Candlestick Park was known for being very windy and Montana seemed to handle it.
They're totally different. The winds at Shea were stronger and they swirled constantly, often changing directions from play to play. The winds at Shea were often artic like too.
Also, Montana wasn't in a real vertical offense, he'd dink-dnk it and Rice, Taylor and the (Brett something) would run it in. Joe Willie was throwing it DOWNFIELD.
I'll put it this way, JN could throw any pass that JM could throw, but JM could only dream of throwing some passes that JN could throw.
In other words, switch them around and JN would have 4 rings, while JM would have none. I'm not knocking Montana, he was a great QB, but he was very fortunate to wind up with Bill Walsh in that offense and with that great supporting cast. Put JN with that 49er team and he would have had similar, if not better results. It would have been a waste of an incredible arm though.