A hot air mass which is sweeping through Western Australia, South Australia and Victoria will not exclude western parts of Sydney later this week. Penrith is set for a spell of hot and sunny weather with the mercury not likely to fall below 30 degrees each day until next Sunday. From mid week, a four day run of 35-degree plus days is likely, with some places potentially nudging 40 degrees before the cool change arrives in around a weeks time. Typically Penrith receives at least two days which reach 40 degrees or more at this time of year, and on average there are seven days in January which are greater than 35 degrees. The last time Penrith, Richmond and Camden saw four consecutive days of temperatures above 35 degrees in January was in 2010. Although it may be one for the record books if there is four consecutive days greater than 37 degrees at Penrith. For those seeking relief from the relentless hot days, along the coast will be much cooler. The city and surrounds will remain in the high 20's most days under persistent sea-breezes.