The normal onset date for the monsoon in Kerala is June 1, but the intensifying low-pressure systems, high humidity, and active cloud patterns over the Arabian Sea are aiding its accelerated movement this year.

Historical Monsoon Onset Trends in Kerala

Earliest ever recorded: 11 May 1918

Latest onset: 18 June 1972

Most recent early arrival: 23 May in 2001 and 2009

Delayed monsoon in recent memory: 9 June 2016

Why Monsoon Onset Is Crucial for India

India receives about 70% of its annual rainfall during the monsoon months (June to September). The arrival of the monsoon:

Replenishes groundwater and reservoirs

Is vital for kharif crop sowing

Boosts rural income and food security

Impacts GDP through agriculture’s contribution

IMD has predicted above-average rainfall for 2025, increasing expectations of record kharif output, especially in rice, maize, cotton, soybean, and oilseeds.

Weather Systems Supporting Early Monsoon

A low-pressure area is active over the east-central Arabian Sea , which is expected to intensify and move northward in the next 36 hours.

This system is enhancing moisture inflow across Kerala and neighboring states.

Kerala has already experienced widespread rainfall over the past two days due to advancing monsoon conditions.

Where Is the Monsoon Headed Next?

According to IMD, the southwest monsoon is likely to advance into:

South and Central Arabian Sea

Maldives and Comorin region

Lakshadweep Islands

Parts of Karnataka, Tamil Nadu

South and central Bay of Bengal

Northern Bay of Bengal and northeast India

This marks a rapid progress, suggesting timely rain for most parts of India.

Impact on Agriculture and Economy

The early monsoon could:

Help pre-monsoon sowing activities

Improve reservoir levels ahead of the rabi season

Boost rural confidence

Contribute to GDP growth through increased farm output

Farmers across states like Maharashtra, Gujarat, Madhya Pradesh, and Chhattisgarh will benefit from early field preparation and timely sowing.

Relief from Heatwave Expected

Large parts of India, especially central and northwestern regions, have been reeling under heat. The advancing monsoon is expected to ease temperatures and reduce heatwave conditions, especially along the western coast and interior southern India.

Close Monitoring by IMD

IMD officials are monitoring monsoon conditions in real time, with a ±4-day model margin for Kerala’s onset. This year’s forecast falls well within that window, suggesting a high degree of accuracy.

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Notably, in the last 16 years, this year’s monsoon onset is set to be the earliest. Moreover, the state has developed all the favourable conditions for the onset of the monsoon, as it received heavy rainfall in various parts of it over the last two days.

The weather office’s Trivandrum unit shared a post on X (formerly called Twitter) on Friday, “Monsoon onset likely over Kerala in the next 2 days. Strong westerlies may bring very heavy to extremely heavy rain. Stay alert and follow advice from the authorities. Check the district-wise warnings.”

🌧️ Monsoon onset likely over #Kerala in next 2 days. 🌬️ Strong westerlies may bring very heavy to extremely heavy rain. ⚠️ Stay alert and follow advice from the authorities. 📍Check the district wise warnings. #Monsoon2025 #KeralaWeather #HeavyRain pic.twitter.com/OfGT5mPdD2 — Meteorological Centre, Kerala weather, Trivandrum (@imd_trivandrum) May 23, 2025

Kerala to witness the earliest monsoon in the last 16 years

The recent rainfall is believed to be the combination of a low-pressure area and the advancing monsoon system. This is the earliest monsoon Kerala is going to witness after the last 16 years. The last time this happened was in 2009 and 2001, when the monsoon reached the state on May 23.

On May 24, 2025, a Depression has made landfall between Ratnagiri and Dapoli, anchoring itself over Maharashtra. The southwest monsoon has unleashed its magic in the last 24 hours, blessing regions like Nilgiris’ Avalanche and Upper Bhavani with significant rainfall. This is just… pic.twitter.com/eAtt6JSYvb — Emmanuel Paul (Dendrophile) (@PYWeatherman) May 24, 2025

According to a senior IMD official, who told Live Mint that the conditions are favourable and the monsoon is advancing as per the schedule. “If conditions remain conducive, then it is likely to hit the Kerala coast by 25 May, as predicted by us,” he quoted Live Mint.

The IMD also issued a red alert for the Thiruvananthapuram district on Friday evening after heavy rains disrupted normal life. The alert was issued for three hours of heavy rainfall along with surface winds reaching 50 kmph, as per PTI.

Credit: X | IMD

A look at the state-wise rainfall forecast here

Heavy rainfall is likely over Kerala and coastal Karnataka through May 29, including the states of Tamil Nadu, Telangana, and Andhra Pradesh.

Maharashtra: According to the weather report, a depression has formed over the east-central Arabian Sea near the south Konkan coast; hence, it is expected to shift eastwards and cross the coast between Ratnagiri and Dapoli this morning.

Meanwhile, the IMD on Friday issued a red alert predicting heavy rainfall in the coastal districts of Maharashtra.

