ロッテルダム 8月の天気

A July/August trip report on the Utrecht forum reads like a checklist for exactly this month: warm, sunny days good for sitting out at the canal-level cafes, easy biking and boat-trip weather, and a city that stays noticeably calmer than Amsterdam an hour away even in high summer. The same report notes a few showers rolling through mid-stay, so a light layer stays useful. August's record backs both halves of that: 23.6C days, 12.9C nights, 63mm of rain across ten days, 10.8 hours of sun and an AQI of 47 - a genuinely comfortable, lightly touristed month.

Forum posters describe January across the Netherlands, Rotterdam included, as capable of almost anything - temperatures anywhere between -15C and 15C, with varying degrees of rain, snow, or clear skies possible on a given day. Posters consistently recommend a proper winter coat, hat, scarf, gloves, warm sweaters and genuinely warm, weatherproof footwear regardless of forecast. Posters are direct that snow isn't guaranteed, and even when it does fall it typically doesn't stick around for long. Posters generally caution that forecasts here are only reasonably reliable about 2-3 days out, so treating a longer-range prediction as certain is a mistake. Posters generally rate January as workable for a Rotterdam visit with the right packing, but genuinely unpredictable day to day.

The Dutch line the forum keeps quoting for July is "if you don't like the weather, just wait five minutes" — and the numbers bear it out: around 22°C on average, but posters describe 28°C one day and 15°C the next, and sunny mornings turning to thunder by the afternoon. Rain lands on about thirteen days. Layers plus a small umbrella or poncho is the standing advice, with a big thin scarf as the adjustable extra. July is also crowded and pricier once the school holidays start. Rotterdam-specific: the bike paths, the harbour boat tours, Delfshaven and the water taxi all survive a shower.