MY
That has been standard practice for some time. Blue for cold (below 2 or 3 C), green for chilly, yellow for normal, orange for warm.
It even occurred under the old system, although there were just 3 colours - Blue for up to 0, yellow for 1-25 and orange for 26 and over
DOUBLE EDIT: Didn't realise the colour on the temperature symbols were always varied on the website. Wonder if that will come to the telly forecasts too.
That has been standard practice for some time. Blue for cold (below 2 or 3 C), green for chilly, yellow for normal, orange for warm.




It even occurred under the old system, although there were just 3 colours - Blue for up to 0, yellow for 1-25 and orange for 26 and over
This may just be me being desperately thick here, but what determines which symbol is shown in the new system? In this example, a 26% chance of rain at 1600 gets a cloudy-with-sun symbol, and a 26% chance at 1900 gets a rain symbol. Am I alone in finding that a little confounding? Is it to do with the duration of rain forecast within the hour?

1900 is after sunset, 1600 is before.
BR
Been waiting ages for Spring to finally arrive.
Keep your eyes peeled to the TV on Tuesday lunchtime

Been waiting ages for Spring to finally arrive.
Be nicer and more tolerant to each other. Them's the rules.
CC
Potentially so bluntly as to make it a problem.
Well that problem's been solved in a fairly blunt way.
Potentially so bluntly as to make it a problem.

It even occurred under the old system, although there were just 3 colours - Blue for up to 0, yellow for 1-25 and orange for 26 and over
Indeed, I'd obviously become blind to it.
I think it was the moving the colour away from being obviously associated with the temperature digits that seems to have thrown me, but I like the inclusion of the at-a-glance colours and I'll get used to it. I like the cleaner feel of the website already, but it will be better when the video forecasts are reintroduced.