The dry season is tightening its grip over northern Australia, setting the stage for the vast machinery of the Asian monsoon to begin its annual migration northward. The Southern Hemisphere tropics having steadily shut down, the atmospheric focus is shifting decisively toward India and South Asia, where the first signs of the south-west monsoon are already gathering strength over the equatorial Indian Ocean.
Removal of hurdle
The Australian Bureau of Meteorology on Thursday formally declared the 2025–26 northern Australian wet season over, a seasonal turning point watched closely by meteorologists across the Indo-Pacific. The retreat of monsoonal activity from Australia often clears the way for the rapid organisation of weather systems in the Northern Hemisphere, removing one of the last large-scale hurdles to the timely onset of the monsoon over India along Kerala coast around June 1.
Transition visible
The transition is already visible in the movement of the Inter Tropical Convergence Zone (ITCZ), the near-continuous belt of low pressure that circles the globe and steers the world’s monsoon systems in rhythm with the Sun. The ITCZ has now crossed into the Northern Hemisphere, stretching north of Malé in the Maldives and toward the south of Sri Lanka and the Andaman and Nicobar Islands in India. These regions are regarded as the monsoon’s early staging posts before its advance toward the Kerala coast weeks later.
Annual oscillation
From May through September, as northern Australia settles into its long dry season, the Indian monsoon dominates tropical weather narrative. By late September, the cycle reverses once again, with the monsoon trough retreating toward Australia and the Southern Hemisphere tropics. The annual oscillation completes the great seasonal reversal of the monsoon system across both sides of the Equator, as atmospheric heat, moisture and wind regimes migrate between the Northern and Southern Hemispheres in step with the Sun.
Isolated heavy rain
India Meteorological Department (IMD) announced this (Thursday) morning that isolated heavy rainfall is likely over Tamil Nadu, Puducherry and Karaikal and Kerala and Mahe during next seven days and over South Interior Karnataka on today and tomorrow (Thursday and Friday). Pre-monsoon thunderstorms are gathering momentum into early May, with usual onset of the monsoon over Andaman and Nicobar Islands only a fortnight or so away.
Emerging patterns
Isolated to scattered thunderstorms, lightning and gusty winds (30-50 km/hr) are likely over Tamil Nadu, Puducherry and Karaikal; Kerala and Mahe; Rayalaseema; Karnataka, Coastal Andhra Pradesh and Yanam during next five days; Telangana today; Lakshadweep on Saturday ad Sunday.
Weather across North-West and East India may swing between bursts of severe convective activity and intense heat, with thunderstorms, lightning and isolated hailstorms interrupting periods of sharply rising temperatures. The unstable pattern reflects seasonal transition underway, as pre-monsoon heating builds across the plains of North-West even while moisture-bearing winds begin feeding thundercloud development in the interior.
Published on May 7, 2026