Lima in September

December through April brings Lima's summer — clear skies, warm weather, and beach season. January and February are peak tourist months with temperatures around 75-80°F. But here's what guidebooks don't tell you: Lima's winter fog, called garúa, creates this moody atmosphere from May to November. Temperatures drop to the 60s, but you get fewer crowds and better hotel deals. The fog usually burns off by afternoon in the coastal neighborhoods. December and March offer the sweet spot — warm weather without the January crowds. Avoid July and August if you hate gray skies. The fog can hang around for days. But winter does have one advantage: it's dry season in the mountains, so if you're combining Lima with Cusco and Machu Picchu, June through August works perfectly for the highlands.