Indoor celebrations are in favour for most of the Northern Territory and parts of Western Australia where showers and thunderstorms are expected, according to senior meteorologist Dean Narramore.

Residents down south are likely to enjoy fine and sunny weather, ideal for barbecues and backyard cricket, he said.

FORECASTS BY STATE/TERRITORY

WA - Perth can expect a hot lead-up to Christmas with temperatures approaching 40C and Christmas in the 30s. Monsoonal conditions will continue further north in the state, he said.

SA - Temperatures in the mid-to-high 20s.

VIC - A "fresh" start to the morning, warming to a comfortable afternoon in the low 20s. The mild weather will continue into the next day for the Boxing Day Test.

TAS - Cooler than all the other states with Hobart "flirting" with 20C and mostly fine.

NSW/ACT - Showers and thunderstorms are expected in eastern parts but "it won't be washout". Residents west of the Great Dividing Range can expect warmth and sun. Sydney and Canberra can expect Christmas in the high 20s. A large high pressure system on the east coast should be good news for the Sydney to Hobart Yacht Race.

QLD - Brisbane can expect Christmas in the mid 20s with showers and possible storms. Thunderstorms in other parts of the state could burden areas with already saturated river systems, making flooding a concern.

NT - Darwin will see typical tropical weather with about 20C and thunderstorms expected. Across the rest of the territory, residents will likely see widespread heavy rainfall and flooding up to Christmas.

Australian Associated Press