We're still swimming (near San Francisco), but with gas assist to heat the pool. With some rainy and cloudy days, plus cooler days and nights, the pool temperature drops quickly. With the opaque safety cover, the pool loses 3-4 degrees Fahrenheit overnight and if there's no sun during the day it loses another 2 or so during the day. The sun is much lower in the sky so the solar heat isn't as fast. If we didn't have gas heat, the pool would probably be below 80F now, but still probably above 75F due to some sun.

Since my wife uses the pool for swim exercise therapy, she'll probably use it until the first week or two in November. Then she'll switch to an indoor pool at a community center which is far less convenient. Heating our pool with gas to 88F ain't cheap. Without accounting for heat losses, it costs around $2.33 per degree Fahrenheit (with gas costing $1.39 per Therm).

Richard