I've spent extended periods of time during 3 Xmas seasons in San Pedro and the bug level was a bit different each time. It depends on how much wind there is and how much it has rained and such. It was also worse on the back side of the island and on the road down south. Keep in mind that at those times I found myself virtually overwhelmed with skeeters, it was also dusk.
So the thing of it is, it could be bad or it could be not so bad. Regardless, I always sprayed myself quite liberally with a high percentage DEET product. The percentage after around 27.5% is sufficient to do the trick, however, while a higher percentage will not give you any better coverage, it will give you a longer duration of coverage. And so you may not need to reapply if out for the evening.
What's more often worse are the sandflies. Little buggers nip your feet and ankles and lower legs and can work their way up from there. So, to thwart that, I make sure that I'm good and oily on my feet and lower legs. The oilyness can help to keep them from biting because they drown in the oil, so to speak. Then a light spray on the arms and into my hands to apply lightly to my face and neck. Wash your hands after applying, so that you don't accidentally get it into your eyes (by rubbing) or in your mouth by whatever.
I've had friends that used citronella and skin-so-soft products. At the end of the stay, I had a few bites and they looked like they had chickenpox.
Having said all that, I use the same system when there at other times of the year, as well. Works pretty well for me but when it doesn't and I end up with an itchy welt or two, I take a couple of spoons of Benadryl and put cortizone cream on them. Fixed up in no time.
You also want to treat your DEET with respect. It will melt nailpolish, some fabrics and varnish on the furniture. Keep your bottle in a ziplock baggie.
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