Canberra's latest string of frosty mornings has hit a new benchmark for extreme overnight temperatures.

Since early Monday morning Canberrans have spent more hours in temperatures below zero than above.

Overnight, Canberrans shivered through a low of -7 degrees, with mercury only climbing above zero after 9:30am.

This follows Monday's cold temperatures which saw 20 centimetres of snow fall on the New South Wales ski resorts and Canberra region, the -7C lows experienced on Tuesday morning- which matched temperatures in the Snowy Mountains, and Wednesday's -5C lows.

A layer of frost blanketed the region on Thursday morning. ( Supplied: Stephanie Horne )

Bureau of Meteorology forecaster Sean Carson said temperature lows seen this week, along with last August's extreme run of lows only occurred once a decade.

"August last year saw a pretty impressive run of overnight lows, where we saw eight consecutives nights below -5C, with the lowest night in that sequence getting all the way down to -8C," he said.

"But prior to that it is probably something we only see every 10 to 15 years where we get such cold minimums."

A tap frozen over in Canberra's -7 degrees overnight temperatures. ( ABC News: Andrew Messenger )

Mr Carson said this "impressive" run of temperatures was more common in the 1970s.

"It used to be fairly regular before the 1970s, before we saw a lot of development across Canberra, which did give Canberra a little bit of heat coming from industry," he said.

Thursday morning's chilly temperatures also extended to the Great Dividing Range.

"It has been very cold again across the region. Tumut was -8C, Goulburn -7C and the Snowy Mountains were also -7C," Mr Carson said.

Shards of ice cling to a spider web in Holt, Canberra. ( Supplied: Stephanie Horne )

Mr Carson said frosty conditions were set to continue with the El Nino taking effect in Australia.

"With the El Nino conditions across the Australian region it tends to lead to dry conditions, clearer skies and I'd say more of these frosty mornings are likely to continue throughout winter," he said.

Temperatures are expected to rise to -1C on Friday morning in Canberra, before it drops back to -5C on Saturday morning.

Minimum temperatures are expected to climb to 1C over the long weekend.