The Senda Litoral from Porto, Portugal to Santiago de Compostela, Spain has mostly sunny weather in September, but sometimes there's rain too.
Porto and nearby towns like Vila Chã, Póvoa de Varzim, and Marinhas are mostly sunny, sometimes cloudy and with a bit of rain. The average high temperature is around 26°C and the average low is around 17°C.
In Viana do Castelo, Caminha, and Porto Mougás, it's usually sunny too but it can rain more than in Porto's area. Average temperatures range from a high of 24°C to a low of 16°C.
In Saians, Redondela, and Pontevedra, the weather changes more. There's mostly sun, but sometimes there's rain, cloudy days, and even heavy rain. High temperatures around 24°C and low temperatures around 15°C are common.
In the last part of the route, through Caldas de Reis, Padrón, and Santiago de Compostela, the weather can be anything from sunny to overcast, partly cloudy, to moderate or heavy rain. There can also be fog, especially in Padrón. The average high and low temperatures range between 24°C and 14°C. There's usually more rain in Santiago De Compostela, up to 6 mm/day.
In general, if you plan to walk this path in September, you should be ready for mostly sunny weather, some rain, and different temperatures.
Would you like me to add a new feature to the app? Or did you notice that something isn't working the way it should? Please Let me know!