Tamil Nadu Weather, AQI and Fuel Prices

Why Check Tamil Nadu Weather & Data?

Tamil Nadu is India's second-largest state economy, with a GSDP of roughly ₹31 lakh crore in the 2024-25 advance estimate and the fastest real growth rate, 11.19 percent, among India's large states that year. Chennai's auto belt, stretching through Sriperumbudur, Oragadam and Maraimalai Nagar and nicknamed the Detroit of Asia, builds close to 30 percent of India's total vehicle production and 35 percent of its auto components, while the same corridor now leads the country in electronics exports, $9.56 billion in 2023-24, largely Apple supplier Foxconn and Pegatron's iPhone assembly lines. All of that runs on a monsoon clock unlike anywhere else on India's mainland: Tamil Nadu gets comparatively little from the June-September southwest monsoon that waters most of peninsular India and instead depends on the northeast monsoon, October to December, for close to half its annual rainfall. That inversion means this page's live weather, AQI and fuel numbers serve very different readers on very different calendars, a delta farmer near Thanjavur watching for the northeast monsoon's October onset, a Chennai IT or auto-plant employee checking the evening forecast before a commute that can flood within hours, an airline scheduler bracing for the cyclones that routinely form in the Bay of Bengal each November and December.

Chennai's Deluge, the Coast's Cyclones: Tamil Nadu's Two Real Risks

Tamil Nadu's defining risk isn't summer heat, it is the northeast monsoon and the cyclones that ride in on it. Cyclone Michaung made landfall near Bapatla in neighbouring Andhra Pradesh on December 5, 2023, but Chennai took the worst of it: roughly 60cm of rain fell on the city in 48 hours, Nungambakkam alone recording 47cm, flooding homes, shutting the airport and halting iPhone production at Foxconn and Pegatron's plants nearby. At least 17 to 18 people died in Tamil Nadu in the flooding, according to Reuters and Al Jazeera, with damage estimated near $1.32 billion. Almost exactly a year later, Cyclone Fengal made landfall near Puducherry on November 30, 2024, dumping a 30-year record 48.37cm of rain on Puducherry and roughly 50cm on Tamil Nadu's Villupuram district; at least 13 people died in rain-related incidents across the state, three of them in Chennai, and more than 200 flights were grounded at Chennai airport. Both storms echo the benchmark the state still measures every northeast monsoon against, the 2015 Chennai floods, roughly 290 dead and ₹20,000 crore in losses.

How to Use Tamil Nadu's Data for Daily Decisions

Delta farmers in the Cauvery basin and dryland farmers further south should track the 10-day rainfall outlook from early October, since sowing for the state's key rabi crops depends on the northeast monsoon's onset landing close to its normal October 20 date, a different calendar from the June sowing window most of India follows. Chennai commuters and IT-corridor employees should check the evening rain forecast through October and November specifically, when short, intense bursts have repeatedly flooded low-lying stretches like Velachery and the airport approach road within hours. Auto and electronics manufacturers around Sriperumbudur and Oragadam, and their logistics partners, should build northeast monsoon contingency into November-December production schedules, since Michaung alone halted Foxconn and Pegatron's iPhone lines for days. Anyone travelling through Chennai airport in November or December should check cyclone advisories alongside the daily forecast, not the forecast alone, since both Michaung and Fengal grounded flights with barely a day or two of warning.

Tamil Nadu's Seasonal Calendar

Unlike most of India, Tamil Nadu's main rainy season is the northeast monsoon, arriving around October 20 and running through December, delivering close to 48 percent of the state's annual rainfall in those three months alone. Summer runs March to June, with Chennai regularly crossing 40°C and touching a six-year high of 42.7°C in May 2023, while the state's brief window of southwest monsoon rain, June to September, mainly waters the western districts in the Western Ghats' rain shadow. Deepavali in October or November and Pongal in mid-January both fall close to the northeast monsoon's peak and its tail end, so festival travel routinely overlaps with the season's heaviest rain and highest cyclone risk. Winter, January and February, is short and mild, the calmest stretch for outdoor events and construction. Anyone booking flights through Chennai airport in November or December should build in a buffer day, cyclone-driven grounding has disrupted the airport in back-to-back years.

Tamil Nadu vs Nearby States: Weather & Data Comparison

Figures from IMD climate records, state rainfall data and dated news reports; each state's numbers come from different station sources and years, so treat this as a broad reference, not a single-source dataset.