If you don't like the cockroaches, or if you have a phobia, surely one of your worst nightmares would be to be in a city that is being invaded by them, right? And it also seems that the heat wave activates them, with which in New York there are many people who surely will not be having too much fun these days.
Although you might think that these insects like high temperatures, in reality they do not. In fact, what they are doing is looking for a cooler place to protect themselves from them, as explained in DNA Info.
In New York City on Saturday, August 13, the thermometer read 36,1ºC and there was 65% humidity; on Sunday the mercury stood at 33,88ºC and there was 50% humidity. Humidity that, as explained by the professor at the University of Texas at Tyler, they like when accompanied by high temperatures.
The funny thing about all this is that cockroaches do not fly unless their life is in danger, so if the environmental conditions are not pleasant they will waste energy looking for cooler places; but they will only do it in case it is very hot and humid, since get energy through the heat around them, as explained by Dominic Evangelista, who has a Ph.D. from Rutgers and specializes in cockroaches.
Thus, they are not flying from one place to another to annoy New Yorkers and tourists who are enjoying their vacations, but rather with the sole purpose of looking for a corner or crevice that has a better microclimate for them, since, Although the heat wave is activating them, they prefer to spend hours and days in cool places.