The India Meteorological Department (IMD) declared the onset of the Southwest Monsoon over Kerala on 26 May 2026, nearly a week ahead of the normal arrival date of 1 June, making it one of the earliest onsets recorded in nearly two decades. IMD declares the monsoon onset only after 60 per cent of designated rain stations record 2.5 mm or more rainfall on two consecutive days, along with the appropriate wind and outgoing longwave radiation (OLR) signatures. The Southwest Monsoon had arrived over the South Andaman Sea and Andaman & Nicobar Islands on 16 May 2026, six days earlier than IMD's forecast. Isolated heavy to very heavy rainfall was recorded over Kerala and Tamil Nadu on 26 May. At the same time, the country witnessed contrasting weather as severe heat wave conditions continued over Central and Northwest India. The IMD warned that heat wave to severe heat wave conditions were likely over Central and Northwest India during the next 3-4 days, with severe heat wave conditions expected in some pockets over Punjab, Haryana, Chandigarh, Delhi and Uttar Pradesh on 26 and 27 May. Maximum temperatures over Delhi were forecast to range between 43 and 45 degrees Celsius. The National Disaster Management Authority and IMD have operationalised Heat Action Plans across 23 states under the National Framework for Heat Wave Management. The Southwest Monsoon brings about 75 per cent of India's annual rainfall and is crucial for agriculture, drinking water supply, hydropower and overall economic activity.
India Meteorological Department Declares Southwest Monsoon Onset Over Kerala on 26 May 2026 Nearly a Week Ahead of the Normal 1 June Arrival Date Making it One of the Earliest Onsets in Two Decades With Isolated Heavy to Very Heavy Rainfall Over Kerala and Tamil Nadu Even as Severe Heat Wave Conditions Persist Over Northwest India and Maximum Temperatures in Delhi Forecast to Range Between 43 and 45 Degrees Celsius on 26 and 27 May Under IMD Heat Action Plan
IMD declared Southwest Monsoon onset over Kerala on 26 May 2026, nearly a week ahead of the normal 1 June date - one of the earliest onsets in two decades. Northwest India simultaneously faced severe heat wave with Delhi temperatures forecast at 43-45 degrees Celsius.
Key facts
- Southwest Monsoon declared over Kerala on 26 May 2026 - nearly a week before normal 1 June date
- One of the earliest monsoon onsets recorded in nearly two decades
- Monsoon reached Andaman and Nicobar on 16 May 2026 - six days ahead of forecast
- Heavy to very heavy rainfall over Kerala and Tamil Nadu on the onset day
- Severe heat wave continues over Northwest India with Delhi at 43-45 degrees Celsius on 26-27 May
- Heat Action Plans operationalised in 23 states under National Framework for Heat Wave Management
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Practice MCQ from this story
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Consider the following statements regarding the Southwest Monsoon onset over Kerala in May 2026: 1. The normal date for Southwest Monsoon onset over Kerala is 15 May. 2. The IMD declared the onset over Kerala on 26 May 2026, nearly a week ahead of the normal date. Which of the statements given above is/are correct?
Only statement 2 is correct. The normal date for Southwest Monsoon onset over Kerala is 1 June (not 15 May). The IMD declared the 2026 onset over Kerala on 26 May 2026, nearly a week ahead of the normal 1 June date, making it one of the earliest onsets recorded in nearly two decades.
Source: India Meteorological Department
Frequently asked questions
When did the IMD declare the Southwest Monsoon onset over Kerala in 2026?
The IMD declared the Southwest Monsoon onset over Kerala on 26 May 2026, nearly a week ahead of the normal arrival date of 1 June, making it one of the earliest monsoon onsets recorded in nearly two decades.
What are the IMD criteria for declaring monsoon onset over Kerala?
IMD declares onset only after 60 per cent of designated rain stations record 2.5 mm or more rainfall on two consecutive days, along with appropriate wind speed/direction and outgoing longwave radiation (OLR) signatures consistent with monsoon dynamics.
What was the heat wave situation in India on 26 May 2026?
Severe heat wave conditions continued over Central and Northwest India with maximum temperatures in Delhi forecast between 43-45 degrees Celsius on 26-27 May; severe heat wave was expected in pockets over Punjab, Haryana, Chandigarh, Delhi and Uttar Pradesh.
What percentage of India's annual rainfall does the Southwest Monsoon bring?
The Southwest Monsoon brings about 75 per cent of India's annual rainfall and is crucial for agriculture, drinking water supply, hydropower generation and overall economic activity.
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