Depression over Eastcentral Arabian Sea and adjoining south Konkan coast

The Depression over Eastcentral Arabian Sea and adjoining south Konkan coast moved slowly eastward with a speed of 6 kmph during past 3 hours and lay centred at 0830 Hrs IST of today, the 24th May 2025 over… pic.twitter.com/ZUFnO5AJWh — India Meteorological Department (@Indiametdept) May 24, 2025

Delhi-NCR: Light rain is expected in parts of South Delhi and the National Capital Region (NCR) over the next two hours, as per IMD. On Friday, an orange alert was also issued for Delhi-NCR.

Northern states: Among the northern states, such as Uttarakhand, Himachal Pradesh, and Uttar Pradesh, the IMD has forecasted fairly widespread rainfall with thunderstorms, lightning, and gusty winds of 40-50 kmph on May 24.

While parts of Jammu & Kashmir, Ladakh, Punjab, Haryana, Chandigarh, and Rajasthan are also likely to receive light to moderate rain.

With favorable atmospheric conditions in place, the monsoon, which had stalled about 40–50 km off the coast for four days, advanced rapidly on Friday evening. The system is now expected to cover parts of Tamil Nadu and Karnataka by today, and is likely to spread to southern and northeastern India within a week. Central and eastern India could see monsoon rains by June 4, significantly ahead of schedule.

No El Niño Threat, Strong Rainfall Expected

IMD scientists have stated that El Niño conditions are absent this year, raising hopes for normal to above-normal rainfall during the 2025 monsoon season. In contrast, last year’s active El Niño resulted in 6% below-normal rains across the country. The lack of El Niño, and possible emergence of La Niña conditions, are expected to enhance rainfall across India.

El Niño vs La Niña: El Niño leads to warmer sea surface temperatures, often disrupting normal rainfall patterns.

La Niña, marked by cooler ocean temperatures, typically brings cloud formation and heavier rainfall, especially over South Asia.

Heavy Rainfall and Heatwave Alerts Across India

While the southern states prepare for a rainy week, IMD has issued dual red alerts for May 24 — one for heavy rainfall in Kerala, Karnataka, Goa, Maharashtra, and Gujarat, and another for extreme heat in parts of Rajasthan and adjoining northwestern states.

Coastal regions could receive up to 200 mm of rain in the coming days.

Western Rajasthan, including Jaisalmer, is under a heatwave red alert until May 27, with maximum temperatures exceeding 48°C.

Sea Access Restricted Until May 27

In light of severe weather and rough sea conditions, fishing and marine activities have been restricted until May 27 along the coasts of Kerala, Karnataka, and Lakshadweep. The IMD has warned of thunderstorms and gusty winds in both coastal and inland areas, urging fishermen and residents to remain cautious.

Fast-Tracking the Monsoon Path

Typically, the monsoon:

Enters Kerala by June 1

Covers the entire country by July 8

Starts withdrawing around September 17

Fully exits by October 15

However, this year’s rapid onset has raised expectations of early coverage across India. In 2024, monsoon entered Udaipur region of Rajasthan on its scheduled date of June 25. This year, experts predict monsoon may reach Rajasthan by June 20, continuing the trend of early arrivals.

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Typically, the monsoon hits Kerala by 1 June and then gradually covers the rest of the country by early July.

The monsoon has already covered the entire Lakshadweep region, Kerala, Mahe, parts of Karnataka, the rest of the Maldives, and Comorin area, large parts of Tamil Nadu, and some areas of Mizoram.

It further said that conditions are favourable for the southwest monsoon to advance over the next 2–3 days. It is likely to cover more parts of the central Arabian Sea, the whole of Goa, parts of Maharashtra and Andhra Pradesh, additional areas in Karnataka, the remaining parts of Tamil Nadu, more parts of the west-central and north Bay of Bengal, more areas in the Northeast, and some parts of sub-Himalayan West Bengal and Sikkim.

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Poll Do you think the early arrival of the monsoon will positively impact agriculture this year? Yes No

According to IMD data, the monsoon arrived in Kerala on 30 May last year, 8 June in 2023, and 29 May in 2022. Looking back at past data, the earliest onset ever recorded was on 19 May 1990, which was 13 days ahead of schedule. While the timing may vary each year, meteorologists stress that the date of onset in Kerala does not directly impact the total rainfall or its spread across the rest of India.

IMD had earlier forecast above-normal cumulative rainfall for the 2025 season.

It also ruled out the presence of El Nino conditions — a climate pattern typically linked with below-normal monsoons in India.

According to the IMD, rainfall between 96 per cent and 104 per cent of the 50-year average of 87 cm is considered ‘normal’. Rainfall less than 90 per cent of the long-period average is considered ‘deficient’; between 90 per cent and 95 per cent is ‘below normal’; between 105 per cent and 110 per cent is ‘above normal’; and more than 110 per cent is considered ‘excess’ precipitation.

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India saw 934.8 mm of rainfall in 2024, 108 per cent of the average and the highest since 2020. In 2023, it recorded 820 mm, 94.4 per cent of the average. In 2022, it saw 925 mm; 870 mm in 2021; and 958 mm in 2020, according to IMD data.

