Torres del Paine National Park is in Chilean Patagonia. Specifically, the Province of Ultima Esperanza, which is in the region of Magallanes (Region XII). Punta Arenas, the region's capital, is 312 km from the Park entrance and Puerto Natales, gateway to the Park, is 112 km away. 

By Bus
Buses run direct to Puerto Natales from Puerto Montt, Punta Arenas and, in Argentina, El Calafate, Río Turbio and Río Gallegos. From Puerto Natales buses to the Park entrance take just over two hours. 

By Air
LAN flies regularly to Punta Arenas from Santiago de Chile, Puerto Montt and other Chilean cities. Sky Airlines flies to Puerto Natales. 

By Car
Road access to Torres del Paine and Puerto Natales is via Argentina and the Carretera Austral, one of the most spectacular drives in the world. 

By Ferry
Navimag runs weekly ferries from Puerto Montt to Puerto Natales through the Patagonian Fjords. The journey takes about three days. 

Unpredictable. In summer 100 mph winds are not unusual, and when the wind blows from the Patagonian Ice Cap temperatures can drop 10 degrees Celsius in minutes. On the other hand, hot sunny days are also common. Generally, summer temperatures range from 41F (5C) to 68F (20C) and winter temperatures from 28F (-2C) to 43F (6C). Waterproof, windproof clothing is essential for trekking in Torres del Paine. 

Yes. 

Source: www.pasesparques.cl from where you can buy tickets.

All year, between 8.30 am and 8 pm. 

Most people trek the Torres del Paine W or the Circuit so other trails are usually less crowded. They include Pingo Zapata Circuit, Laguna Verde Circuit and the Paine Lake Circuit. 

Refugios are lodges, which offer basic accommodation to trekkers in shared dormitories as well as meals and usually hot showers. Book them via Las Torres or Vertice Patagonia. Alternatively, join a group Torres del Paine tour with an operater such as BlueGreen Adventures. 

Only at designated camping grounds. Camps Séron, Coiron, El Paso, Las Guardas, Italiano and Britannico are wild, free, campsites. The rest charge from around $8 a pitch. 

You must hike the Circuit in an anti-clockwise direction and this avoids beginning the trek with the most difficult section, the John Gardner Pass, and avoids walking into strong headwinds while you're up there. Hiking the W from West to East leaves the most difficult hike, The Towers, until last, but either direction is allowed. 

It is possible to trek the W and stay in refugios all the way, avoiding camping altogether. Although that means a long day trekking from Paine Grande Mountain Lodge, via the French Valley, to Refugio Los Cuernos (22 km, 13.6 miles, about 8 hours) or, alternatively, doing a return trek to the French Valley from Paine Grande, and then trekking on to Los Cuernos direct the next day. 

To hike the Circuit you will probably need to camp while crossing The Pass. Although it is possible to hike from Los Perros to Refugio Grey in one (very long) day, carrying a tent means you have a backup plan in case of bad weather. 

In theory yes.

Meals are served at the refugios and most have well-stocked but expensive shops selling trekking supplies, such as dried pasta.