Airline baggage fees are constantly changing, but just weeks after raising checked bag fees, JetBlue has introduced a new wrinkle to its policy: Surge pricing.

Nearly all major U.S. carriers including JetBlue recently raised their baggage fees by at least $5. But on Mar. 22, the airline also quietly implemented off-peak and peak season checked bag rates that can add another $5 or more to your checked bag bill. NerdWallet was the first to notice the changes.

According to JetBlue's baggage fee information page, for its off-peak checked bag rates, the airline has largely matched the industry standard, charging $35 for the first bag and $50 for the second if you're flying JetBlue's lowest Blue, Blue Basic, or Blue Extra fares and purchase your bags more than 24 hours before departure. For peak rates, those numbers jump to $40 for the first bag and $60 for the second on JetBlue's lowest fares.

As is always the case with JetBlue, you'll pay a little more to buy your bag within 24 hours of your flight. Those prices go up $5 for off-peak and $10 for peak pricing on both the first and second bags.

For JetBlue's flights to Europe, off-peak checked bags are $60 for the first and $100 for the second. The peak season rates are $65 and $110, respectively. Again, that's so long as you add your bags in advance.

So what does JetBlue consider peak and off-peak season? Well, to JetBlue, it appears 40% of the year is peak travel season. Here are the peak season dates:

April 11 29 June 20 Sept. 3 Nov. 21 Dec. 2 Dec. 19, 24 Jan. 6, 2025 Feb. 13 24, 2025 April 3 28, 2025 That's 145 total days when travelers have to fork over the extra $5 (at least) per bag. The peak calendar encompasses a good chunk of spring break, summer vacation, Thanksgiving, Christmas, New Year's, and President's Day. The blackout dates are not annual, either, meaning JetBlue will likely be deciding on its peak dates as the calendar rolls on, too.

Of all the airlines' new baggage fee announcements, this one is the toughest to swallow. Not only are your checked bag fees going up, but JetBlue has decided that the best (and usually most expensive) times of year to fly will be even more expensive if you're planning to check a bag.

Read next: JetBlue Baggage Fees & How to Avoid Them in 2024

Bottom Line JetBlue hiked its baggage fees and introduced new peak and off-peak checked baggage prices, raising the cost of a checked bag another $5-$10 if you want to fly over spring break, summer, or the holidays.

The introduction of surge pricing for checked bags into the U.S. airline market is certainly unwelcome news for flyers of the Northeast-based carrier. Here's hoping it doesn't spread to other airlines, too.