Vatican in September

April through June and September through November offer the best balance of weather and crowds. July and August bring sweltering heat and peak tourist numbers — the Sistine Chapel becomes uncomfortably packed. December through March means shorter lines but unpredictable weather and limited daylight hours. Wednesday mornings feature papal audiences in St. Peter's Square, drawing massive crowds but offering a unique experience if you're Catholic or curious about papal traditions. Book museum tickets online weeks in advance, especially for spring and fall visits. Early morning slots at 8 AM see the smallest crowds. Friday afternoons are surprisingly busy with local school groups. Avoid the first Sunday of each month when Vatican Museums are free — the lines stretch for blocks.