For only the fifth time in the last 20 years Perth has put together four consecutive 38-degree days. The temperature today eventually hit 40 degrees at about midday, its hottest day since New Years Eve when it reached 42.1. With Perth almost certain to reach 38 degrees tomorrow this will be the first time in 27 years that it has achieved five 38-degree days in a row. The last time the city had more than five 38-degree days in a row was 48 years ago, when there were six days, which is the record. The record of six days is unlikely to be eclipsed. A low pressure trough which has been just off the west coast since Saturday will move inland. This will bring an end to the sunny days and northeasterly winds which have been supplying the heat. The trough moving inland will allow cooler sea breezes to develop more readily and bring a bit more cloud. This will be a relief for people who struggle to cop with the heat. After a noticeably cooler day on Thursday it will heat up again on Friday and Saturday before it cools even more. Friday and Saturday will not get nearly as hot as in the last few days, only reaching the mid 30s.