However, itâs also a time to be aware of the dangers soaring temperatures can bring. Extreme heat is the number one weather-related killer in the U.S, claiming more than 650 lives across the nation each year, according to the Centers for Disease Control and Prevention.
1 In a bowl whisk together garlic, extra virgin olive oil, balsamic, 1/4 cup red wine, 1 tablespoon chopped rosemary, salt and pepper.  Place flat iron steak in a resealable plastic bag. Pour marinade over the top. Shake to coat steak in marinade. Refrigerate for 8 hours or overnight.
1 Marinate at room temperature about 15 minutes. 2  Prepare a grill for direct-heat cooking over hot charcoal (high heat for gas); see grilling procedure. 3  Discard marinade and pat steaks dry. 4  Oil grill rack, then grill steaks, covered only if using a gas grill, turning occasionally, 6 to 8 minutes total for medium-rare.