מזג האוויר בCosta da Caparica (Caparica) בספטמבר

Regulars are specific that mid-September is a genuine turning point for crowds rather than weather: Portuguese and Spanish schools go back around then, so visitor numbers drop noticeably even as the weather itself stays warm and sunny through the month. Our row backs the pleasant, still-summery read, 27.2C reading as a real 27C, over 18.1C nights, with rain minimal at 23.9mm across 3.2 days. Regulars are consistent nights cool down enough that AC isn't really needed, a genuine comfort upside over the peak summer months. The sea sits at 19.1C, on the cool side but manageable. The record: humidity 73 percent, 10.8 hours of sun, a 22.2 kph wind and AQI 38.

Lisbon-area forum threads describe January as running around 15C in the day and 7-10C at night on average, with real variation depending on the day - a sunny stretch can reach the high teens C, while a grey, rainy one might barely clear 10C with nights near 5C. Posters recommended warm layers and sturdy, non-slip footwear, since wet cobblestones are a genuine hazard on rainy days around the wider Lisbon coast. Costa da Caparica, just across the river, follows this same general Atlantic winter pattern rather than anything milder or wetter.

Forum posters describe a steady, pleasant Atlantic breeze here that keeps July temperatures from feeling too intense, though it also means the ocean itself stays genuinely cold - posters describe water temperatures under 20C even at the height of summer, more suited to surfing (with a wetsuit) than casual swimming. A light jacket for evenings is standard advice despite the warm days. Posters flag a practical logistics point for anyone coming from Lisbon: bus traffic to and from Costa da Caparica gets genuinely heavy in summer, so a trip that normally takes around 30 minutes can run considerably longer during peak July-August crowds.