Severe to extreme heatwave conditions are expected across the ACT this week, with the ACT Emergency Services Agency warning residents to prepare and take precautions as temperatures climb.

The heatwave is expected to peak later in the week, with daytime temperatures reaching the high 30s and overnight minimums rising to the high teens and low 20s. The Bureau of Meteorology is forecasting 35° on Wednesday 7 January, rising to 37° on Thursday and peaking at 39° on Friday, before Canberra set to swelter as Summernats crowds roll in38° on Saturday and cooling to 27° on Sunday.

The warning comes as thousands of people are set to attend outdoor events across the city, including Summernats, prompting reminders to take extra care in extreme heat conditions.

Summernats organisers say a range of measures will be in place to help patrons cope with the heat. In addition to ice, the festival will feature misting stations pumping out cool, moist air, shaded areas and water refill stations across the site. Around 50,000 Zooper Dooper ice blocks are set to be handed out, with additional water available in hot spots such as queues.

Residents are being urged to prepare now to manage the heat, remain alert to the risk of heat-related illness, and plan ahead to keep themselves and others safe.

Heat can make anyone sick, but some people are at higher risk. Those most vulnerable include people aged over 65, very young children, people with pre-existing medical conditions, and anyone working or spending extended periods outdoors.

Heat-related illness can range from mild conditions such as rashes or muscle cramps to heatstroke, which is life-threatening.