Personally I think the answer depends on what you want the pool for. While it may be fine for you to jump into and cool off without any pool heat, and once you get swimming around it will be great, but if you have any plans on using the jacuzzi in the evening - or at any time for that matter - it's not nearly as much fun trying to relax in cold water. We have ways had pool heating, regardless of the time of year, because we have found, regardless of the time of year, the water always has an element of cold to it.