Portugal Temperature Map

Castelo do Neiva sea water temperature

Sea water: 19.3°C, warming slightly to around 20°C over the coming days

Waves: 1.6m

At 19.3 °C the water in Castelo do Neiva is fresh. Fine for a dip, but the first minute bites.

Sunrise: 06:57 · Sunset: 20:15 · Day length: 13h 18m

Sea temperature in Castelo do Neiva for the next 7 days

Day Sea water Waves
Friday 28/08 19.3 °C 1.6 m
Saturday 29/08 19.6 °C 1.4 m
Sunday 30/08 20.1 °C 1.0 m
Monday 31/08 19.7 °C 1.1 m
Tuesday 01/09 19.5 °C 1.1 m
Wednesday 02/09 19.4 °C 0.8 m
Thursday 03/09 19.8 °C 0.6 m

Average sea temperature in Castelo do Neiva, month by month

Month Average water
January 13.8 °C
February 13.7 °C
March 14.2 °C
April 15.6 °C
May 15.8 °C
June 17.3 °C
July 16.5 °C
August 16.2 °C
September 16.5 °C
October 17.9 °C
November 16.6 °C
December 14.8 °C

Monthly averages for 2022–2025.

This page shows the water temperature at Castelo do Neiva today and over the next seven days, so you can pick the best beach day before you go.

Sea temperature moves much more slowly than air temperature. A hot afternoon does not warm the ocean, and a windy day can cool it fast. Checking the water itself is the only reliable way to know what to expect.

Castelo do Neiva is a quiet parish south of Viana do Castelo, with a small fishing beach and the wider Amorosa sands just along the coast. It faces west into the Atlantic on one of the most persistently upwelled stretches of the Portuguese shore, so the water hovers around 16.3 °C even at the peak of summer. Rock outcrops break the sand into pockets here, which gives a little shelter from the swell but none from the cold.

Frequently asked questions

When is the sea warmest in Castelo do Neiva?

The water is warmest in October, averaging 17.9 °C, and coldest in February at 13.7 °C. This is Portugal's coldest water: upwelling is at its most persistent here and holds the warming back even at the height of summer.

Why is the water colder than the air in Castelo do Neiva?

The ocean gains and loses heat far more slowly than land, so it runs months behind the seasons. On top of that, the summer northerly wind pushes surface water offshore and draws cold deep water up in its place, which is why a heatwave on land so often coincides with a colder sea.

What can you do in the sea in Castelo do Neiva?

This is a quiet stretch of coast for walking, beachcombing and a fast swim, with far fewer people than the beaches either side of it. The wider Amorosa sands nearby pick up enough swell for surfing, and the rock pools between the sand pockets are worth exploring at low tide. Small-scale fishing still goes on from the beach.

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