'I was out today' is correct and usable in written English. You can use it when you want to inform someone about your whereabouts on the current day. For example, you could say, "I was out today, so I wasn't able to finish the report.".
Yesterday I was out, today I'm in.
But then – like Michael Corleone trying to go straight – just when I thought I was out, Christmas pulls me back in.
"I know that the government will not respond to our demands, but I am out today to tell the world what is happening to us," said Asad Mahmood, 50, a demonstrator.
"I'm out today because this is a time of crisis for Israel," another man said.
"My wife and I were out late last night, and we were woken by the fire trucks and phone calls saying, 'Get out, the apartment building is on fire,"' Mr. Basile said.
The nu-disco tune "I Like It" is out today and can be heard above.
However, I was out last week and drove past a roundabout stuffed full of those preposterously colourful primroses you get in the winter.
Awesome tool! I started using it one year ago and I never had to look for another app
Ha Thuy Vy
MA of Applied Linguistic, Maquarie University, Australia