I just looked at accuweather and got the mean highs and lows for Brooklyn for those days. The mean high is 81.66F. The mean low is 61.8F. I'm not sure how you get the mean temperature considering it would be lower than the high for most of the day.
If you then average the high and low you get 71.73F.
Another thing to consider is that stab wounds would speed decomp.
Thank you! The article says advanced decomposition at 16 days if the temp is above 25C, or 77F. The cooler 71.73F temp would mean slower decomposition. Instead of 16 days, perhaps 23 days?