Temperatures in parts of Sydney topped 40 degrees today, as the city sweated through a record streak of 21 days above 26C.

In Penrith, the temperature reached 41.7 by mid-afternoon and hovered just below into the evening.

Closer to the city it wasn’t much cooler with 39.2C recorded at Sydney Olympic Park and 36.9 at the airport.

Blair Trewin of the Bureau of Meteorology told Guardian Australia the scorcher marked the 21st consecutive day of 26C or over in Sydney, a record stretch not matched at any time of year.

The next-longest streak was 19 days of temperatures above 26C in March 2014.

Trewin said the record hot spell was caused by a combination of warmer than normal ocean breezes, few major southerly winds and a lack of easterly troughs that tend to bring rain and cool temperatures. Since the streak started there has been just 9.2mm of rain in Sydney.

Sydney may continue its hot streak, with the bureau predicting temperatures above 26C for at least the next seven days. The coolest days will be on the weekend, with maximums of 27C forecast for both Saturday and Sunday.

Canberra is also feeling the heat with a maximum of 37C while Darwin and Brisbane are expecting maximums of 33C.

Trewin said: “It has been an unusually hot February in parts of the northern tropics because it’s been much drier than usual for this time of year – it’s normally the peak of the wet season.”

The tropics were unlikely to set any records this month, though, as the hottest time of the year is usually in November/December before the wet season starts properly, he said.