Each new year brings with it a host of holiday style questions. I’m not talking here about what to add to your wardrobe in the January sales, I’m talking about which holiday terms need initial capital letters and which need an apostrophe or hyphen.

To help you get through the year, I’ve written some style tips.

Holidays are typically written with initial capital letters, so it’s New Year’s Day. The apostrophe goes before the s to show that the day belongs to the new year. Even New Year’s, the shortened form of New Year’s Day, takes initial capital letters.

If you add eve or day to the name of a holiday, give it an initial capital as well (New Year’s Eve, but New Year’s resolution).

Despite what the green underlining in your Word document suggests, there is no need to use initial capitals when talking about the new year in general terms.

Greetings

Holiday greetings, except for proper nouns and words that start a sentence, are not capitalised.

“Wishing you a merry Christmas.”

“Have a happy New Year.”

“Happy holidays everyone!”

Epiphany, and other religious days throughout the year (such as Hanukkah, Diwali, and The Day of Ashura) are given initial capitals.

The International Day of Commemoration in Memory of the Victims of the Holocaust, which is often referred to as International Holocaust Remembrance Day, is an international observance designated by the United Nations General Assembly. This title is frequently shortened even further to Holocaust Remembrance Day. The word International is often dropped from international observances in informal situations. You can find the official title of international observances on the United Nations website.

Martin Luther King Jr. Day, which is often written as Martin Luther King Day, is a public holiday in the United States. Like all public holidays, it is given initial capital letters.

Washington’s Birthday is also a public holiday in the United States. It is called Washington’s Birthday even though there is no consensus as to which US presidents are being honoured. Many jurisdictions within the US have renamed it Presidents’ Day. It is usually written with the apostrophe after the s, although the AP Stylebook recommends dropping the apostrophe.

Religious seasons, such as Lent and Advent in the Christian religion and the holy month of Ramadan in Islam, are written with initial capital letters.

Mothering Sunday, which is observed at the end of Lent in the United Kingdom, is increasingly being referred to as Mother’s Day. Mother’s Day is celebrated on the second Sunday of May in most other countries around the world. Both holidays are given initial capital letters.

Does Mother’s Day need an apostrophe?

Sometimes you will see Mother’s Day written with an apostrophe before the s, sometimes with an apostrophe after the s, and sometimes with no apostrophe.

Mother’s Day, with the apostrophe before the s, is the recommended form, as people are honouring their own mother.

Valentine’s Day, Saint Valentine’s Day, or St Valentine’s Day needs an apostrophe before the s. In the US you will see this holiday written as St. Valentine’s Day, but few editors put a full stop on the shortened form of saint in Australia or the UK. The card you send on Valentine’s Day and the person you send it to, are both called a valentine (all lower case). This holiday originated as a feast day in honour of a recognised Christian saint and in some Christian contexts would be titled the Feast of Saint Valentine.

The Feast of Saint Patrick is another Christian feast day. Since St Patrick’s Day (as it is more commonly called) only refers to the one Patrick, it needs an apostrophe before the s. This day is sometimes informally referred to as St Paddy’s Day, (from the Irish name Pádraig). Patrick can also be shortened to Pat, so St Pat’s Day is an acceptable informal alternative. Patty, however, is short for Patricia, so should be avoided.

Daylight Saving Time or Daylight Savings Time?

Daylight Saving Time (DST) is often incorrectly referred to as Daylight Savings Time. Daylight Saving Time is when time is advanced ahead of the standard time of a country or region (usually by one hour).

Daylight Saving Time is sometimes referred to as summer time. British Summer Time (BST) is the term used in some legislation in the United Kingdom.

Dictionaries and style guides differ in their use of initial capital letters.

Most dictionaries and style guides recommend putting an apostrophe after the s in April Fools’ Day (also referred to as All Fools’ Day). The logic behind this is that the day belongs to all the fools in the world, rather than being in honour of an individual fool.

A few dictionaries have April Fool’s Day as the primary or alternative spelling, so putting the apostrophe before the s is considered acceptable. 

