Except that for July it's not been "90+". Max temps for July (Vernon, NJ for this example) more like low to mid 80s with a couple of days hitting 90. Besides, its not that simple. You need to look at temperature as well as humidity (heat index) as both affect evaporative cooling efficiency (sweating). Once the heat index is high enough, sweating will not adequately cool you down. With prolonged exposure and/or physical activity (such as hiking...), heat indices as low a 90 can be a problem. This weekend's forecast heat index is in the range of 105 - 100, solidly in the danger zone.

The other issue is the water supplies. Here in NJ, we've been getting a lot of rain, but its been in intense storm events where most of the rain drains a runoff rather than soaking into the ground. This results in high flow rates in streams and creeks - but only for a day or so after the rainfall event. From my quick survey on the AT in NJ yesterday, the larger streams are getting lower, the mid-size sources are stagnant or dry, and the smaller intermittent ones are dry - so only count on the large streams.