Large bodies of WATER tend to moderate the climate of surrounding areas. (This is why you often hear people say there is a cool sea breeze or it is colder by the water).
MOUNTAINS block the flow of moisture laden air and THE RAIN SHADOW effects causes dry areas and deserts to develop.
Here’s the background to help you understand these concepts. A rain shadow is a dry area on the side of the mountain that does not get direct wind. It’s the leeward or opposite side of the mountain from where the wind is hitting the mountain. The side that the wind hits is called the windward side. When moist winds blow toward mountains, they are forced to go upward. Where does the moist air come from? Many possible sources but it is frequently from the ocean or other large body of water. The water evaporates into the air, making the air moist. The cool air from the ocean can cause a sea breeze. That is when the moist air from the ocean blows toward the land. That sir is often cooler because the land changes temperature more easily than a large body of water like an ocean. The ocean gets cold overnight when the sun is down. But it takes longer for the ocean water temperature to warm up the next day — longer than for the land to warm up and the air above the land.
I hope this answer was helpful. I really enjoy helping students improve their understanding of geography,
weather, and earth science along with other subjects that I tutor. I also like seeing students increase their own confidence. Best of luck to you!