The UK are looking evidence that the person will return back home: such as: they own a property, have a job and letter saying they will return, a local bank account with money in it, without this they will not be successful.
Rainy season finishes October, maybe with some less rain in November, Dec/Jan is fine but is winter where temperatures may drop to 20c at night, maybe more in the north. I would check a Web app for more details.