The Grand Retreat of the Southwest Monsoon
The single biggest driver of October's weather is the withdrawal of the mighty southwest monsoon. After dominating India's climate from June to September, this seasonal powerhouse begins its retreat. By the beginning of October, it has typically withdrawn
from the northern plains. This process starts in west Rajasthan around mid-September and gradually moves southeast. The withdrawal is triggered by the weakening of the low-pressure system over the northern plains, which is replaced by a high-pressure system, causing the moisture-laden winds to recede. The 2026 southwest monsoon season officially ended on September 30th, with a rainfall deficit of about 12.6%, making it the driest since 2015. This retreat paves the way for clear skies and a significant drop in humidity, especially across northern and central India.
Arrival of the Northeast Monsoon
While the southwest monsoon says goodbye, another, lesser-known monsoon prepares to make its entrance. The period from October to December marks the northeast monsoon season. Unlike its predecessor, which covers the entire country, this system primarily affects India's southeastern peninsula. It brings crucial rainfall to states like Tamil Nadu, Rayalaseema, coastal Andhra Pradesh, and parts of Kerala. The winds reverse direction, blowing from the northeast and picking up moisture over the Bay of Bengal. Conditions are expected to become favourable for the onset of the 2026 northeast monsoon between October 15 and 21. For these regions, October isn't the end of the rains but the beginning of their main rainy season.
The Notorious 'October Heat'
In many parts of India, particularly in the western and northern regions, the monsoon's retreat doesn't immediately usher in cool winter weather. Instead, it can lead to a phenomenon known as 'October heat'. As the cloud cover from the monsoon disappears, the sun's rays beat down intensely on the still-moist land. This combination of rising temperatures and high residual humidity creates an oppressive, sultry climate that can feel more uncomfortable than the dry heat of summer. This period of hot and humid daytime weather is often punctuated by cool and pleasant nights, marking a true transitional phase before the rapid cooling that begins in the latter half of the month in northern India.
Pleasant Days and Clear Skies Up North
For North India, October is arguably one of the most pleasant months of the year. With the monsoon gone, the region experiences clear blue skies, balmy sunshine, and a welcome drop in both temperature and humidity. Daytime temperatures become comfortably warm, often hovering around 30-34°C in places like Delhi and Rajasthan, while nights become cool. This delightful weather makes it the perfect time for outdoor activities and marks the beginning of the peak tourist season for popular destinations like the Golden Triangle (Delhi, Agra, Jaipur) and Varanasi. The festive season, including Dussehra and the lead-up to Diwali, often coincides with this beautiful weather, adding to the cheerful atmosphere.
A Watchful Eye on Cyclone Season
October is not just a month of transition; it's also a time for vigilance, particularly along India's coastlines. The post-monsoon period, from October to December, is a primary season for the formation of tropical cyclones in both the Bay of Bengal and the Arabian Sea. The warm sea surface temperatures left behind by the summer and monsoon seasons provide the energy needed for these powerful storms to develop. Historically, many devastating cyclones have formed during this window, posing a significant threat to coastal districts in states like Odisha, Andhra Pradesh, West Bengal, and Tamil Nadu. While the withdrawal of the main monsoon brings relief from daily rains, it also opens the door to these more intense and potentially destructive weather systems.
