In this song there is a reference to Sintra that can be interpreted as alluding to the often rainy character of Sintra:
"Oh the English rain
Seems to follow me again
All the way from Sintra Portugal
It's where I met you just one year ago."
Sintra has in fact a microclimate that makes it unique in the Portuguese climate. It is often sunny everywhere and it only rains in Sintra.