The shoulder period occurs between the busy summer season and winter. It typically runs from Easter until June, and then from late September until November. The shoulder period is one of the best times for travel due to fewer crowds and cheaper flights.
May and June are excellent months of the year to visit Southern Europe as it is not yet the height of the tourist season. During these months, the weather is warm and perfect for trips to the beach, but travel is generally cheaper. It is also not as crowded.
Autumn in Europe is usually quite mild (with temperatures generally in the 50s and 60s Fahrenheit), and it is a particularly nice time of year to visit the Alps. At this time, travelers won't have to compete with the crowds of the busy summer and ski seasons.
Spring is a spectacular time to enjoy the European countryside as the alpine snow begins to melt, and the flowers start to bloom. A particularly enjoyable sight to see is the fields of tulips in the Netherlands during tulip season which begins in March.
Winter can be an excellent time to visit Europe. Ski season generally runs from December to April. Whilst it can be busy, the Alps are exceptionally beautiful at this time of year. A winter trip to Europe doesn't even mean you have to be cold; Southern Spain and Portugal is usually quite mild.