Around 60 school pupils are braving the windy and wet weather by sleeping outside on O'Connell street for charity.
The Belvedere College pupils spent last night outside the GPO and are set to do the same again tonight. They're raising money for the Fr Peter McVerry Trust, Home Again and Focus Ireland.
The fifth and sixth class students are not getting good weather for their sleep-out, now in its 30th year, as a yellow weather warning is in place.
The boys are hoping to raise more than €100,000 through the sleep-out and have raised more than €1.5m since the idea started.
Lucan's Tom Keane is one of the pupils taking part in the sleep-out. He said people taking part in it get to meet some interesting characters through the sleep-out.
"You really get to appreciate Christmas when you get home and you're able to get into a bed.
"We have gym mats to sleep on. They're not so bad. They don't let the heat go down to the ground."
Mr Keane is joined by James Griffin from Castleknock, who said the first night wasn't too bad.
"It wasn't too stormy and it wasn't too cold, so I think we were lucky enough," he said.
"You get a warning that it's obviously going to be tough. You're living on the street for about three days."
One of the student organisers Rían Hayes said: "The public make all the difference for us, and ultimately the people who spend every day each year on the streets, not just three."
To donate €2 to the sleep-out, text 'SLEEPOUT' to 57802.