Kauai is beautiful. North shore does get more rain but it is less crowded than Poipu area. that being said, we have never been stopped by any rain on Kauai and we have been there 12 times. Guess we are very blessed. it will rain just about every day at some point. Each season has its beauty but winter will be cooler and more rain. Never been concerned about poisonous bugs or snakes and frankly have never seen a snake! renting on the beach, perhaps Hanalei for North shore or Anini beach would be a good place, Poipu for south shore. Try VRBO for some good rentals and prices. Do you mean right on the beach or ocean view? Lots of condo's with fab ocean views but not necessarily right on the beach. We love Poipu Luxury (2 bedroom 2 bath) at the Makahuena properties (VRBO) which sits right on the lava rocks with nothing in front of you but ocean and waves crashing on the rocks but no beach.

What people forget is even though there is rain it isn't constant and it's still tropical and warm. And by cool in the winter - means it could drop down to the mid 70's. (Actually that is perfect weather as far as I'm concerned ) Plus the rain produces the beautiful rainbows you'll see over the mountains, and the shockingly green lush landscape! I love the North Shore of Kauai there is no place like it. The Southern part of Kauai is nice but dry and not as lush. However, the island is pretty small and you can drive from one end to the other is a very short time. I've never seen snakes or bugs.

More likely to hear chickens than get bit by bugs on Kauai. And as Nanabee says - it's beautiful after a rain on the North Shore - including many waterfalls streaming down the hills.

Kauai is my favorite island also. Love the North Shore but April is a transition month and you might not be able to swim up there, if so, just drive down to Poipu. Or you could also stay in Poipu if you want. For the North Shore, I like Hanalei Bay Resort - just be sure to rent from an owner and not the hotel, as the are starting to renovate the hotel and timeshare rooms. Beautiful pool.
For South in Poipu, I'd look at either Kiahuna Plantation or Poipu Kapili.
Be sure and book your rental car when you book airfare, as they can and do run out. I use this outfit:
discounthawaiicarrental.com