For Americans and British, today being Friday the 13th is an unlucky day, just as for us is a Tuesday the 13th. Below information taken from the Wikipedia about this tradition of unlucky days:

Friday the 13th is considered an unlucky day in Western superstition. It occurs when the 13th day of the month in the Gregorian calendar falls on a Friday, which happens at least once every year but can occur up to three times in the same year. For example, 2015 had a Friday the 13th in February, March, and November, which will happen again in 2026. Leap years that begin on Sunday such as 2012 and 2040, also have three Friday the 13ths in January, April, and July. 2017 through 2020 had two Friday the 13ths, as did 2023; 2016, 2021, and 2022 had just one Friday the 13th, as will 2025, 2027, and 2028; 2024 will have two Friday the 13ths.

For a month to have a Friday the 13th, the 1st must be a Sunday.

In Hispanic countries, instead of Friday, Tuesday the 13th (martes trece) is considered a day of bad luck.

The Greeks also consider Tuesday (and especially the 13th) an unlucky day. Tuesday is considered dominated by the influence of Ares, the god of war (or Mars, the Roman equivalent). The fall of Constantinople to the Fourth Crusade occurred on Tuesday 13 April 1204, and the Fall of Constantinople to the Ottomans happened on Tuesday 29 May 1453, events that strengthen the superstition about Tuesday.

There is a Tuesday the 13th in months that begin on a Thursday.

On the link below you can find more explanations:

[Taken from USA TODAY]