Chennai Monsoon 2026: Rain Outlook, Flood Alerts, Helplines & What to Do
Chennai gets most of its rain between October and December, when the north-east monsoon sets in. Most days that means a heavy shower and a wet commute; a few times a decade it means a flood. This page keeps the live outlook, the official alert channels and the helplines in one place.
Live 7-day rain outlook for Chennai
Daily rain total and the highest chance of rain each day, from the Open-Meteo forecast model for central Chennai (13.08°N, 80.27°E).
Also on Chennai Today: school-holiday alerts, power cuts, gold and petrol pointers, the panchangam and events, in one morning page.
On this page
Official alerts: where to check
Forecast models, including the one above, say how much rain is likely. The official warnings that close schools, offices and roads come from a few government channels. As of October 2026, check these each morning:
- IMD Regional Meteorological Centre, Chennai — the RMC Chennai page carries district forecasts, colour-coded warnings (yellow, orange, red) and three-hourly nowcasts. The 7-day forecast and warnings bulletin is a one-page PDF updated through the day.
- Greater Chennai Corporation (GCC) — runs the drains, pumps, relief centres and the 1913 line. Its website and social accounts post waterlogging and school-closure notices.
- Chennai Metro Water (CMWSSB) — water supply and sewerage. Its site did not answer when we checked, so search for it directly for supply notices and its complaint number.
- Tamil Nadu State Emergency Operations Centre (TNSDMA) — evacuation and cyclone advisories. Also unreachable when we checked; its control-room number is printed in the press with every warning.
- Greater Chennai Traffic Police — @ChennaiTraffic on X posts road and underpass closures as they happen. The most useful feed on a wet day.
- Chennai Airport (MAA) — check your airline first, then the Airports Authority of India page for Chennai. Southern Railway posts cancellations on its site and the 139 line; suburban trains stop first when tracks flood.
- Chennai Metro Rail — chennaimetrorail.org. Elevated or deep underground, it has typically kept running through heavy rain.
Yellow means be aware; orange means be prepared and expect waterlogging; red means stay put.
Helplines (verified)
Each number below was read off an official Government of India or Tamil Nadu page on 17 October 2026. Numbers we could not confirm are left out.
| Need | Number | Who answers |
|---|---|---|
| Waterlogging, fallen tree, blocked drain, relief centre | 1913 | Greater Chennai Corporation complaint line |
| Disaster helpline (district) | 1077 | Chennai District emergency operations centre |
| Police | 100 | Police control room |
| Fire and rescue | 101 | Fire control room |
| Ambulance and accidents | 108 | Free state ambulance service |
| Traffic police | 103 | Chennai Traffic Police |
| Train running status | 139 | Indian Railways enquiry |
| Women’s helpline | 181 | State women’s helpline |
Not listed because their sites did not answer: the state control room (TNSDMA) and Metro Water’s line; newspapers print both with every warning, and hotel desks keep them.
Which areas flood first
Chennai is flat and barely above sea level, and its rivers drain slowly when the sea is high. In every serious flood (2005, 2015, 2021, Cyclone Michaung in 2023) the same neighbourhoods went under first.
- Velachery, Pallikaranai and Perungudi — built around the Pallikaranai marsh, the city’s natural sponge; streets hold water for days.
- OMR stretches — Thoraipakkam, Sholinganallur and the IT corridor behind the marsh.
- Mudichur, Tambaram and the upper Adyar near the airport — where Chembarambakkam reservoir releases go; the runway itself flooded in 2015.
- Ashok Nagar, KK Nagar, West Mambalam and Saidapet — low inner suburbs along the Adyar; chest-deep in 2015.
- Kotturpuram, Nandanam and Manapakkam on the Adyar; Pulianthope, Vyasarpadi and Kolathur in the north.
Relatively drier, draining in hours rather than days: Nungambakkam, Egmore, Anna Nagar, Kilpauk, Mylapore, Alwarpet, eastern Adyar and Besant Nagar — the areas we recommend in where to stay in Chennai.
