New Kensington 7 Day Weather. Saturday:The New Kensington forecast for Apr 08 is 47 degrees and Overcast. There is 44 percentage chance of rain and 9 mph winds from the West-Northwest. Sunday:The New Kensington forecast for Apr 09 is 58 degrees and Patchy rain possible. There is 48 percentage chance of rain and 9 mph winds from the South-Southwest.