Question of the Day - 26 May 2022

In the winter, at least one pool at the major resorts are kept open. The temperatures range from 78 degrees (Red Rock) up to 84 (Bellagio). The rest are within that range. 

In the summer, with the thermometer generally registering over 100 and sometimes into the hundred-teens, pool water heats up from the ambient temperature. However, pools in cities with high humidity typically maintain a water temperature closer to the ambient outside temperature. With a dry city like Las Vegas, the heat has less effect on the pool’s temperature, resulting in a cooler water temperature. 

Another reason Vegas pools are cooler is that the water pumped in from the county water system is regulated at 68 degrees. Thus, the water at most of the pools has to be heated in the summer as well as the winter. Of course, the water temperature in July isn't raised as much as in January, but even when its 110 out, 68 is a little too bracing for comfortable swimming. (If you've ever jumped into Lake Tahoe, even on the hottest day in August, you know; Tahoe's surface temperature at the height of the summer rises all the way to that selfsame 68.) 

Also, with so many hotel guests frequenting the pools all summer long, they pool water has to be backwashed frequently. Backwashing is the process of cleaning a swimming-pool's filter by reversing the flow of water. Rather than flowing into the pool, it flows out, flushing  contaminants. This eliminates the necessity of cleaning the filter manually and it's another way of running out the water heated up by the ambient temperature and replacing it with the cool water from the tap. Then, of course, the water has to be heated up again. 

That's why Vegas pools are heated to between 73 and 78 degrees in the summer. 

Some people (older, as a rule) might find that a bit chilly even in the height of the heat, though kids don't notice at all and anyone swimming or active in other ways acclimate quickly. Lap swimmers, for example, prefer water in the 75- to 80-degree range.