The seasons in Portugal follow the same calendar as most of the northern hemisphere.
Here are the approximate start and end dates for each season in Portugal:
Spring
Spring begins around March 20th and ends around June 20th. During spring, temperatures begin to rise, and flora begins to bloom.
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Summer
Summer begins around June 21st and ends around September 22nd. It is the hottest season of the year in Portugal, with high temperatures and long sunny days.
Autumn
Autumn begins around September 23rd and ends around December 21st. During this season, temperatures begin to gradually drop, and the leaves on the trees change color before falling.
Winter
Winter begins around December 22nd and ends around March 19th. It is the coldest season, with lower temperatures and, occasionally, the possibility of snow in the country's mountainous regions.