The capital enjoyed sunny spells over the weekend and into Monday as milder weather arrived across the south-east.
Forecasters said the highest recorded temperature for the region on Monday was 15.8C in Kew Gardens followed by 15.3C in St James’s Park.
The mercury is forecast to reach highs of 18C on Tuesday - around the maximum daytime temperature for Ibiza, Barcelona and Madrid.
But the good weather is not set to last with heavy rain sweeping in by the weekend.
Met Office spokesman Graheme Madge told the Standard: “We will have relatively clear skies until later on overnight when we will start to see a build-up of cloud into tomorrow morning.
“There could be some break in the cloud and a few sunny spells. On Wednesday it will be quite mild but then conditions will start to change.
“By Thursday or late Wednesday, we could start to see more rain building up in the south-east and outbreaks of drizzle.
“From midnight on Friday into Saturday, heavy rain will start to fall, setting up a pattern for the rest of the weekend when it will be really quite unsettled.
“Temperatures will be in the region of between 15C and 18C before they drop down to around 11C by the weekend.”