Nearly every store has holiday customers who only buy in December.
You probably won't be able to convince them to buy more frequently but you can get them to buy every year.
What you'll want is a kind of anniversary campaign. This will email them once or twice every December as a reminder to buy. It can include your best selling products, deals, or any other incentive that has worked well this year.
Segment your customers to the ones who first bought in a December, haven't bought any other times, and haven't bought this December.
(You can do the same for November too)
Though it won't pick up a lot of orders, this could get you enough to make it worthwhile. It's especially valuable now when customer acquisition costs are so high.
You can use the Cohort reports in Repeat Customer Insights to find these customers. Look for customers in last December's cohort with only one order.
Eric Davis
Customer behavior analysis for better Shopify store performance
The Shopify App that increases repeat customer purchases through customer behavior analysis.