Temperatures are rising in B.C.'s Southern Interior, prompting Environment Canada to issue a heat warning for the region.

The weather agency says elevated temperatures beginning Sunday and continuing through next week pose a moderate risk to public health.

Daytime highs are expected to reach the high 30s and low 40s with overnight lows in the high teens.

"A building ridge of high pressure over the region will usher in very high temperatures beginning Sunday," Environment Canada said Friday afternoon.

It added that heat risks are greater for seniors, people who live alone, those with pre-existing health conditions such as diabetes, heart disease or respiratory disease, people with mental illnesses such as schizophrenia, depression or anxiety, people with substance use disorders, and people with limited mobility.

"Check on family, friends and neighbours, who are at higher risk, particularly if they live alone, to make sure they have a cool space," Environment Canada said.

People are advised to watch for early signs of heat-related illness (feeling unwell, fatigue, thirst, headache, unusually dark urine) as these can quickly lead to life-threatening emergencies.

"Environment Canada and local Medical Health Officers expect an increase in health and safety risks from heat and are advising the public to take precautions."