Modern scholars believe that there is a copying error in the extant manuscripts and that Chaucer actually wrote, "Syn March was gon".

[13] The use of 1 January as New Year's Day became common in France only in the mid-16th century,[8] and that date was not adopted officially until 1564, by the Edict of Roussillon, as called for during the Council of Trent in 1563.

[8] Although no biblical scholar or historian is known to have mentioned a relationship, some have expressed the belief that the origins of April Fools' Day may go back to the Genesis flood narrative.

In a 1908 edition of the Harper's Weekly, cartoonist Bertha R. McDonald wrote: Some authorities gravely go back with it to the time of Noah and the ark.

The London Public Advertiser of March 13, 1769, prints the following paragraph concerning this theory: "The mistake of Noah sending the dove out of the ark before the water had abated, on the first day of April, and to perpetuate the memory of this deliverance it was thought proper, whoever forgot so remarkable a circumstance, to punish them by sending them upon some sleeveless errand similar to that ineffectual message upon which the bird was sent by the patriarch.

This fish feature is prominently present on many late 19th- to early 20th-century French April Fools' Day postcards.

[citation needed] Boulangeries, pâtisseries and chocolatiers in France sell chocolate fishes in their shop windows on the day.

Most news media outlets will publish exactly one false story on 1 April; for newspapers this will typically be a first-page article but not the top headline.

It is a day when many pranks are played: sometimes very sophisticated hoaxes are prepared by people, media (which often cooperate to make the "information" more credible), and even public institutions.

The festival includes a large parade in the city centre, free concerts, street fairs and performances.

One of the traditions on April Fools' Day is to dress up the main city monument in funny clothes.

The BBC was soon flooded with requests to purchase a spaghetti plant, forcing them to declare the film a hoax on the news the next day.

[30] With the advent of the Internet and readily available global news services, April Fools' pranks can catch and embarrass a wider audience than ever before.

In some regions of Hispanic America, after a prank is played, the cry is made, "Inocente palomita que te dejaste engañar" ("You innocent little dove that let yourself be fooled!

In Brazil, the "Dia da mentira" ("Day of the lie") is also celebrated on 1 April[36] due to the Portuguese influence.

In many English-speaking countries, mainly Britain, Ireland, Australia, New Zealand and South Africa, it is a custom to say "pinch and a punch for the first of the month" or an alternative, typically by children.

[43] April Fools' can be good for one's health because it encourages "jokes, hoaxes ... pranks, [and] belly laughs", and brings all the benefits of laughter.

[46] Negative views describe April Fools' hoaxes as "creepy and manipulative", "rude" and "a little bit nasty", as well as based on Schadenfreude and deceit.

[42] When genuine news or a genuinely important order or warning is issued on April Fools' Day, there is risk that it will be misinterpreted as a joke and ignored – for example, when Google, known to play elaborate April Fools' Day hoaxes, announced the launch of Gmail with 1-gigabyte inboxes in 2004, an era when competing webmail services offered 4-megabytes or less, many dismissed it as a joke outright.

Either way, there can be adverse effects, such as confusion,[49] misinformation, waste of resources (especially when the hoax concerns people in danger) and even legal or commercial consequences.

[50][51] In March 2020, during the COVID-19 pandemic, various organizations and people warned not to observe April Fools' Day, as a mark of respect due to the large amount of tragic deaths that COVID-19 had caused up to that point, the wish to provide truthful information to counter any misinformation about the virus, and to pre-empt any attempts to incorporate the virus into potential pranks.

[54] In Thailand, the police warned ahead of April Fools' in 2021 that posting or sharing fake news online could lead to maximum of five years imprisonment.

This turned out to be intentionally misleading, as the episode was instead about Tax Day in the United States, occurring on 15 April.