Lismore and the Northern Rivers is about to be hit by the first heat wave of summer with three days of 35-plus degrees forecast by the Bureau of Meteorology.

The southern parts of NSW have been experiencing temperatures in the late 30s and early 40s early in the week, now it's the north coasts turn.

A typical summer pattern will see minimum temperatures increase to 19 or 20 degrees in the coming days.

There will be some relief for the weekend with the mercury forecast to drop to 30 degrees, however, the minimum temperatures will remain in the high teens.

Locations likely to be impacted include Lismore, Ballina, Byron Bay, Grafton, Lismore, Murwillumbah, Tweed Heads and Yamba.

Safety Advice

• Severe heatwaves can be dangerous for many people, especially older people, babies, children, pregnant and breastfeeding women, people with medical conditions and people who are unwell.
• Seek a place to keep cool, such as your home, a library, community centre or shopping centre.
• Close your windows and draw blinds, curtains or awnings early in the day to keep the heat out of your home.
• If available, use fans or air-conditioners to keep cool.

For information on staying safe during a heatwave go to the NSW Department of Health web page.