01 → 2026-08-30
tmax00Zbilinear90d29 1 QC3.25 [2.87, 3.67]2.15-2.77 [-3.54, -2.03]3.80 [3.40, 4.21]10% [0%, 16%]31%52%——2026-08-01 → 2026-08-30
tmax00Zbilinear365d29 1 QC3.25 [2.80, 3.67]2.15-2.77 [-3.54, -1.95]3.80 [3.34, 4.21]10% [0%, 17%]31%52%——2026-08-01 → 2026-08-30
tmax00Zbilinearall29 1 QC3.25 [2.83, 3.70]2.15-2.77 [-3.59, -2.00]3.80 [3.36, 4.23]10% [0%, 16%]31%52%——2026-08-01 → 2026-08-30
tmax00Znearest30d29 1 QC3.20 [2.78, 3.61]2.10-2.76 [-3.44, -2.10]3.76 [3.33, 4.18]14% [4%, 23%]31%52%——2026-08-01 → 2026-08-30
tmax00Znearest90d29 1 QC3.20 [2.78, 3.68]2.10-2.76 [-3.59, -1.98]3.76 [3.32, 4.22]14% [3%, 23%]31%52%——2026-08-01 → 2026-08-30
tmax00Znearest365d29 1 QC3.20 [2.70, 3.68]2.10-2.76 [-3.54, -1.88]3.76 [3.25, 4.19]14% [0%, 24%]31%52%——2026-08-01 → 2026-08-30
tmax00Znearestall29 1 QC3.20 [2.74, 3.73]2.10-2.76 [-3.61, -1.96]3.76 [3.27, 4.23]14% [3%, 24%]31%52%——2026-08-01 → 2026-08-30
tmin00Zbilinear30d29 1 QC1.30 [1.00, 1.59]1.29-0.07 [-0.80, 0.68]1.67 [1.28, 2.02]52% [37%, 66%]72%93%——2026-08-01 → 2026-08-30
tmin00Zbilinear90d29 1 QC1.30 [1.02, 1.65]1.29-0.07 [-1.03, 0.70]1.67 [1.35, 2.08]52% [35%, 68%]72%93%——2026-08-01 → 2026-08-30
tmin00Zbilinear365d29 1 QC1.30 [1.00, 1.68]1.29-0.07 [-1.18, 0.76]1.67 [1.30, 2.12]52% [33%, 70%]72%93%——2026-08-01 → 2026-08-30
tmin00Zbilinearall29 1 QC1.30 [1.00, 1.68]1.29-0.07 [-1.08, 0.73]1.67 [1.31, 2.09]52% [35%, 69%]72%93%——2026-08-01 → 2026-08-30
tmin00Znearest30d29 1 QC1.27 [1.00, 1.55]1.27+0.19 [-0.53, 0.95]1.66 [1.30, 1.99]52% [41%, 63%]79%93%——2026-08-01 → 2026-08-30
tmin00Znearest90d29 1 QC1.27 [1.01, 1.61]1.27+0.19 [-0.75, 0.97]1.66 [1.32, 2.06]52% [39%, 65%]79%93%——2026-08-01 → 2026-08-30
tmin00Znearest365d29 1 QC1.27 [0.98, 1.65]1.27+0.19 [-0.92, 1.02]1.66 [1.30, 2.09]52% [40%, 67%]79%93%——2026-08-01 → 2026-08-30
tmin00Znearestall29 1 QC1.27 [0.97, 1.61]1.27+0.19 [-0.78, 0.98]1.66 [1.30, 2.04]52% [38%, 64%]79%93%——2026-08-01 → 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 KBOS, lead day 0, 00Z bilinear tmax+10+50-5-102026-08-01: -3.43 °F2026-08-02: -4.1 °F2026-08-03: -2.64 °F2026-08-04: -4.62 °F2026-08-05: -4.07 °F2026-08-06: +0.03 °F2026-08-07: -7.19 °F2026-08-08: -5.52 °F2026-08-09: -2.1 °F2026-08-10: -1.35 °F2026-08-11: -4.56 °F2026-08-12: -1.04 °F2026-08-13: -5.85 °F2026-08-14: -4.07 °F2026-08-15: +1.75 °F2026-08-16: -2.44 °F2026-08-17: -2.85 °F2026-08-18: -0.4 °F2026-08-19: -7.04 °F2026-08-20: -2.71 °F2026-08-21: +1.12 °F2026-08-22: -1.94 °F2026-08-23: +2.23 °F2026-08-24: -6.25 °F2026-08-25: -3.88 °F2026-08-26: +0.44 °F2026-08-27: -5.18 °F2026-08-29: +1.34 °F2026-08-30: -4.08 °F2026-08-012026-08-30°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 (30 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-4.08
2026-08-29+1.34
2026-08-28—
2026-08-27-5.18
2026-08-26+0.44
2026-08-25-3.88
2026-08-24-6.25
2026-08-23+2.23
2026-08-22-1.94
2026-08-21+1.12
2026-08-20-2.71
2026-08-19-7.04
2026-08-18-0.40
2026-08-17-2.85
2026-08-16-2.44
2026-08-15+1.75
2026-08-14-4.07
2026-08-13-5.85
2026-08-12-1.04
2026-08-11-4.56
2026-08-10-1.35
2026-08-09-2.10
2026-08-08-5.52
2026-08-07-7.19
2026-08-06+0.03
2026-08-05-4.07
2026-08-04-4.62
2026-08-03-2.64
2026-08-02-4.10
2026-08-01-3.43

Error distribution

Distribution of the signed daily error in °F for ECMWF AIFS Single at KBOS, lead day 0-10 to -9 °F: 0 days-9 to -8 °F: 0 days-8 to -7 °F: 2 days-7 to -6 °F: 1 day-6 to -5 °F: 3 days-5 to -4 °F: 6 days-4 to -3 °F: 2 days-3 to -2 °F: 5 days-2 to -1 °F: 3 days-1 to 0 °F: 1 day0 to 1 °F: 2 days1 to 2 °F: 3 days2 to 3 °F: 1 day3 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| 2.85 · P90 |e| 5.93 °F-100+10 °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
-10.00-9.000
-9.00-8.000
-8.00-7.002
-7.00-6.001
-6.00-5.003
-5.00-4.006
-4.00-3.002
-3.00-2.005
-2.00-1.003
-1.00+0.001
+0.00+1.002
+1.00+2.003
+2.00+3.001
+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
2026-08293.25 -2.77

Availability

ModelScored period DaysCoverage
ECMWF AIFS Single2026-08-01 → 2026-08-30 29
ECMWF AIFS Single2026-08-01 → 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) 2 -1.23 [-1.69, -0.77] yes
Aurora (IFS init) 2 -0.13 [-0.36, 0.09] no
FourCastNet v2 (GFS init) 2 -2.06 [-4.97, 0.84] no
FourCastNet v2 (IFS init) 2 -1.60 [-3.96, 0.76] no
NCEP GFS 29 +1.03 [0.43, 1.74] yes
GraphCast (GFS init) 2 -1.67 [-2.73, -0.62] yes
GraphCast (IFS init) 27 +0.40 [0.16, 0.60] yes
ECMWF IFS HRES 23 +0.96 [0.61, 1.66] yes
Pangu-Weather (GFS init) 2 +0.06 [-0.11, 0.23] no
Pangu-Weather (IFS init) 2 +0.16 [-0.68, 0.99] no

Cite this page

ShortCastCheck, KBOS aifs_single lead 0, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KBOS/model/aifs_single/lead/0/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KBOS (Boston Logan), model aifs_single, lead day 0. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KBOS/model/aifs_single/lead/0/

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