The Met Office has declared a Level 2 heat-health alert and forecasts the hot weather conditions to continue until 6pm on Thursday.
The highest temperatures are likely to occur on Wednesday, July 20, the forecaster has said.
The temperatures for heatwave in the South East are expected to be 31°C during the day and 16°C overnight.
West Sussex County Council (WSCC) is encouraging people to keep an eye out for anyone who might need help maintaining their health and wellbeing or struggle to cope in the hot weather.
High temperatures can be dangerous, especially for the very young, elderly, or those with serious health conditions. In particular, very hot weather can make heart and breathing problems worse.
Christine Field, cabinet member for community wellbeing at WSCC, said: “While many of us look forward to warm summer weather, heatwaves do come with a health warning.
“The health effects of intense heat can come on very quickly. So please enjoy the sunshine, but do so safely, and keep an eye on anyone you know who may struggle to cope. Make sure they are keeping their home cool, drinking plenty of water and not doing any strenuous activity, particularly avoiding the sun during the hottest part of the day.”
Tips to cope with the weather
West Sussex County Council has released the following advice to help keep residents cool.
• Avoid getting too hot in the first place – keep windows closed if it is cooler inside, close curtains or blinds
• Check your home’s thermostat or thermometer to see how hot your home is getting
• Have plenty of cold drinks and avoid alcohol
• Have regular cool baths and showers
• Avoid being outside during the hottest part of the day (11am to 3pm), stay in the shade and avoid strenuous activity
• Wear appropriate cool, light clothing and a hat
• When going outside, make sure you and your family use sun cream at all times to protect your skin.
Anyone worried about their health during hot weather or a heatwave, especially if taking medication, feeling unwell or having any unusual symptoms such as cramp in arms, legs or stomach, weaknesses or problems sleeping should contact their doctor, speak to a pharmacist, or call NHS 111 or visit the website at www.nhsdirect.nhs.uk. Alternatively get a neighbour or friend to help you get help.
For more information about hot weather and health visit www.westsussex.gov.uk/living/emergency_services/preparing_and_dealing_with/severe_weather/heatwave.aspx