We went in December and it was cooler than now, didn't need coats or jumpers at all so it depends what you're used to.
There's great restaurants, The Little Elm, fantastic home cooked English food, La Cabana in Macher is lovely, Mardeleva on the harbour for seafood, My Kitchen Julius for steaks and meats. We go every December and love it, we stay at the other end of PDC towards Los Pocillos and Matagorda.
Puerto Calero is lovely and you can walk from PDC, there's some zig zaggy steps just past the marina, if you go up those it takes you onto the coastal path. It's a fair walk and a nice one but take lots of water with you. You can also walk the opposite way, past the airport, through Playa Honda and through to Arrecife, long walk but plenty of places to stop for drinks etc., or you could hire bikes.
If you're there over the weekend you could go to the market up in Teguise town on Sundays, quite cheap if you get a bus up there and there's loads of stores - some selling cheap nasty stuff but others selling leather, artisanal stuff, jewellery etc. Also a couple of decent food places there and it's quite a nice town with a lovely square where you can sit and chill - I'd recommend getting there early though as it does get very crowded