I hope you can get some on the grill before grilling season is over. The overnight brine/marinade is the key to succulent chicken, and the BBQ sauce gets put on at the end of grilling for just enough char.
Summer BBQ Chicken
Marinate overnight in the fridge:
3-4 lbs. chicken parts, bone in, skin on
1-2 cups thin yogurt, kefir, or buttermilk
1 Tbsp. salt
At some point, mix up the BBQ sauce in a small saucepan:
1 cup ketchup
1 Tbsp. olive oil
1/4 cup white vinegar
1/4 cup brown sugar
2 Tbsp. paprika (bonus if it's smoked!)
1 Tbsp. chili powder
2 tsp. garlic powder
1/2 tsp. cayenne, or to taste, optional
Simmer sauce for 5-8 minutes. Cool. Keep in jar in fridge. Enough for 9 lbs. chicken or for other recipes. (You could probably use commercial BBQ sauce - I don't keep it on hand.)
So, back to the marinating chicken. . .
Thirty minutes before grill time (about 1 hour 10 minutes before you want delicious hot chicken), drain off and discard marinade. Allow chicken to sit at room temp for 30 minutes.
Preheat grill to 400F. Sear chicken pieces on each side, about 3-4 minutes a side.
Turn heat to low/med and grill for 30 minutes without flipping or peeking. Turn pieces. Brush topside with BBQ sauce. Continue to grill for 5 minutes. Flip pieces. Brush topsides with BBQ sauce. Grill 5 more minutes. Done!