Lisbon in general experiences a usually mild climate. You are sure to witness regular sunshine and the snowfall is quite rare. The hottest month of Lisbon weather is August, with an average of 28 degree Celsius. The evenings are balmy and mild, causing people to congregate in the main squares and pavements. In general Lisbon experiences very less rainfall and two main seasons which are summer and winter.
Summer: Summer generally begins towards the end of March and goes on up till September. Summer months are from June to August and this is the peak season when Lisbon sees a large number of tourists.
Winter: October is when winter arrives and it gets really cold in December. So, remember to carry adequate winter wear. However, a sea breeze can make the air feel a little cooler. The coldest months in the year are December and January with daytime temperatures of about 14 Degree Celsius. This is also a good season to enjoy the winter activities in Lisbon.
Although weather in Lisbon is pleasant all around the year, the summer months of June, July and August are the best time to visit Lisbon to take full advantage of the coast.