Meteo Olbia (Costa Smeralda) in agosto

August in Corsica is the month the forum warns about rather than recommends. The island's population goes from roughly 280,000 in winter to about a million in August, Bonifacio itself gets described as gridlocked, and the small coves fill to the point that regulars call the popular beaches unusable. The heat is the other half of it - high 30s, with nights that do not cool. Wind is the mixed blessing: it takes the edge off, and late August can blow hard on the west and north-west coasts and through the Bouches de Bonifacio, so beach choice becomes a question of waves and flying umbrellas. June and September are what they suggest instead. The record: 32.3C days that feel like 36C, 20C nights, 1.8 precipitation days, 12.6 hours of sun and a 24.9C sea.

Sardinia's forum describes January as the island's coolest month but genuinely variable - some posters had lovely sunny days with cold, clear nights (no cloud cover to trap any warmth), while others visiting in the same general window hit cold, wet and windy stretches instead. A clear midday can reach a pleasant high-teens C before dropping off fast into the afternoon and evening, but freezing temperatures are unlikely on the coast around Olbia. It's not remotely beach weather, but a mild, walkable winter month when you catch the good days.

Forum posters describe July around Olbia and northern Sardinia as very pleasant for swimming, with daytime temperatures usually above 30C and sea temperatures around 24-25C, though posters flag a real risk of jellyfish this time of year. Posters consistently recommend packing a light wind or rain jacket and a light sweater for the evening despite the summer heat, since coastal evenings can turn noticeably cool. Posters also note Sardinia runs windier in summer than other seasons, a real factor for anyone planning beach days or boat trips. Posters generally rate July as calmer and less crowded than August, making it their preferred pick between the two peak summer months.