The phrase "a fateful day" is correct and usable in written English.
It can be used to describe a day that has significant or decisive consequences, often with a sense of inevitability.
Example: "On that fateful day, everything changed for the small town, as the storm swept through and left destruction in its wake."
Alternatives: "a pivotal day" or "an important day".
April 15 1984 was a fateful day: Louise's 16th birthday.
I was only 15 when I first read it – a fateful day".
But on a fateful day last May she slid off a leg-strengthening machine head first, and her neck landed hard on a metal part of the equipment.
On a fateful day in Lima, Peru, in the spring of 1966, Ms. Kanakaris was abandoned by her husband, who also left behind their seven children.
But what is certain is that on a fateful day in 2004, Rob Thomas made a decision that changed his life.
After a fateful day of re-tweeting Russell Brand, they take to the streets in a futile gesture of common understanding.
On a fateful Tuesday less than three years before that, Mr. Harrington drove his train backward to keep passengers away from ground zero, an act that earned him an award from the authority.
It was a fateful Saturday morning, when I came in for my call, I found both Tammy and her mother sporting an evil grin.
This time I had no witty jokes or soothing words which could calm her down, and I had not seen her that distressed since a fateful Tuesday in September.
As dawn breaks on a fateful Sunday in December 1941, Captain Torrey -- with his broken marriage to a Wall Street heiress and estranged son in the rear view mirror and all his belongings in his old sea chest -- is commanding a old cruiser off the coast of Oahu, his charismatic alcoholic best friend (Kirk Douglas) serving as his very capable but volatile executive officer.
For Jake Doyle, this device of superlative fun is nothing but a rumor until, one fateful day, a classmate named Timmy Kleen becomes the first kid on his block to acquire the mythical NES.
