Charlie Parker's bar, in the basement at Fred's, Paddinton, Sydney. Photo / Supplied

If you catch Sydney on the right day, it feels like a fine Auckland summer. Clear skies, crisp mornings, then a perfect high of 22 degrees, with a gentle breeze across the harbour. When the sun is high, you'll find yourself peeling off a layer and ordering something on ice.

But if the weather is cooler, the city has much more to offer than sunshine, beaches, and harbour views from rooftop bars. There's a quieter, moodier side to the city, that makes Sydney ideal for chilly days, and dark and stormy nights.

For old-school charm, you can't beat The Grounds of the City, a beautiful cafe in the heart of Sydney. With its dark woods, low lights, parquet floors and banquette seating, this "dawn till dusk" bistro feels straight out of Shoreditch or the Left Bank, and serves gorgeous food to a noisy and energetic breakfast crowd, and then the noisy lunch and cocktail crowds that follow.

At the breakfast seating, over strains of jazz, I order a salad loaded with roasted vegetables, crispy chickpeas, labneh with sumac, sauteed spinach, grilled halloumi and topped with a perfectly poached egg. A warm, healthy yet still indulgent breakfast of champions.

I didn't expect to find one of my favourite ever meals in a tin. But at the Continental Deli, a charming neighbourhood spot in Sydney's inner west Newtown suburb, the future is canned. Cocktails, Mediterranean sardines and even souvenir T-shirts sit in fanciful tins on the shelves, while behind the bar, under racks of dried garlic and bottles of spirits, staff mix, serve and charm.

This small eat-in deli promises cold cuts, cheese, canned goods and stiff drinks, and it delivers on all of them – my sardines come served in their tin with fresh chopped herbs, accompanied by plain crackers, and a swipe of sea salt-topped butter across the plate. There are pickles and a rye sourdough to graze on, and several cocktails were sampled – the "Mar-tinny", and the "Can-hattan".

There are heartier mains to choose from – on the day I visited, steak tartare, octopus in Galician sauce, and a charred eggplant and white bean dish were all on offer. But the sardines, preserved in France in their beautifully bright retro cans, proved impossible to resist.

There are two Continentals to choose from – in the CBD (where a more extensive menu is offered) and the original in Newtown, which also has junk shops and some of Sydney's oldest terraced houses to peruse after your meal and cocktails.

When the weather is really coming down, what better way to escape than to disappear underground, to the warmth and comfort of the cave-like QT Spa?

QT hotels are known for their modern bold design – bright colours, dynamic room layouts and bespoke staff uniforms by local designers.

In Sydney, the QT is housed in two historic central buildings – the State Theatre, and the Gowings Building, both completed in 1929. The gothic entrance to the hotel was once the entrance to a grand Art Deco shopping centre – to your right, original full length gilded display cabinets still house mannequins modelling clothing, and to the left, the ornate old lifts, ready to transport you away to your spa experience.

Walk past the ground level Gowings Bar, and take the lift downstairs, where the showy eccentricity of the QT's signature style tones down, and enter a warm, quiet basement of neutral colours and soft fluffy robes.

The spa is housed in an old barbershop beneath the hotel – the tiles on the walls are original, as is the Vitrolite ceiling. In the room to where I am led for a massage, there is the remains of a tiled step that customers once rested their feet on, and an old mirror plastered into what remains of the original tiles.

Later, I pop back to the bar. Gowings is an intimate space, perfect for escaping the weather. On the street side, the old shopfronts are now windows on to the world of commuters and consumers rushing by outside. Further in, an L-shaped bar, original mosaic floors, and tables for two are dotted around, filled with an easy business lunch crowd and a cheeky early afternoon cocktail drinkers. The interior is dark, warmly lit, and filled with original features of the former department store. I take a stool at the bar, order an espresso martini, and drink in a truly unique slice of Sydney's history.

If you prefer your spas airy and light-filled, down at Darling Harbour you'll find the Crown Spa, an exclusive spot on level 6 of Crown Towers, right on the harbour.

