Carnarvon, about 800km north of Perth has just had its hottest week on record and is unlikely to cool down significantly until later this week. The Gascoyne coastal town averaged a maximum of 42.1 degrees in the week to last Saturday, 10 degrees above the long-term norm for this time of year. Its previous hottest week in 66 years of records was in 1988 when the average maximum was a touch under 42.1 degrees. Last week's heat peaked on Friday with a top of 44.9 degrees. A weak cooler change moved through on Saturday with little effect. The coolest day in the last week and a half was Sunday but it still got to 36.7 degrees, five above average. After this cooler change, forty-degree heat is now returning. At 10:30am this morning it had reached 41.5 degrees before a sea breeze dropped the temperature by seven degrees in less than 30 minutes. Today is the seventh time it has reached 40 degrees in the last 11 days. Typically in a summer there are four or five forty-degree days. Apart from cooling sea breezes most days there is not much relief. There's a fair chance of hitting 40 degrees again tomorrow and Wednesday before a low pressure trough forms inland. This developing trough will allow sea breezes to develop earlier in the day again and for maximum temperatures to fall short of 40 degrees. Residents will have to wait until next week for temperatures to stay below the mid 30s for longer than 24 hours as cooler winds will filter in from the south.