The weather will do whatever it decides. We all know the range of possibilities in the UK. It may well rain or at least drizzle. There could be an overcast sky. Ther's an outside chance of sun and a likelihood of wind. Frosts maybe in winter and high humidity in the summer. It's not like Jamaica, where you have a hot sunny day until three o'clock. Then there's a tropical storm with lashings of rain to clean the air. Then back to sun, which disappears abruptly at nine in the evening. It's vague here. Which means conversations about it are trifling.
So don't waffle about weather in your writing. But use it to add mood and atmosphere. Have depressing skies or shafts of illuminating sunlight or biting winds or blankets of snow to create an apt setting. It can help to paint your picture.
But don't have inches and inches of dialogue about weather, unless absolutely crucial to the plot or characters.