Underpasses and roads to avoid
Road and rail underpasses (“subways” locally) fill first and are the most dangerous; the Traffic Police barricade them and post the list on X. Never drive or walk into standing water you cannot see the bottom of. Typically closed early in a heavy spell:
- Gengu Reddy (Egmore), Duraisamy (T. Nagar) and Rangarajapuram (Kodambakkam) subways on the suburban rail line.
- Kilpauk Garden Road and the Perambur subways in the north.
- Madhya Kailash and Tidel Park junctions on OMR, the Velachery bypass and the Koyambedu approach, which behave like underpasses.
Usually open: the Kathipara flyover and GST Road to the airport, most of Anna Salai, the Marina and the Metro.
Travel and getting around
- Keep a buffer day at each end of a November or December trip. The airport closed for days in December 2015 and for a day in Cyclone Michaung (December 2023); flexible tickets are worth the premium.
- The Metro usually runs and links the airport, Central, Egmore, T. Nagar and Anna Nagar. Buses keep going on main roads; suburban trains stop first.
- Autos and cabs surge; app fares double and drivers refuse flooded suburbs. Agree a price first and expect to walk the last stretch.
- Carry cash. Card machines and UPI fail with the power; two thousand rupees in small notes covers a difficult day. See getting around Chennai.
- Arriving by air, read the airport arrival guide and use the prepaid taxi counter inside the terminal.
Health and water
General travel information, not medical advice:
- Leptospirosis spreads through rat-fouled floodwater. Do not wade barefoot; wash and dry your legs afterwards and cover cuts. Fever a week or two later needs a doctor.
- Dengue peaks in the weeks after heavy rain. Repellent at dawn and dusk, long sleeves in the evening.
- Water: sealed bottled or filtered only; skip ice and cut fruit in a wet week. Many households boil water through the season.
- Pharmacies are everywhere and the big hospitals run normally in all but the worst floods; see Chennai for medical visitors.
Power cuts and staying connected
The electricity board cuts supply to waterlogged streets for safety, so a flooded neighbourhood is a dark one. Mid-range hotels have generators; many apartments do not. Charge everything when the sky darkens, keep a power bank full and download offline maps. Mobile towers fall silent after a few hours, so agree a fixed-hour WhatsApp check-in with family abroad; silence then reads as a dead battery, not an emergency.
What to pack
Add to the normal Chennai packing list for October to December: a sturdy compact umbrella, sandals you can soak, a light rain jacket, zip bags for phone and passport, a 20,000 mAh power bank, a small torch, rehydration salts, repellent and two weeks of any prescription medicine. Keep a change of clothes in your day bag; wet clothes in air-conditioning is how visitors catch colds.
Tips for NRI and overseas visitors
- Travel insurance that covers weather delay and cancellation, not just medical costs.
- Flexible tickets for the leg out of Chennai, on the earliest flight of the day, the one most likely to leave before conditions worsen.
- Check IMD daily from a week before you fly; a Bay of Bengal cyclone is visible five to seven days out, enough time to shift a trip.
- Family WhatsApp groups are how Chennai runs during a flood: which streets are passable, whose generator is on. Join them before you need them.
- Festival dates: the best-time guide explains why late December onward is the sweet spot; if you are fixed around Deepavali or Karthigai Deepam, stay in a drier neighbourhood and keep the buffer day.
Frequently asked questions
When is the monsoon in Chennai?
The north-east monsoon, roughly mid-October to mid-December, with November usually the wettest month. The June to September south-west monsoon largely misses the city.
Is it safe to visit Chennai during the monsoon?
Yes for most of the season: heavy showers, wet commutes and the odd waterlogged street. The floods of 2015, 2021 and 2023 were rare events that IMD warned about days ahead. Stay in a well-drained neighbourhood and keep a buffer day.
Which number do I call for flooding in Chennai?
1913, the Greater Chennai Corporation complaint line, for waterlogging, fallen trees and relief centres. For emergencies use 100 (police), 101 (fire) or 108 (ambulance); the district disaster helpline is 1077.
Does Chennai Airport close during heavy rain?
Rarely, but it has: for several days in December 2015 and about a day during Cyclone Michaung in December 2023. In a normal monsoon flights are delayed rather than cancelled. Check your airline and book a flexible ticket for November and December.