Tens of thousands will flock to the streets across the heart of Sydney tomorrow night to celebrate the 48th annual Gay and Lesbian Mardi Gras

Partygoers from across the nation will rush to the city to watch more than 9000 marchers and 170 floats take to the street in the iconic parade.

With festivities that have been running from February 13 until March 1, this edition of the festival follows the theme "Ecstatica".

"Ecstatica is about euphoria as resistance, a reminder that our collective queer joy is on a break from the battle," Mardi Gras interim chief executive Jesse Matheson told 9news.com.au at the launch in November last year.

The theme blends the festival's foundations in protest and visibility with unashamed joy.

So what can people expect heading into tomorrow night?

Parade locations, tickets and parties

The main procession will kick off at 7.30pm tomorrow, sweeping down Oxford Street, Flinders Street, and Anzac Parade, passing through the celebrated Taylor Square "Glitter Club" viewing area, with the parade expected to wrap up at 10.30pm.

While the event is free and unticketed for spectators, some tickets can be bought to secure extra benefits such as prime viewing of the parade and a reservation at a party spot for the night.

Celebrations are expected to go well into the night after the parade.

The state government has extended business hours for shops, bars, clubs, restaurants, breweries and live music venues in Sydney, Darlinghurst, Surry Hills, Potts Point, Paddington, Camperdown, Newtown and Erskineville until midnight this weekend.

The Sunday Laneway party is set to wrap up the marathon of festivities, with music acts starting at 2pm and running until 1am, transforming the Beresford and Hill Street into a street celebration to close out the parade.

What will the weather be like?

Unfortunately, weather conditions this weekend are not looking great, however, that will not deter revellers.

Showers are expected in the early morning, before clearing up by the early afternoon.

Wet weather is expected to return at about 8pm, shortly after the start of the parade, and the damp conditions are expected to persist all night and into the following morning.

Luckily, conditions will clear up at 5pm on Sunday, not long after the start of the street party on Hill Street. 

Road closures and public transport

Major roads across Sydney's CBD extending to Moore Park will be shut from 4pm on Saturday and will not reopen until 2am on Sunday.

Motorists are being urged to avoid unnecessary travel to the city and instead utilise the metro and train services that are set to run for 24 hours.

This is the first time the iconic festival has had around-the-clock metro and rail services running to get partygoers home safely.

NSW Transport is advising people to take advantage of the rare opportunity.

"Leave the car at home," Transport for NSW Coordinator-General Howard Collins said.

"Check signs carefully because your vehicle will be towed."

Light rail services will also run for 24 hours on the L1 Dulwich Hill, L2 Randwick and L3 Kingsford lines.

Light rails will arrive every 15 to 20 minutes until normal services resume on Sunday morning.

On Sunday, bus routes 370 and 343 will also run around-the-clock with added hourly services.

About 300 extra bus services are also set to run to the city from Inner West, Eastern Suburbs and North Shore suburbs throughout the afternoon, along with NightRide bus services.

Standard ticketing still applies, however, with commuters being reminded to tap on and off when using public transport this weekend.

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