The easy way to describe the weather in Puerto Vallarta is that is boasts sunshine almost any time of the year. In fact statistics suggest an average of around 325 sunny days a year. You can also expect favorable temperatures during any season – the perfect weather for a beach vacation.
Temperatures during the summer months are around 88ºF (31ºC) with an average low of 77ºF (25ºC) while the winter months see temperatures of around 82ºF (28ºC) with an average low of 61ºF (16ºC). The great thing about Puerto Vallarta is that it never gets too hot and temperatures very rarely mean you can’t wear shorts or sit on a beach and get a tan.
There is a rainy season in Puerto Vallarta, which runs from June thru October, however, even when it rains, seldom does it continue all day. You can pretty much plan your day around when it is going to rain and you will generally always have a good part of your day with sunshine enough to get a tan.
Reference: http://weatherspark.com/averages/32587/Puerto-Vallarta-Jalisco-Mexico (retrieved 09.27.13)