The great news about our weather is that on the average, the daily percentage of hours with sunshine is over 60% – even the lowest month´s average is near 50%. Add to that the fact that even during the rainiest winter months, more than half the days are without precipitation, and you have near perfect weather for walking!
The average monthly daily high temperatures range from 15ºC to 29ºC and low between 9ºC and 17ºC. It is rare for the daytime temperatures to rise much above 30ºC or the night temperatures to go down to negative degrees. As we are in Southern Europe, our warmest months are July and August, coldest months are Dec to February. When it rains, it rarely rains the full day or several days in a row. Rainfall varies greatly according to the areas of Sintra: the mountain receives an average of 1000mm of rain per year, and the nearby plateaux only 400mm.
There is a microclimate in Sintra as the cool Atlantic air meets the warm Mediterranean air. This is the reason for the typical mist, sometimes felt in the summer mornings and ends of afternoons; and the reason the nights are cool, even in the summer months. The air can be quite humid due to the closeness of both the Atlantic Ocean and the breathing of the lush vegetation of the mountain. This is also the reason why in the summer months the Sintra temperatures don´t rise much over 30º and can be up to 5º less than in the neighbouring Lisbon.