Perth has been sweltering in its hottest summer in 33 years and second hottest summer in more than 110 years of records, according to weatherzone.com.au.

“It’s virtually a certainty with the rest of the month staying well above 20 degrees at night and rising to the mid 30s every day,” weatherzone meteorologist Brett Dutschke said.

The summer maximum will average at just under 32 degrees, about two degrees hotter than the long-term norm and the highest in 33 years.

The summer average minimum will turn out to be 19 degrees, one and a half degrees warmer than the long-term norm and the highest in 19 years.

Combining nighttime minimums and daytime maximums, the average temperature will come out at 25.4 degrees, the highest since the summer of 1977/1978 and second highest on record.

In summer 1977/1978, the average was 26.1 degrees, the highest since records began in 1897.

“The last half of February is the clincher – we’ll end up having 15 consecutive nights warmer than 20 degrees and nearly every day in the mid 30s, record-breaking stuff,” Dutschke said.

The previous longest run of nights warmer than 20 degrees is 13, in February/March 1990, so by Sunday morning a new record will have been broken.

All up, there will have been 60 days of 30 degrees or hotter, about 20 days more than the summer average.

“Two main reasons for the long hot summer; the persistence of easterly winds, bringing heat from the interior and the ineffectiveness of sea breezes, blowing off relatively warm waters,” Dutschke said.

Easterlies were strong and gusty at times earlier this month, fuelling bushfires in the hills.

“There were a few reasons why it shouldn’t have been a hot summer – it was a slow start, it took us 12 days to reach 30 degrees, the longest it’s taken in six years. It also only reached 40 degrees twice, nothing unusual there,” Dutschke said

“Looking ahead to autumn, temperatures should stay near-or-above average due to relatively warm waters off the west coast. These warmer than normal waters should also help rainfall trend back to near average.”

– Weatherzone