The Thames Barrier is due to reopen at 6pm after high tides earlier on.
But flooding is still causing problems for people in and around the capital.
In Sunbury-on-Thames, Surrey, children's parks and river paths are underwater.
Also, some trains coming into London are delayed due to two land slips in southern England.
More top news
Londoners who have received new electronic gadgets for Christmas are being advised to take simple steps to protect them from thieves.
The Boxing Day sales got off to a flying start with shops reporting a surge in business during the first hour of trading.
Bus strikes are planned for Monday 29 December and Monday 5 January.