Whatever you do on Saturday, we want you to capture it on camera and share it with other readers as a unique snapshot of life in our communities.
This year we've got a great prize up for grabs – a seven-night family stay at a wide choice of Innkeeper's Lodge hotels, worth up to £595. There's also a runners-up prize of a three-night family stay, worth up to £255. (See details on www.innkeeperslodge.com).
Last year Jamie Pook of Baffins Road, Portsmouth, came second and won a £200 digital camera.
His picture of wife Kerri and son Lennie, aged 22 months at the time, on holiday in Ibiza, perfectly captured their family summer.
Jamie, 27, said: 'It was my wife who sent the picture in to the competition, she likes things like that. I didn't think I was going to win, as it's usually her that takes the pictures.
'The first we heard I had come second was in the paper and then we had a few phone calls. I was very surprised.'
He added: 'I would say to other people give it a go, there's no harm in trying. I think I might enter again this year.
'My wife is about to have another baby – she is due any time now. So the next pictures I'll take with the camera I won will be of my new baby boy.'
So don't forget, get out there on Saturday and get snapping. We'll publish all your photos on www.portsmouth.co.uk, our website, plus selected ones in The News. We'll also be producing a special supplement later this year.
To see a gallery of last year's great pictures,
go to www.portsmouth.co.uk/onesummersday2007

Click here for details of how to enter.