Regardless of your approach to the Southern Interior , you’ll spend time driving Highway 3, which branches east at Hope  and continues parallel to the United States border all the way to Alberta . If you are winding your way east from Vancouver  to Calgary  (Alberta), you could plan to take at least two days to travel via the Southern Interior, but you will need at least three or four days to see all the highlights.
Along the way, dozens of roads and highways of varying importance branch north through parallel north–south running valleys. The most direct of these is Highway 97 through the Okanagan Valley, which passes the towns of Osoyoos , Penticton , Kelowna , and Vernon . Passing numerous lakes, orchards, and vineyards, it’s a truly spectacular drive.
You could plan to spend at least one day in and around each population center, mixing traditional sights such as the Desert Centre at Osoyoos  with Okanagan wineries  and swimming at Kalamalka Lake .
Like the Okanagan Valley, planning your time in the Kootenay region is more about your own interests than seeing specific sights. There is historic significance to the main population center of Nelson  and the ghost town of Sandon , but you’ll also want to allow time for exploring the parks and indulging in water sports.
From Nelson, Highway 3 continues its eastward course to the next and easternmost of the Southern Interior’s major valleys. The main attractions here are historic parks such as Fort Steele Heritage Town  and soothing highlights like Fairmont Hot Springs . Forming the eastern boundary of the Southern Interior are two national parks, Kootenay  and Yoho , which are geographically aligned with the famous parks of Alberta, but are within British Columbia .
If you’ve taken three or four days to get this far from Vancouver , plan on another one here, walking around Emerald Lake  and taking the gondola at Kicking Horse Mountain Resort . Two of the most special places in the Southern Interior, both within Yoho National Park, require advance planning. Lake O’Hara  is only accessible by shuttle bus, while the Burgess Shale  can only be visited with a guide.
For many locals, the warm lakes and mountain parks of the Southern Interior are a destinations in themselves, and therefore July through August are by far the busiest months of year. This is when temperatures are at their hottest and the waterways at their busiest. If you’re planning to camp, reserve a spot as far in advance as possible. As a general rule, the summer weather will be hot, especially in the Okanagan Valley and along the border, with temperatures cooling off as you climb into the surrounding mountains.
The winter resorts of the Southern Interior are not as well known as Whistler  and their counterparts in the Canadian Rockies , but between them they offer something for everyone, from the family atmosphere of Silver Star Mountain Resort  to the facilities of Big White  to the untracked powder of Red Mountain . If you do decide to visit during the cooler months, you’ll find the major attractions open but with shorter hours. Many Okanagan wineries close completely during winter.
One other useful note when planning your time in the Southern Interior : Roads are generally narrow and winding, with mountain passes and ferry crossings slowing down travel time considerably (there are no less than six mountain passes between Hope  in the west and Cranbrook  in the east).