Issued at 2025-06-20 12:33PM ADT by Environment Canada:
Early Notification for Extreme Temperatures – issued for:
Fredericton and Southern York County, N.B. (015100)
Oromocto and Sunbury County, N.B. (015200)
Grand Lake and Queens County, N.B. (015300)

Current details:
A period of hot and humid weather is expected.
Time span: Monday and Tuesday.
Maximum daytime temperatures: 28 to 30 Celsius Monday (Humidex near 36); 31 to 35 Celsius Tuesday (Humidex 40 to 44).
Minimum nighttime temperatures: 18 to 20 degrees Celsius.

Locations:
Most of New Brunswick.

Remarks:
A combination of very high temperatures and elevated humidity will occur early next week. At this time, only marginal heat conditions are likely on Monday, but considerably worse conditions are expected on Tuesday, with air temperatures in the low 30’s and many parts of the province reaching Humidex values in the low 40’s.
Areas near the Fundy coast will be generally cooler throughout the period.
There is some uncertainty regarding the timing and extent of this event for Monday, but stronger consensus for Tuesday, and for improving conditions for Wednesday.

The next update will be issued Saturday afternoon.
Questions concerning this notification can be sent to the Atlantic Storm Prediction Centre: EC.WeatherASPC.EC@ec.gc.ca
Further alerts may be issued as the event draws nearer and the potential impacts become more certain.

More details on the alert are available here