Conditions are great for surfing this week around the Bay of Plenty, and for some a chilly dip in the sea is a welcome start to a winter's day. But unseen dangers lurk too.

Surfers will be delighted to find that Mount Maunganui, Tay Street, Maketu and Matakana Island have surf swells up to 1.9 metres today, with a good swell around until about Thursday. At Waihi Beach the swell height is around 2.2 metres today.

'Good quality surf, long swell period, little or no wind, and swell height greater than a metre,” says a MetService spokesperson.

Whakatane, Hawai and Maketu are listed as the three top surfing locations today on the MetService Bay of Plenty Marine website.

Surf crashing in on the rocks around Mauao on Monday morning. Photo: John Borren.

Sea temperatures across the Bay of Plenty are 15-16 degrees Celsius and a 4/3mm wetsuit recommended for surfers.

'Conditions are great for surfing! And for some – a refreshing, rejuvenating dip is the perfect way to start the day! Although it's not Fiji temperatures!” says Surf Lifesaving New Zealand Eastern Region lifesaving manager Chaz Gibbons-Campbell.

'We have seen a number of polar plunges take place over the last few weeks and it's great to see so many people out supporting some great causes.”

Chaz says cold temperatures can catch people off guard and make them less capable in the water.

'Hypothermia is a real risk so make sure you are looking after yourselves.”

Safety messages Chaz wants people to be aware include understanding how rips work, knowing your limits and not swimming alone.

'Lifeguards are not on patrol at the moment but our safety messages are still very important.”

Safety advice from Chaz:

Know how to spot rip currents and better still, how to escape a rip current.

'There are some great tools online which can educate people on rip currents. Those in shore holes we talked about during summer are still there is winter.

'Never surf or swim alone – at the very least tell someone where you are going and keep them updated if plans change.”

Chaz says to know your limits.

'Check the conditions before you head out. If paddling out in big surf is not something you normally do then maybe wait for a calmer day.

'Lastly, make sure you have some warm clothes tucked away and a nice shower nearby to warm up afterwards.”

What is a rip?

A rip current - often called a rip - is a narrow body of water moving out to sea. These pose a risk to swimmers as they can sweep people out to sea quickly.

Rips are caused by complex interactions between the sea- tides, waves, currents - and the shape of the shore bed. As waves travel from deep to shallow water, they eventually break near the shoreline. As waves break, they generate currents that flow both offshore - away from the coast - and alongshore - along the coast.

The larger the surf, the stronger the rip current.