Christchurch has experienced a dramatic temperature shift, with scorching heat followed by a rapid cool change, as forecasters warned more hot and windy conditions were ahead for the weekend.

Meteorologist Thapi Makgabutlane said the city reached a high of 31.7 degrees before a fast moving front moved through with a southwesterly change.

She said temperatures dropped by about 9 degrees in less than 30 minutes.

“We went from just under 32 degrees all the way down to 22 degrees very quickly,” Makgabutlane said.

Despite the sudden cool change, hot conditions were set to return on Saturday. Makgabutlane said Christchurch was expected to reach around 31 degrees, with overnight temperatures only dropping to about 20 degrees.

She said the lack of overnight relief prompted the issuing of a heat alert to give residents advance warning.

“It is going to be a hot day and there is not much relief overnight,” she said.

Sunday was expected to be similar, or slightly warmer, with temperatures forecast to reach about 32 degrees.

Strong northwesterly winds were also forecast to continue through the weekend. Makgabutlane said a strong wind watch was in place for Christchurch, while inland Canterbury was under a strong wind warning, with gusts potentially reaching 130 kilometres per hour.

She said the combination of high temperatures and strong winds increased the fire risk.

“For people heading out this weekend, checking its.nz will be a good resource,” Makgabutlane said.

Residents were urged to stay up to date with the latest forecasts as conditions continued to change.