A few years ago you would have been thought of as eccentric if you’d suggest planting potatoes in August. Lots of garden centres are now selling seed potatoes labelled “Christmas” but in fact they are mostly only First Early varieties so don’t go throwing away money on expensive labelling.
Find a First Early seed potato and plant as you usually would. I would suggest planting into pots because later in the year when Late Blight hits main crop potatoes, you can move the pots inside if blight is predicated in your area. Then have the pleasure on Christmas morning of turning out your pots and eating fresh homegrown potatoes around the table.