The climate in Lisbon Portugal is one of the warmest in Europe, because of the influence of the Atlantic Ocean. There is an annual average of 3300 hours of sunshine, which makes it a year-round destination.
Springtime is a good time to pay this city a visit, because temperatures are mild. Also Fall brings pleasant temperatures, which makes May through September (even October) the best time to visit. But keep in mind summers can be hot here, with temperatures that go over 30°C (86 F).
Winters are mild with a temperature between 8°C (46 F) and 15°C (59 F). However don’t forget to bring your umbrella in the winter, spring and late fall!
I have to say when I was there in mid October, I still had temperatures in the higher twenties (upper eighties). So, with a bit of luck, you’ll have great weather in Lisbon 🙂