The Bureau of Meteorology’s Sean Carson said the capital would easily reach 37 or 38 degrees.

“Canberra will probably go no higher than 38… our record for December is 39 but I don’t think we’ll get there,” he said.

At 2pm, Canberra had reached 35.8 degrees.

Mr Carson said there was only a very slim chance of storms in the capital on Friday.

“We’ve had storm activity every day for the past three days, about the ranges between us and the coast so there could just be something about this afternoon but the chance of getting something significant in terms of rainfall is very slim indeed,” he said.

"We have a change in wind direction tomorrow as a southerly change moves up the coast bringing some cooler south-easterly winds into Canberra and the temperature falls a little bit back down to 32 degrees."

Mr Carson said Sunday might pass a forecast top of 35, reaching 38 degrees.

Monday's forecast top if 30 degrees with a possible shower, before 28 degrees on Tuesday with mostly sunny conditions.

"A cool change is due Monday night, into Tuesday, bringing temperatures back down to the high 20s and there will be a few showers through Monday night," he said.

"Christmas Day is looking beautiful with a top of about 27 or 28 degrees," Mr Carson said.

Canberra's water consumption has risen to about 213 megalitres in the past 24 hours.

An ACTEW Water spokeswoman said Canberrans should take care with their water use during the hot summer conditions.

"Permanent water conservation measures are currently in place in the ACT and so Canberrans need to be mindful of their consumption to help conserve our valuable resource where we can," she said.

Lawns and plants can be watered using a hand-held hose fitted with a trigger nozzle, a bucket or a watering can at any time but sprinklers and other watering systems may only be used before 9am or after 6pm.

Watering lawns and plants must not result in pooling or runoff, the spokeswoman said.