Well goodbye Winter and hello Spring.
From an astronomical viewpoint, today is the first day of Spring. At 4:57pm (16:57UTC) the sun will cross the celestial equator and, for the next 6 months, shine more on the northern hemisphere than on the southern hemisphere. This happens each year on March 20th or March 21st; it varies due to the fact that the length of a year is not exactly 365 days. On September 22nd or 23rd the reverse will happen on the Autumnal Equinox.
Strangely though, the weather forecasters have been claiming it is already Spring, ever since the 1st of March. This is because the Met Office has decided to use its own definition of Spring to make things easier for themselves.
So, put away your winter duvet and start slathering on the sun cream!