It depends.
The problem with any forecast where you tell it a postcode and it tells you the weather for the next few days is it makes no indication of what might actually be happening. Is that rain at lunchtime in two days time a big front traveling slowly across the country in which case its going to rain at some point. Is it warm front (and thereofre just showers), or is it a fast moving front being dragged out and could easily pass north or south of you and you never know. Equally the opposite, if it says sunshine, might just mean the front is predicted a few miles away or youre sat in the middle of a high pressure, you wouldnt know.
Much better off looking at the actual maps, and the isobars, which are still on the bbc website, then you can make a judgement about whats going to happen (e g is it just clouding over or is this the rain that was predicted for 5 miles away hitting us).
N.b. when the bbc app says 90% chance of rain that means anything from 90% chance of a few spots in the hour to 90% chance of it raining torrential for the whole hour. Its just a confidence level because its trying too hard to predict whats going to happen exactly at your postcode.
I trust the app enough to plan a ride in my lunchbreak or after work, wouldnt trust that sort of forcast for the next day, you need to go look at a map.
