In A1:A100 i have various times ie 19:00, 21:00 22:00, 23:15 etc

and in column B1:B100 I have value ie 10.5 etc

I would like a formula to look up a certain time bracket in A1:A100 then in the relvant columns in B1:B100 summ the values.

So for example it would give me total value of all numbers in column B which a time hour of say 19 in column A.

Help appreciated.