Port Blair Weather Guide: Entering the Monsoon's Final Act

The Rhythm of the Tropical Transition

Visiting Port Blair on September 1st places you at a climatic crossroads. This period marks the final phase of the Southwest Monsoon, a season that has been saturating the Andaman archipelago since May. While you won't encounter the incessant, heavy deluges of July, the atmosphere remains highly active and theatrical. You can expect a landscape that is at its most vibrant—a deep, "electric" green that only months of consistent rainfall can produce.

Daily Atmospheric Patterns

The weather in early September follows a distinct tropical cycle. Days often begin with a deceptively calm, overcast sky or even patches of morning sunshine. However, as the sun heats the moisture-laden ground, vertical clouds quickly build.

• Morning: Generally mild and humid. You may wake up to mist or light fog clinging to the dense inland forests, which burns off by mid-morning.
• Afternoon: This is the most common window for "theater." Sudden, heavy thunderstorms are frequent, often lasting for 30 to 60 minutes before giving way to sudden clarity. These are localized; it may be pouring at the Cellular Jail while the sun shines at Corbyn’s Cove.
• Evening: As the sun sets, a slight cooling occurs, though the humidity remains high. The air often feels "heavy" and still unless a sea breeze picks up from the Bay of Bengal.

Humidity and the "RealFeel"

Numbers can be misleading in this region. While the thermometer might hover around 85°F (29°C), the humidity level is consistently near 80-90%. This creates a "sauna effect" where the air feels significantly warmer than the actual temperature. Expect to feel damp even when it isn't raining; sweat does not evaporate quickly in this saturated environment. The sun intensity during clear breaks is extreme due to the low latitude, making sunscreen essential even on cloudy days.

The Marine Environment

For locals, the sea is the ultimate weather vane. In early September, the Southwest Monsoon winds are still influential, meaning the Andaman Sea can be restless.

• Sea State: Expect choppy waters and moderate swells. Inter-island ferries may experience occasional delays, and the underwater visibility is often lower than in the dry season due to sediment stirred up by rain and wind.
• Trade Winds: You will feel the pulse of the monsoon trade winds—steady, warm breezes that provide some relief from the heat but also bring sudden squalls from the horizon.

A Season of Rejuvenation

September is historically one of the wettest months, yet it is favored by those who seek the islands' raw, natural beauty. Unlike the parched, brown landscapes seen in the peak dry season (February–March), the Port Blair of September is a lush, dripping paradise. Waterfalls in the surrounding hills are at full volume, and the air is remarkably clean, washed of dust by the seasonal rains. Locally, this is a transitional period where the island begins to prepare for the peak tourist influx in October, offering a quieter, more authentic experience amidst the moody tropical skies.