Electricity Costs -- NYC -- During The Late Summer Heat Wave -- August 28, 2018

Link here for New York state and NYC. Click on the area of the map that interests you.

ISO New England, a bit farther north, see graphic below, link here. And, yes, it will cost $300/MWh if one chooses to do laundry at noon. From wiki:

In the U.S., it costs approximately 45 cents to dry a load of laundry in an electric dryer, based on a 5,600-watt dryer, 40-minute run-time, and a 12-cent-per- kilowatt-hour rate. A kilowatt-hour (kWh) is equal to the energy of 1,000 watts working for one hour. 

My math suggests at $300/MWh that same chore will cost about $1.00.

Air conditioning?