i HAVE MY DOGS TRAINED TO GO OUT SIDE AND POTTY

. MY BOY GOES INSIDE TO POOP BUT NOW THAT IT IS COLD OUTSIDE AND IT JUST SNOWED A COUPLE OF INCHES HERE IN MICHIGAN THEY DON'T WANT TO GO OUTSIDE

.WHAT CAN i DO? MY BOY LIFTS HIS LEG OUTSIDE BUT DOES NOT WISH TO PEE INSIDE

AND MY GIRL HAS ALWAYS GONE OUT SIDE(I DIDN'T HAVE HER AS A PUP) HOW CAN i GET THEM GOING BACK INDOORS WITHOUT PULLING MY HAIR OUT!