But forecasters say the temperature will rise as high as 22C in the city on Thursday.
It will become increasingly warm through the week with 17C predicted for tomorrow (Tuesday), 19C on Wednesday and even warmer on Thursday.
If the temperatures hit the expected 22C on Thursday, it will make it feel unusually hot for the time of year.
Warm air is being blown over England from Africa, coming in the form of a 1,500-mile wide front of air known as the African Plume.
Met Office meteorologist Craig Snell said: “Low pressure to the west and high pressure to the east means we’re importing warmer as we go into the week, helped by the increase in sunshine.
“Next week looks pretty promising as well if you want some warmer weather. It looks pretty dry for most of the working week in England and Wales. It’s a first warm spell of weather.”
Chef Peter O’Mahoney, 21, who lives in Deal and works in Canterbury, said: “I’ve been looking forward to warmer weather for ages – especially after the winter we’ve had.
“I’ve made sure I’ve got Thursday off work so I can properly go out and enjoy it.”
There are concerns, however, that high temperatures will persist into the weekend and on to Sunday when the 38th London Marathon takes place.
In 1996 and 2007, temperatures rose as high as 25C with thousands of runners collapsing and having to be treated for heat-related illnesses.
Forecasters say today is set to remain fair with sunshine in the morning and clouds later in the day, but staying dry.
It means Kent will finish the opening game to their cricket County Championship against Gloucestershire at the St Lawrence Ground in Canterbury today.
No play had been possible on the opening day Friday because of a waterlogged pitch after heavy rain.