bugs!!

Take some spray w/40% deet. You'll either need it or you won't but don't go without it.
It depends on the amount of rainfall. If it's been wet, you'll need it.

OFF! (with DEET) is sold in local supermarkets and pharmacies, for probably a lot less than in the US or Europe (about or less than 2 USD a small can at Palí supermarkets, for instance). So you need to bring bug spray only if you have some special natural stuff you know that works and have tried and tested before.
Have some bug spray handy, especially in wetter areas like Selva Negra. Masaya, Granada, Leon, Ometepe (and Jinotega more or less) will be dry as hell by then, so away from bodies of water there won't be any sizeable threat. And that time of the year is pretty windy too.

Mmmm...I thought that I would probably need the spray in Selva Negra. I am all about the natural stuff, but I must confess that they did not do a thing when I was in the Amazon last year. I found Off to be very low in DEET, at least in Peru. The highest I could get was 25%. Is that the case in Nica as well? I will get my own from here, just to be safe. Thank you!

The dry season begins in December. Though there may be mosquitoes (and Dolly's advice is prudent), you're heading into the best time of year to avoid them. I've been to Ometepe each of the last 11 Januarys, and saw mosquitoes only twice. Still, chloroquine for malaria protection is advised.

i was in all those places in jan/feb this year and didn't have a mozzie prob, except when hiking in selva negra. of course that's no guarantee you won't so yes, always have your chosen deet product. i also didn't use chloroquine anywhere in nica. have a fab time!

The skin so soft does nothing for me. Stick with the deet. I go to outsdoor/sporting goods places. They have the best selection. I wouldn't bother with the amleria stuff unless your going to the wilds of the Atlantic Coast. I've only used it once, and it was only for that area.

Skin so soft does nothing for me either :(. I do not know why...I wish it did. So looking forward to this trip. Thanks again everyone.