The warmest indoor swimming pools in Canberra are the 20 metre lap pools at Aquatots in Forde and Gold Creek. Both of these pools are kept at a cosy 33 degrees Celsius. They are at an elevated temperature because they are mostly used for kids swimming lessons. Public swimming is available every day of the week at Forde, but only for one hour to three hour windows. It is a good idea to check the pool's website for these details before you go. For casual swimming times at Gold Creek you will need to ring them up, as they are not currently listed on the Aquatots website. It is a condition of entry that you need to wear a swimming cap in these pools.
Warm water lap swimming can be a great way to get moving on cold days
If you are looking for a 25 metre lap pool, the warmest available is at Club Blue (part of the Canberra International Sports and Aquatic Centre) in Bruce. The temperature of this pool is 32 degrees. It also has a 50 metre indoor lap pool, but it is several degrees cooler than the 25 metre pool.
Interestingly, despite its crisp winter climate, Canberra does not appear to have any dedicated public hydrotherapy pools (typically 34 degrees or above), apart from one at the Australian Institute of Sport, which is not available to the general public.