Some Indian festivals move through the seasons because their calendar ignores the sun

Twelve lunar months do not make a solar year

A lunar month is the interval from one new moon to the next, a little over twenty-nine and a half days. Twelve of them come to roughly three hundred and fifty-four days, which is around eleven days short of the time the earth takes to go round the sun.

Most traditional Indian calendars solve this by inserting an extra month at intervals, keeping the lunar months roughly aligned with the seasons. That is why the majority of Hindu festivals move within a season but never leave it, arriving earlier or later in a given month from one year to the next.

The Islamic calendar does not make that correction. It runs twelve lunar months and accepts the shortfall, so every date in it moves backwards through the solar year by about eleven days annually and completes a full circuit over roughly three decades. That single decision has substantial practical consequences.

What the drift means in practice

Ramadan and the festivals that follow it therefore occur at a different point in the year each year, and within a lifetime a person will observe them in every season. Fasting during long hot summer days is a very different undertaking from fasting during short cool winter ones, and both come round in turn.

For a traveller in India, this means the association between a festival and a season simply does not hold for these observances. There is no month in which Eid always falls, and any account that pins one to a particular time of year is describing a single year rather than a rule.

It also means the dates cannot be predicted with total precision far ahead, since the start of a month traditionally depends on the sighting of the new crescent, which is a local observation subject to weather and to the practice of the community concerned. Calculated calendars exist and are widely used, and they do not always agree with the sighting.

The atmosphere in Indian cities during Ramadan

In cities with substantial Muslim populations, the month changes the rhythm of entire neighbourhoods. Activity shifts to the hours after sunset, streets around the major mosques become busy late into the night, and the areas concerned are livelier at eleven at night than at eleven in the morning.

Visitors are generally welcome in these areas, and the evenings around the old quarters of several Indian cities during this month are among the more atmospheric urban experiences available. The usual courtesies apply: dress modestly, be considerate about eating or drinking in public during daylight in those neighbourhoods, and ask before photographing anyone.

The festival that ends the month is a major public occasion with congregational prayers, large gatherings and heavy demand on transport as people travel to be with family. It is a public holiday, so offices and many businesses are closed, which is worth accounting for if the trip involves anything official.

Christmas is a regional season in parts of India

In Goa, in parts of Kerala and Tamil Nadu, across much of the northeast and in pockets elsewhere, Christmas is a major local occasion with substantial public celebration, decorated churches, midnight services and a genuine holiday atmosphere for a fortnight or more.

This coincides with the peak of the domestic and international tourist season in several of those regions, and the result is the busiest and most expensive fortnight of the year in places like coastal Goa. Accommodation, transport and restaurants are all at their limit around the turn of the year.

In the northeastern states the character is different, with strong church traditions and community celebration rather than a resort atmosphere. Travelling there over the period is rewarding and requires more planning than usual, since many businesses close and services thin out over the holiday.

Planning around a calendar that is really several calendars

India observes festivals from several religious traditions, each with its own reckoning, and the national holiday list reflects that. Some dates are fixed, some move within a season, and some move through the year entirely, which is why no single mental model covers the whole calendar.

The practical approach is to check the specific dates for the specific year before booking anything, using an official holiday list or the relevant community’s calendar rather than assuming last year’s pattern. Restricted and optional holidays vary by state as well, so a day off in one place is a working day in another.

None of this makes travel difficult. It does mean that a week chosen at random has a reasonable chance of containing a major observance somewhere along the route, and knowing which one turns an unexplained closure or a crowded train into something you saw coming.