If you're running the Marathon this weekend or planning to watch from the side lines here's your guide to the day's weather.
Overall it will be dry and warm with sunny spells.
It's going to be a relatively cloudy start so may be a little chilly whilst standing around getting ready for the start.
However, things will warm up quickly by mid morning as the sun burns through the cloud.
By early afternoon in the sunshine temperatures will peak at 16C (about a degree warmer than average for this time of year).
That's good news for spectators but will mean runners will need to keep hydrated.
The good news for both spectators and runners is that there will be a gentle breeze (average 10mph).
That's enough to keep you cool but shouldn't cause too significant a head wind when running into the breeze.
It will also be staying dry so there'll be no need for umbrellas lining the course.
Good luck to everyone taking part.