Environment Canada has issued a heat warning for central and eastern parts of the province this week.
The national weather agency said temperatures are expected to reach 30 C on Tuesday and Wednesday, with humidex values making it feel more like 33 to 38 C.
New Brunswick's Department of Health has issued a level one heat alert for the next two days.
The heat alert has been issued for several areas across the province including:
- Fredericton and southern York County
- Oromocto and Sunbury County
- Grand Lake and Queens County
- Woodstock and Carleton County
The Department of Health wants people to be aware extreme temperatures are on the way so they can avoid or mitigate potential health risks.
Level one is the lowest level of warning.
At level one, the province warns "certain vulnerable persons may be affected" by the heat.
They can include young children and older adults, people who have health conditions or use certain medications, and people who are homeless or socially isolated.
Level two is considered a high heat alert and everyone is at an increased risk of heat stress and heat stroke.
An extreme heat alert comes in at level three, and everyone is at a high risk for heat-related illnesses and heat stroke.
Drink lots of water
Environment Canada is warning residents to take precautions, including drinking plenty of fluids and keeping out of the sun.
Residents should also be cautious of symptoms related to heat illness such as dizziness, fainting, nausea, vomiting, rapid breathing and heartbeat, extreme thirst and decreased urination with unusually dark urine.
Prepare for rain
Meanwhile, overnight temperatures will hover around 18 C, providing little relief from the heat. The weather agency said temperatures will be cooler along the coast where southwest winds blow onshore.
"Elsewhere in New Brunswick, temperatures and humidity levels are forecast to remain just below warning criteria," Environment Canada said.
The weather agency said temperature and humidity levels will decrease Wednesday night into Thursday, as a cold front sweeps across the province.
Wednesday night will also have a chance of rain and thundershowers.