Songfacts®:

• This was written in 1934 by Maria Grever, who was the first successful female Mexican songwriter. She wrote it as "Cuando Vuelva A Tu Lado," which translates to "When It returns To Your Side," but for English consumption the lyricist Stanley Adams rewrote it as "What a Diff'rence a Day Made." The Dorsey Brothers Orchestra recorded it with the English lyrics in 1934, and their version was a #5 hit. Many artists have recorded it since, but Washington's version has become the most popular. It was her first hit and also the first hit for the songwriter Grever.
• Other artists to record this include Chet Baker, Ray Conniff, Sarah Vaughan, Bobby Darin, and Deborah Cox. In 1975, a dance version by Esther Phillips hit #20 in the US. Weird fact: Phillips was born Esther Mae Jones, Dinah Washington was born Ruth Lee Jones.
• Washington won a Grammy for Best Rhythm & Blues Performance for her version.