The best time to buy a Christmas tree is during the holiday season, typically starting from late November and throughout December. Some Christmas tree farms and nurseries may offer pre-ordering options before the holiday season, but most will have their stock available for purchase starting in late November. Be sure to check with your local tree sellers to confirm their specific dates and availability. It's also a good idea to plan ahead and buy your tree early to ensure that you get the size and type that you want, as the best selection can go quickly.