effect of weather on flowering

does anyone know how about how the weather can affect flowering plants? say you have a plant that has about 1-2 weeks left, and the weather for that week is cloudy. will the lack of sunlight reduce the amount of potency that can be gained by leaving the plant out? i know sunlight is very important during budding, so if there isnt alot is it even worth it? what about rain? and cold nights wont help either. what i wana know is whether shitty weather will affect bud growth and thc

they will still grow and gain potency but they would be better with sunlight plus i noticed my buds starting to turn purple and different shades from the temp drop

The cloudy weather isn't a problem as far as the amount of light is concerned, that is unless your plants are already in a very shady area. The biggest problem I think late in flower and cloudy weather is the increased chance of mold in your buds because of the increased humidity. The cloud cover also will not decrease to any large degree the amount of uv light which is what helps increase the amount of resin production in the plant.
Rain is a huge problem depending on the strain you are growing. If you are growing an indoor plant outside any direct rain can be a problem late in flower especially. If you are in the ground and can't move them you need to do as much moisture maintence as possible. This time of year depending where you are can also be hard outside because of the large tempture drops at night and producing lots of dew. Has long as they are dry, under shelter at night with a fan blowing around them you should be fine.
Good Luck