Fog isn't the only thing causing misery on the transport system this morning: there's also disruption on the trains.
Today South West Trains said services to and from London Waterloo via Wimbledon are expected to be disrupted until 12pm, thanks to emergency engineering work to repair a broken rail.
Services may be cancelled, delayed or run non-stop between Surbiton and London Waterloo.
On the bright side South West has said tickets are valid on Southern rail...
Unfortunately for would-be Southern passengers, though, there is strike action on all its routes today, so long-suffering commuters, beware.
Despite the walkout, by the Rail, Maritime and Transport (RMT) union in an ongoing dispute over the role of guards on Southern services, the train operator has said 70 per cent of its trains will run today.
RMT general secretary Mick Cash said guard action on Southern remains "rock solid" and guards' resilience was "a credit to the entire trade union movement".
Other action planned by train drivers' union Aslef for the week has been suspended as it's in the midst of fresh talks with the train operator in a bid to avoid further disruption. It has also suspended its overtime ban.
The Tube hasn't escaped problems either - there are severe delays on the Jubilee line due to a shortage of trains. TfL has advised people to avoid using the line - tickets will be accepted on other services.
Severe Delays due to a shortage of trains, please avoid using the line if at all possible, your tickets will be accepted on the local buses.— Jubilee line (@jubileeline) January 23, 2017
Due to severe shortage of trains please use local Buses Southeastern, Thameslink and the DLR services to complete journey.— Jubilee line (@jubileeline) January 23, 2017
There's also no service between Romford and Upminster on the London Overground, thanks to a faulty train. There are also severe delays between Surrey Quays and Clapham Junction due to another faulty train in the Peckham Rye area.
Tickets will be accepted on London Underground services via any reasonable route.