Tau Day 2017: When Is Tau Day? πŸ—“

When is Tau Day 2017? This year Tau Day is celebrated on a Wednesday, June 28, 2017. In 2018, Tau Day is on Thursday, June 28, 2018.

Tau Day, an anti-Pi Day holiday, is an unofficial observance held every year since 2010 on June 28, or 06/28 as written in the American date format.

The day began as a way to recognize tau, ?, a ratio constant describing the relationship between the circumference and the radius of a circle. In recent years, some mathematicians and physicists have argued for the replacement of pi (?) by tau.

Countdown to Tau Day date is below, plus holiday history, celebration info, facts and holiday details.

When is Tau Day 2017? This year Tau Day is on Wednesday, June 28, 2017.


The concept of replacing pi by tau as a better way to describe the relationship between a circle’s circumference and its radius was first brought up by mathematics professor, Bob Palais in the Mathematical Intelligencer in an article called ? is wrong! . This was followed by the publishing of the Tau Manifesto by physicist Michael Hartl. Both of these articles called for the replacement of pi by tau. Tau, the ratio of a circle’s circumference to its radius, is equal to 2 ? or 6.283.

Below you will find all the details for Tau Day 2017 including, are banks open, is there mail delivery and related holiday information.

Is Tau Day a federal holiday?

No, Tau Day is not a federal holiday. There are ten annual US federal holidays on the calendar designated by the United States Congress. The following federal holidays are established by law:

  • New Year’s Day
  • Birthday of Martin Luther King, Jr. (Third Monday in January).
  • Washington’s Birthday (Third Monday in February)
  • Memorial Day (Last Monday in May)
  • Independence Day (July 4)
  • Labor Day (First Monday in September)
  • Columbus Day (Second Monday in October)
  • Veterans Day (November 11)
  • Thanksgiving Day (Fourth Thursday in November)
  • Christmas Day (December 25)

Is Tau Day a national holiday?

Tau Day is not a national holiday. Unlike many other countries, there are no ‘national holidays’ in the United States because Congress only has constitutional authority to create holidays for federal institutions. Most federal holidays are also observered as state holidays.

Is Tau Day a paid holiday?

No, Tau Day is not a paid holiday. The Fair Labor Standards Act (FLSA) does not require payment for time not worked, such as vacations or holidays (federal or otherwise).

Does the mail run on Tau Day?

Yes, there will be mail delivery on Tau Day. All post offices and federal offices of any kind will be open for the holiday, which means businesses and homes will receive mail. This also counts USPS and Fedex packages. See holiday schedule on USPS and Fedex. The only time mail is not being delivered is on federal holidays, which are listed above.

Are banks open on Tau Day?

Tau Day is a Fun holiday, which means all federal offices, courts and most banks will be open. While most banks are open, some banks can operate on their own schedules, so it may be best to check with your local branches. U.S. stock and bond markets like the New York Stock Exchange and NASDAQ will be open. Grocery stores and malls are reportedly open.

If your bank is closed, it is still possible to conduct general banking transactions via ATM, online banking or your mobile phone. Apps and websites are running though not all normal functions may be accessed for the holiday.

Are stores open on Tau Day?

On Tau Day, most stores, restaurants, shopping centers, and malls are open. There are no holidays on which all businesses are closed by law. However, some stores may have shortened or extended holiday hours for the day. Stores may be operating on holiday schedule with limited or reduced hours of operation. Some businesses may be closed on in order to give their employees the day off. For restaurants, stores and other establishments specific to your area, you will have to check with the individual business.

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Tau Day 2017

Holiday: Tau Day
Date: June 28, 2017
Weekday: Wednesday
Holiday Type: Fun
Tau Day 2018: Thursday, June 28, 2018
Tau Day 2019: Friday, June 28, 2019
Tau Day 2020: Sunday, June 28, 2020

Fun Holiday Fact

Did you know … that Michael Hartl, called for renaming March 14 (3/14) or Pi Day to Half Tau Day?

How To Celebrate Tau Day

Because the value of tau is twice the value of pi, proponents of tau day call for β€œtwice as much of pie” and to eat circular shaped food. So, instead of one slice of pie, eat two or four.

If you are a teacher, use this day to encourage students to get interested in mathematics and to consider mathematics as a career choice.

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