If you are referring to the victim of an April Fools’ Day prank, they are called an April fool (with the f written in lower case). Write “April fool!” if you are using it as an exclamation.

Anzac Day is a public holiday in Australia and New Zealand. Although Anzac is an acronym for Australian and New Zealand Army Corps, it is more commonly written with only an initial capital letter. This usage is protected by Australian government regulations. Some institutions prefer to write the title as ANZAC Day.

International Workers’ Day, which is celebrated on 1 May, has the apostrophe after the s, as the day is in honour of all workers. In some countries and regions this day is given the title May Day. Many countries have a Labour Day, either on this day or at another time of the year. In the US it is spelled Labor Day and is celebrated in September.

In many countries, including the UK, USA, IRL and Canada, Father’s Day is celebrated on the third Sunday in June. Father’s Day is treated like Mother’s Day and has an apostrophe before the s. Father’s Day is celebrated on the first Sunday in September in Australia and New Zealand.

Independence Day (US) is informally known as the Fourth of July. You will also see it written as July Fourth and 4th of July. If you need to refer to the holiday at the start of a sentence, it should be spelled out.

Regularly occurring events, such as Sydney’s City2Surf, Pasadena’s Rose Parade, and Frieze London, are given initial capital letters. The numeral 2 in City2Surf is a good reminder to check the correct form of event titles with the organising body.

Every other year you’ll be confronted with the myriad of style issues that arrive with the Olympic Games. Whether it is the Summer Olympic Games or the Winter Olympic Games, it is given initial capitals. Other forms include the Summer Olympics, the Winter Olympics, the Olympics and the Olympic Games. If you are referring to the games, an initial capital letter is optional. Treat the Olympic Games as a plural noun, so write The Olympics are … rather than The Olympics is …

Oktoberfest, which has spread beyond the borders of Germany, should be written with a k, not a c, in recognition of its Bavarian origins.

Halloween is celebrated in several countries on the last day in October. Hallowe’en is usually provided as an alternative spelling. Halloween is short for All Hallows’ Eve (apostrophe after the s). If you were writing historical fiction you might consider using Hallowe’en or All Hallows’ Eve, otherwise stick to Halloween, which is the modern spelling.

Is trick or treat hyphenated?

This is a tricky one. Whether or not to hyphenate depends on how the term is being used.

When the term is referring to the act of knocking on doors and asking for candy, it is being used in the noun form. In this form it is generally not hyphenated.

When the term is used as a verb (“We’ll trick-or-treat all night long”), or is referring to a person doing the trick-or-treating (the trick-or-treater), most dictionaries suggest using hyphens.

The term should also be hyphenated when used as an adjective (trick-or-treat candies).

When it is used as an exclamation (“Trick or treat!”), you can omit the hyphens.

All Saints’ Day is a celebration of all the saints, so the apostrophe goes after the s. The same logic applies to All Souls’ Day.

Remembrance Day is held on 11 November in many countries. It is sometimes referred to as Armistice Day, which it evolved out of. Poppy Day is also a popular name. In the US this observance is called Veterans Day (no apostrophe). Although some ceremonies are held on 11 November in the UK, the main observance is Remembrance Sunday, which is held on the Sunday closest to 11 November.

Guy Fawkes Night is commonly referred to as Bonfire Night. This celebration, which is mainly restricted to the UK, is held on the evening of November 5. It is a remembrance of the attempt of Guy Fawkes to blow up the UK Houses of Parliament. No apostrophe is required.

Both the US and Canada have a Thanksgiving Day. You can use either Thanksgiving or Thanksgiving Day for this holiday.

Do you write “a Xmas card” or “an Xmas card”?

To answer this question, you need to think about how you pronounce Xmas. If you pronounce it as krismuhs, use a. If you pronounce it as eksmuhs, use an.

The season of Christmas is sometimes referred to as Christmastide. You can also refer to this time of year as Christmastime or Christmas time (Oxford Dictionaries and AP Stylebook both treat it as one word, but some dictionaries suggest using two words.)

Xmas, a shortened form of Christmas, is not hyphenated.