There are mattress sales all year round. Some brands pretty much always have the same deal on, others mix things up with different offers on different models at different times, so you need to be more strategic about when you buy.
The lowest prices of the year tend to appear in November in the form of Black Friday mattress deals and Cyber Monday mattress deals, and in February, during the Presidents' Day mattress sales. The latter is when people slowly start spending again following the January lull, and retailers look to stoke interest with strong offers and prices that are often as low as Black Friday.
The Memorial Day mattress sales are another key time to buy a new mattress, as retailers look to make way for newer models launching over the summer by discounting older stock. For the sheer volume and variety of discounted mattresses, it's as good as Black Friday, but we've noticed prices don't always dip quite as low. You might see the same discount advertised – $200 off, say – but the price may have gone up, so while the mattress is cheaper than its previous full price, you'd have saved more if you bought it in the November or February.
The same can be said of the July 4th mattress sales and Labor Day mattress sales: discounts typically match those offered during other major holidays, but many of the prices aren't quite the lowest. They're generally still good deals though, and worth grabbing if you need a new mattress.
Here's when you shouldn't buy a new mattress if you can help it: over the summer. This is the most expensive time of the year, with prices generally at their maximum. You might see similar discounts advertised, once again, but prices can be as much as $200 more than at other times of the year.