Wipsey

In my world some parts of it won't have rain when it is raining. For example, maybe some chunks/areas will have rain all around it, but it's not raining specifically in that chunk. Sometimes it is just single blocks. This could really mess me up though because if I am, say using a riptide trident, I could come across an area with no rain and just fall to my death. Anyone know what could cause this or a solution?