A retrospective on the 2025 Atlantic hurricane season

TL;DR

This paper reviews the 2025 Atlantic hurricane season, analyzing environmental factors and their influence on cyclone activity, which was near-average despite warm seas and La Nina.

Contribution

It provides a detailed climatological analysis of the 2025 season, comparing environmental drivers with historical patterns using reanalysis data.

Findings

Early season conditions suppressed cyclone development

Late season activity increased with Kelvin waves and MJO

Overall activity was near-average despite warm sea temperatures

Abstract

Tropical cyclone activity was intermittent during the 2025 Atlantic season, with extended quiet periods. Cumulative activity was near-average relative to 1991-present, despite warm sea-surface temperatures and La Nina conditions. We compare drivers of activity in 2025 with climatology, using reanalysis data to examine variability in environmental conditions, wave activity, and circulation patterns. During the early and peak season, high pressure, a strong upper-level trough and cool equatorial sea-surface temperatures led to weak seed disturbances and unfavourable development conditions. Stronger disturbances coinciding with Kelvin wave activity and favourable MJO conditions led to a more active late season.