It says humidex values are expected to approach mid-30s today and Friday.
A warm and humid air mass over the island will produce high humidex values that could reach or exceed 35 Celsius over inland areas of eastern and Northeastern Newfoundland this afternoon. The weather office says although not expected to reach warning criteria (40 C), peak humidex values are likely to remain near or above 30 for the next several days.
Under these conditions, the public is advised to be cautious when performing strenuous outdoor activity and to drink plenty of liquids, especially water, to avoid dehydration.
There are also fog advisories for Avalon Peninsula southeast and southwest, Burgeo-Ramea and Burin.
The humid air mass and southwesterly winds are expected to result in a prolonged period of dense fog extending from Burgeo to the southern Avalon Peninsula.
Environment Canada says the fog is likely to retreat towards the coast during the day and spread inland again at night. These conditions could persist for several days.
Visibility may be significantly and suddenly reduced to near zero. If travelling, be prepared for areas of near zero visibility.