The Latest on wildfires burning in the West (all times local):

7:50 a.m.

Southern California firefighters are in for another day of brutal conditions as they battle wildfires.

The National Weather Service says Monday will be the peak of the heat wave that has already brought record-breaking, triple-digit heat to the region.

Despite the conditions, firefighters report a slight increase in containment of the fire burning in rugged terrain west of Santa Barbara since last week.

The blaze is now 54 percent surrounded and remains at just over 12 square miles.

Southeast of San Diego, however, a wildfire near the town of Potrero grew by several hundred acres overnight and is now estimated at nearly 3 square miles, with just 5 percent containment.

Significant fires are also burning in New Mexico and Arizona.