A satellite-era latitudinal climatology of global tropical cyclone intensity from IBTrACS (1966–2025)

We treat the IBTrACS v04r01 satellite era (1966–2025) as a 6-hourly point cloud and scan along latitude. The working set comprises 406,059 fixes from 6,661 storms across 60 seasons. Our main finding is a systematic poleward displacement of the observed intensity envelope relative to the SST-only benchmark: the DeMaria–Kaplan SST-only intensity peak sits at 10.0 degrees N and 8.0 degrees S, whereas the observed 99th-percentile wind envelope peaks at 17.5 degrees N and 16.9 degrees S—approximately 8 degrees poleward in both hemispheres, consistent with maximum potential intensity theory. Inside the equatorial band (|latitude| ≤ 5 degrees), the hurricane-strength share is 2.64% against 24.00% off-band; the off-band rate exceeds the equatorial-band rate in every 1 of 2,000 bootstrap resamples, with a central difference of +21.4 percentage points (95% CI [+18.1, +24.1]). The 99th-percentile wind envelope forms an inverted U: it peaks at 130 kt near 17.5 degrees N and exceeds 120 kt across a 14-bin contiguous plateau (12.5–26.5 degrees N). The Southern Hemisphere plateaus at 110–115 kt across 11.5–21.5 degrees S and never exceeds 120 kt, a 1.5-degree hemispheric asymmetry. ENSO modulates the all-basin per-storm peak-intensity latitude by 1.2 degrees between El Niño and neutral states (KS p < 1e-11). The contribution is descriptive: a fixed latitudinal reference frame against which migration trends, basin-specific signals, and climate-model projections can be calibrated. Storm-normalized robustness checks replicate every headline feature. All data are obtained from public archives, and all analyses are fully reproducible.