This (below) is my online weather forecast page; you might possibly use the same service, or at least something very similar.
It tells me just about everything I need to know about the day's weather, as well as plenty of stuff I really don't need to know.
It tells me about the UV index, the hours of Sunrise and Sunset, the Dew point, Barometer readings, and all sorts of other things.
But from my personal point of view, it misses-out on possibly the most important piece of advice; and that is WHAT TO WEAR.
Ever since I can remember I have been completely useless at equating clothing with weather. On hot days I will be sweltering under several layers of ice-breaking South pole insulated coats, and on cold days I venture out in shorts and T shirt. I simply get it wrong. Occasionally I ask advice from 'she who knows everything', but my question is usually greeted by some flippant comment about going outdoors to look for myself.
What I really need is this....
5C, light rain.... Raincoat, hat, umbrella, gloves, scarf, wet weather shoes.
32C, sunny.... Shorts, T shirt, espadrilles.
Surely this wouldn't be too hard for them to set-up.