Brisbane has just had its coldest week in nearly 20 years, averaging just over 17 degrees, according to weatherzone.com.au. Brisbane's maximum temperature each day since last Wednesday has averaged only 17.5 degrees, five below the July average for the eight-year-old site. In the same period the maximum at Brisbane airport averaged 17.4, making this its coldest week in 18 years. Archerfield airport averaged only 17.2 degrees, its coldest week in 19 years. In July 1989 Archerfield had a week when the maximum temperature averaged only 16.5. Archerfield's coldest week in 75 years of records was in July 1939, when the average was 16.4. The past week started off cloudy and became very wet for a few days before a dry and cold southwesterly change moved through. Daytime temperatures will rise above average during the week as warmer air gets drawn across the interior in westerly winds.