From National Rail:
London Overground services will operate at the reduced level of 4 trains an hour in both directions on both days as follows:
Saturday
Northbound departures from Forest Hill at 09. 17, 39 and 47 minutes past each hour from 0539 to 2347.
Southbound departures from Shadwell at 17, 26, 47 and 56 minutes past each hour from 0547 to 2356
Departures from Canada Water are 5 minutes later.
Later services available on Southern from London Bridge at 0020 and 0035
Sunday
Northbound departures from Forest Hill at 0648 and then at 03, 25, 33 and 55 minutes past each hour from 0703 to 2303 then 2318 and 2325
Southbound departures from Shadwell at 0656 then at 05, 28, 35 and 58 minutes past each hour from 0705 to 2305 then 2335 and 2343
Departures from Canada Water are 5 minutes later
Later service available on Southern from London Bridge at 2350
Southern Railways are operating their normal services all weekend so:
4 trains per hour to/from London Bridge on both Saturday and Sunday
2 trains per hour to/from Victoria and to/from Coulsdon Town via East Croydon on Saturday
2 trains per hour to/from Caterham/Tattenham Corner via East Croydon and to/from Crystal Palace on Sunday