Prevailing winds bring rain
Rain depends, in general, on two things: which direction does the wind come from, and does that wind have rain in it.
Mountains work by removing rain from winds in a certain direction. If the winds generally move south to north, then places to the north of a mountain range are dry. This is the case with Uzbekistan in Central Asia, blocked by the mountains of Iran and Afghanistan from wet winds from the Indian Ocean. For a counter example, Nebraska in the US is in the middle of a continent, like Uzbekistan, and north of a tropical ocean (the Gulf of Mexico). But unlike Uzbekistan, there are no (significant) mountains between Nebraska and the Gulf of Mexico, so warm summer winds penetrate into the continent. Nebraska is a fertile prairie, while Uzbekistan is mostly a barren desert.
So the real question for you is, where do the winds come from, and are they wet?. That is up to you. Look at wind maps of Earth, and decide where on the planet your location is. Then you can copy the local wind patterns for the appropriate latitude and location on a continent. Once you have the wind patters, see if those winds come from an ocean, or across a mountain range. Winds off of warm oceans cause monsoonal rain; winds across mountain ranges carry little moisture; other winds are somewhere in the middle.