The monsoon is crucial for India’s agriculture sector, which supports the livelihood of about 42 per cent of the population and contributes 18.2 per cent to the country’s GDP. It is also essential for replenishing the reservoirs critical for drinking water and power generation across the country.

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The IMD has noted heavy rainfall across several parts of Kerala as a result of a low-pressure area combined with the advancing monsoon system. This early onset is significant given the varied dates of arrival in past years, with the earliest recorded on May 11, 1918, and the latest on June 18, 1972. Over the past 25 years, the most delayed onset occurred in 2016 when it began on June 9.

The IMD has issued a red alert for several districts in Kerala, forecasting significant rainfall exceeding 204.4 mm within 24 hours. Districts such as Kannur and Kasaragod are under alert on May 24, with Malappuram, Kozhikode, Wayanad, Kannur, and Kasaragod following on May 25. An orange alert has been issued for Thrissur, Malappuram, Kozhikode, Wayanad, Kannur, and Kasaragod on May 23, indicating the potential for heavy rainfall and thunderstorms.

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In addition to Kerala, Tamil Nadu, Telangana, and Andhra Pradesh are also expected to experience scattered showers and thunderstorms over the next five days, as indicated by the weather department. The monsoon is projected to move eastwards, crossing the south Konkan coast between Ratnagiri and Dapoli as a depression, further intensifying rainfall in the region.

The IMD follows specific criteria to declare the monsoon’s onset, involving rainfall measurements at 14 key stations, wind patterns, and cloudiness. If more than 60% of these stations report rainfall of 2.5 mm or more for two consecutive days, with favourable wind patterns and low Outgoing Longwave Radiation, the onset is declared on the second day. This year’s early arrival aligns with these criteria, reflecting the dynamic nature of India’s monsoon system.

The India Meteorological Department (IMD) confirmed the onset of monsoon on Saturday, noting that the seasonal rains have arrived earlier than the normal onset date of June 1.

Interestingly, this is the first time since 2009 that the monsoon has arrived as early as May 24.

Last week, the IMD had forecast the likely onset date to be May 27, with a margin of error of plus or minus four days — a prediction that has turned out to be spot-on.

The onset of the monsoon over Kerala signals the beginning of its northward advance, gradually covering the rest of the country through June and typically reaching the farthest corners by mid-July.

On Wednesday, the IMD had hinted at an imminent onset, stating that the established meteorological criteria for declaring the monsoon’s arrival had been met.

At least 60 per cent of the 14 designated weather stations across Kerala and adjoining areas must record rainfall of 2.5 mm or more for two consecutive days for the declaration of monsoon.

The depth of the westerly winds must extend up to 600 hPa. Zonal wind speed at the 925 hPa level should range between 15-20 knots over a specified region. The Outgoing Longwave Radiation (OLR) in a defined area should be below 200 W/m².

After these benchmarks were fulfilled, the monsoon was declared.

Meanwhile, widespread rains have lashed various parts of the state since Friday, leading to waterlogging, road blockages, and uprooting of trees in several districts. The persistent downpour has disrupted vehicular movement in many areas.

State Revenue Minister K. Rajan, addressing the situation on Saturday, said that authorities are on high alert and closely monitoring the developments.

“We urge the public to exercise caution, especially while planning long-distance travel. It is advisable to check weather and traffic updates before heading out,” he said.

–IANS

sg/skp

This early onset marks the earliest arrival of the monsoon in the southern state since 2009, when it reached Kerala on May 23.

According to historical data maintained by the IMD since 1975, the earliest monsoon onset over Kerala was recorded on May 19, 1990—13 days before the usual onset date of June 1.

The onset of the monsoon over Kerala marks the beginning of the four-month-long southwest monsoon season, which brings more than 70% of India’s annual rainfall and is crucial for the country’s agriculture-dependent economy.

“As the monsoon winds strengthen, the rains will advance across the rest of the country through June, typically covering the entire nation by mid-July,” an IMD official stated.

Earlier, the IMD had forecast the onset around May 27, with a margin of plus or minus 4 days. This year’s arrival has thus fallen well within the predicted window, albeit at the earliest edge.

Monsoon Onset Dates Over Kerala (2000–2024):

Favorable conditions for the monsoon’s onset have developed across the state, and a combination of a low-pressure area and an active monsoon system over the past two days has already brought heavy rainfall to several parts of Kerala.

Historically, early monsoon arrivals in Kerala were recorded in 2001 and 2009, with the rains commencing on May 23 during both years.

Typically, the southwest monsoon makes landfall in Kerala around June 1. However, in an exceptionally early instance back in 1918, the monsoon arrived as early as May 11. On the other hand, the most delayed onset was in 1972, when the rains began only by June 18.

Over the last 25 years, the latest arrival of the monsoon occurred in 2016, with the onset recorded on June 9.

Meanwhile, the IMD has issued a heavy rainfall alert for several southern regions, including Kerala, the coastal and interior parts of Karnataka, as well as Konkan and Goa, predicting intense showers on Saturday, May 24.