This picture-perfect spa is much more than just the service you book. In the building's lobby, stewards will usher you into the correct lift and send you up through the levels to your destination. Be sure to get there early to take advantage of the "aqua retreat" - a series of saunas, steam rooms, showers and the beautiful spa pool – access is A$85, or free for guests booked in for an hour's treatment (as is valet parking).

Each room of the spa itself is impeccable – from the soft mauve and aqua tones, to the gentle curves of the tiled walls, and the view across Sydney. Numbers are strictly limited here, so book well ahead to ensure you get the time you'd like.

I tried a Subtle Energies body wrap treatment, an hour that was so delicious, I could not stop saying "thank you" afterwards. I was scrubbed with a gorgeous earthy blend of crushed walnut shells and cloves that left me baby soft, then slathered with clay infused with spirulina and green tea, and wrapped in soft white sheets. After rinsing off, the final step was a no-nonsense massage of my scalp, shoulders and feet – before being ushered into a private relaxation room, where I drink tea, enjoy snacks, and gaze into the middle distance until I can pull myself away.

crownhotels.com.au/sydney/crown-spa

What could be more warming than a pot of tea for two, wrapped in a hand-crocheted tea cosy? I'd say enjoying that tea with scones, cakes and club sandwiches. Down at Sydney's historic The Rocks, The Tea Cosy is tucked away in a heritage building – one of the seven in Playfair Terrace, a two-storey Victorian terrace built in 1880. Inside, you'll find bookshelves packed with old records (and players – you're welcome to put on an LP of Hello Dolly or The King & I), old china, books and embroidery. Outside, there are chairs and tables, bunting and tea cosies aplenty.

On the menu you'll find finger sandwiches, homemade jams, cheese and sweet scones, and a range of teas from traditional black to herbals – plus the occasional hot tea toddy with spiced rum. I try curried egg, and salmon and dill sandwiches, then scones with blood plum and rhubarb jam. Along with an Australian Billy tea (a smokey little number), the experience is truly cosy. So grab a Devonshire tea, pour yourself a cuppa, and embrace your inner granny.

On Oxford St, Paddington, Fred's is a cool inner-restaurant and farm kitchen mixed up in one. The kitchen is in the dining room, (or is the dining room in the kitchen?), creating an atmosphere that is much like gathering around a friend's kitchen as they cook for you. There are huge worktops and bowls piled high with fresh ingredients within arms' reach for the cooks. There are bunches of herbs and lemons to grab, and a team of chefs work so close and openly, you can watch your meal being put together. There are natural linen tablecloths, and an open fire, where meat and vegetables go to grill and roast and char. And all this is wrapped up in the beautiful parcel of heritage building, sympathetically restored to feel old and loved.

The menu is all fire and heat – from the candles burning in old-fashioned chambersticks on the tables to the blistered skin of the Murray River cod. Start with a spritz, something light and refreshing to sip as you choose what you'll eat. Don't be shy about ordering many courses – the menu is designed to enable it. As the night closes in, I try tuna tartare, that blistered cod, a simple green salad and then marjolaine for dessert – a gorgeous slice layered with meringue, buttercream and nuts. To accompany – some heady Aussie red to warm the belly, as you watch the cooks prepare your next dish. merivale.com/venues/freds

Next stop, simply slip downstairs to Charlie Parker's, a speakeasy-style bar hidden beneath the street. Far from being a dingy basement spot, Charlie Parker's has dark woods, warm red carpets and seating, moody lighting and exposed rafters that house vermouths infused with botanicals on-site, and jars of honey that have been collected from hives kept on the roof (they're not sure where the bees go to collect their pollen, but the resulting honey is tasted and cocktails are created to pair with those flavours).

This is a perfect date spot for couples who are not after candlelight and quiet. Instead, the dates here are getting stuck into cocktails (named for the part of the plant they are derived from - the menu includes "nut and fruit", "root and soil", and "leaf and flower"), while Chuck Berry booms from the speaker. I try a martini made with kiwi-infused vermouth and an oyster on the side. It puts a serious flush in my cheeks, just enough to brace me for the drop in temperatures outside.

For more things to see and do in NSW, go to sydney.com