For Californians the "season" is year round. Our only issues with weather are snow in the mountains where flea markets aren't a thing anyway. The rainy season is January through April, but it's an inconsistent thing. Our water supplies largely come from mountain snow melt.
Anyway, too bad you didn't have your better boxes with you, but the outcome helped out anyway. When I started doing flea markets in 2004 a "slow" day was $300. Now (recession years later) I'm happy to even DO $300 with $200 being a more normal day and $100 days aren't rare. I don't sell anything much bigger than a breadbox at the flea.
It all depends on things like what you've got, the crowd, the venue, time of year, time of month, etc. There are 4 flea markets within 10 miles of each other and they represent different opportunities. I only sell at one of them.
Used to be you could get $75 for a lightweight worm drive circular saw but now it's a hard-sale at $40. No construction going on around here.
The dollar by dollar gathering has been more and more common here especially the last year or so. Some days a $10 sale is my biggest ticket. I took out a $125 (retail) Pelican case about 4 times before I finally sold it for $45 (came down from $60). There are lots of stories like that.
BUT, the flea gets rid of stuff that isn't viable on Clist or eBay, so what can you do. Try selling a Pelican case on eBay...look at the competition there.