Weather at Night

Can someone please tell me what the weather is typically like at night in Puerto Vallarta in March/April. My b/f and I are going the week of March 24th and I would like to know what I should bring to wear! I traveled to Riviera Maya mid Feb and was unpleasantly suprised at how cool the nighttime temps were. I was expecting to be able to wear tank tops and shorts or a strappy dress but I ended up freezing.
Any info as to what to expect would be greatly appreciated!

I take one long sleeve item (very lightweight black silk knit cardigan works nicely). I rarely use it, but have on occasion. for evenings I like long, loose, lightweight (palazzo style) pants, tank top, sandals.
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OPIATE REHAB ADVICE

Because me and tyler spent alot of our evenings along the malecon I wore a light sweater over a tank top and it was perfect.

I occasionally put on my capris with a t-shirt and was just fine but my sister is a little cold blooded and had her jeans and a light sweater on most evenings. I guess it depends on how cold you are normally. Just remember that after being in the sun all day it kind of hurts to put things on your shoulders!!! :D

Thanks to everyone who replied to my post :D

Good information....... and about not over packing... Impossible!! I ALWAYS do! A girl has to have choices, you know!