The busiest travel months in Europe are traditionally July and August, which align with the peak summer holidays for both international tourists and Europeans themselves. During this time, popular destinations like Paris, Rome, Santorini, and Barcelona see their highest crowds, highest hotel prices, and hottest temperatures. In 2026, a notable trend called "Super September" has emerged, where September is increasingly rivaling the summer months in popularity as travelers seek to avoid the extreme heat and peak crowds of August while still enjoying pleasant weather. May and June are also very busy "shoulder" months as they offer ideal temperatures for sightseeing. Conversely, the winter months of January and February are the quietest, except in ski resorts. If you plan to visit during the July-August peak, it is essential to book "timed entry" tickets for major landmarks like the Louvre or the Colosseum months in advance to ensure you aren't stuck in lines for hours under the summer sun.