Quick summary
The DGCA fog window at Delhi runs 10 December to 10 February, and for the coming season it opens on 10 December 2026. An international-to-domestic connection at Terminal 3 needs about two to three hours on a single ticket with through-checked bags, or four to six hours on separate tickets. Fog is thickest between roughly 3am and 10am.
Low-visibility landings are possible at 800 metres or less, but they do not prevent cancellations: 128 flights came off the board at Delhi in a single day on 29 December 2025. This guide covers buffers, transit and visa rules, and what to do when fog breaks a connection.
The DGCA’s low-visibility window for Delhi opens on 10 December 2026 and runs to 10 February 2027. For anyone connecting through Indira Gandhi International over those two months, the question is how much slack an itinerary needs to survive the fog.
For a long-haul arrival from Europe, North America or Australia, the answer rests on the booking. One ticket and two separate tickets need different buffers. Most of that difference is immigration, baggage collection and re-check. The time of arrival matters as much as the wait.
Why Delhi fog season is a connection risk
India’s Directorate General of Civil Aviation sets the winter low-visibility period at Delhi as 10 December to 10 February. During that period, the airport’s operating rules change. CAT III low-visibility procedures activate when visibility falls to 800 metres or less. At 550 metres, departure and arrival rates start to be restricted.
Fog at Delhi follows a daily rhythm. It is thickest between about 3am and 10am, putting early-morning arrivals and the domestic legs that follow them in the worst hours. Long-haul arrivals are more likely to land than the short domestic flights behind them. The risk sits on the connection rather than the inbound aircraft.
The month matters too: a Weathernews seasonal analysis puts January above 25 fog days, making it the worst month of the window.
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How long a buffer you actually need
The buffer turns on one thing: one booking or two. An international-to-domestic connection at Terminal 3 needs roughly two to three hours when both flights sit on a single ticket with bags checked through to the final city. On two tickets, the same connection needs four to six hours, because you collect your bags, clear immigration and check in again.
Three hours is a workable window for a single-ticket international-to-domestic connection when the onward domestic flight also leaves from T3. Delhi’s international arrivals land there.
An arrival at 14:00 gives the connection the whole afternoon; an arrival at 03:00 puts it inside the day’s worst visibility band.
Immigration, transit, and terminal logistics
A Delhi connection’s visa requirement turns on whether you leave the airside area. Stay inside Terminal 3’s international transit area for under 24 hours, on a single booking with through-checked bags, and no Indian visa is required. Clearing immigration turns the same layover into an entry into India.
A transit visa exists, but it has to be arranged in advance. Most US, UK, EU, Canadian and Australian passport holders use the e-Visa, applied for online before travel. The same rule catches travelers heading beyond India: a Bhutan connection via Delhi needs an Indian visa when the tickets are separate, because the bags have to be collected and re-checked.
Domestic departures can leave from T3 or T1. That terminal split matters in a short connection.
What to do if fog disrupts your connection
A fog cancellation leaves two options: the next available seat on the airline’s network, or a refund of the sector you did not fly. Hotel rooms and meal support are separate. They vary by airline and by the fare you bought. Having both flights on one booking may influence the assistance you are offered.
The shortage is seats, not permission to rebook. On 29 December 2025, when 128 flights were cancelled at Delhi in one day, the constraint was seats that had not already been sold.
Diversions can take passengers well beyond the airport. On 7 May 2026, visibility at Delhi fell below 400 metres and 11 flights were sent to Jaipur.
Roughly 280 kilometres away, 400 to 500 passengers waited four to six hours before continuing. That date falls well outside the DGCA window: the December-to-February calendar is a planning tool, not a guarantee.
Lock the details before 10 December
The useful checks are the ones made while the booking is still changeable.
- Match the terminal: confirm whether the onward domestic leg leaves from T3 or T1, because a T1 departure adds an inter-terminal transfer to whatever buffer you planned.
- Check the bag tag: if it reads only as far as Delhi, the connection will require an entry into India and the paperwork that goes with it.
- Start the e-Visa two weeks out if there is any chance the trip involves leaving Delhi’s airport: processing has run 8 to 10 days or more during 2025–26, and there is no visa-on-arrival or transit visa counter at the airport for most Western passports.
- Watch: the DGCA’s published low-visibility dates and your airline’s schedule revisions in the weeks before 10 December 2026.
The e-Visa covers the case where a rebooking pushes you past the airside definition. The paperwork and bag tag take minutes to arrange now, before the morning the fog settles in.
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Questions? Answers.
What visibility level triggers CAT III operations at Delhi?
Low-visibility procedures at Delhi activate when visibility falls to 800 metres or less. 550 metres is the level at which the airport starts restricting departure and arrival rates. Not every airline and aircraft is certified for the lowest approach minima, which is why some flights land while others hold or divert.
Do airlines guarantee fee waivers during fog delays?
No. A cancellation typically leaves two options: the next available seat on the airline’s network, or a refund of the sector you did not fly. Hotel rooms and meal support vary by airline and by the fare purchased, and having both flights on one booking may influence the assistance you are offered.
Will flights get cancelled due to fog?
Not automatically. Fog alone does not stop operations, because low-visibility procedures allow landings at 800 metres or less. Cancellations come when visibility falls further and the day’s schedule cascades: on 29 December 2025, 128 flights were cancelled at Delhi in a single day.
How much time does it take to clear immigration at Delhi airport?
Budget about an hour for immigration and customs at Terminal 3, plus an hour of check-in buffer before a domestic departure. Foreign arrivals who clear immigration must also file an online e-Arrival card within 72 hours before landing.
