The forecast for your area is 10 C max, so it might average at 6.
There will be a moderate northerly of 20 ish mph, but as the ride is a circular, it won't make much difference; except the wind against will feel like MINUS 3. Just check WHEN you will be riding AGAINST the wind, and eat High GI ( sweeties ) accordingly.
In these conditions, you will need leggings, three jerseys, thick socks and a good pair of gloves. Wear clear lens glasses and a HAT.
My calcs say NINE hours, give or take a minute or two, and you can feast on 3500 kCals, with 3 litres of water.
Get a good 1000 kCals meal on Friday evening.
Something sweet on toast before the ride and have a 500 kCal meal at quarter distance, Repeat this at half and three quarter distance. HOT Pasties? Try and grab a banana or five as an intermediatary snack.
Bon appetite