For information on Sno-Park fees and permits:
The most popular route starts at the road just north of I-80 at the Castle Peak/Boreal Ridge exit. The road is paved for an eighth of a mile or so up to the gate where it turns into a dirt road and heads north. There are guidebooks and information out there suggesting starting south of I-80 at the PCT trailhead. The PCT goes under a bridge often flooded with water, and is very hard to follow. It is also way longer. For day-hikes, the road north of I-80 is recommended.The road terminates after about one and a quarter miles. A trail continues north to Castle Pass at 7,938'.
From Castle Pass there are two options. If just hiking Basin Peak, head down the PCT until you reach Round Valley at about 7,850'. You can go straight up to the summit from the valley, or continue up the trail a little further to gain elevation. Generally, this approach has a distance of between 4 miles to 4 1/2 miles one way, gaining about 1,800'.
The second option is to head up towards Castle Peak. Before getting up to the ridge between Basin Peak and Castle Peak, head north towards Basin Peak and descend to the saddle. There are a few ups and downs, and the true saddle is actually about 3/4 miles from Basin Peak. The total distance via this route is a little under 4 miles one way, gaining a little under 1,900'. If combining Basin Peak and Castle Peak, the total round trip distance is about 8 1/4 miles. If combining Basin Peak with Castle Peak, many often do the trifecta, and include Andesite Peak 8,219'. This can be done as a loop, by hiking up Castle Peak first, then Basin Peak, then down to the PCT to Round Valley back to Castle Pass. Then heading up to Andesite Peak, dropping down to the Hold in the Ground Trail and back to the trailhead. I did this on May 24, 2015. It was only about 9 miles total, gaining less than 3,000'.
Typical Sierra winter weather patterns are encountered here and the summers are usually mild to warm.
By virtue of its location and orientation, the Sierra Nevada mountain range is the first area that receives significant precipitation in the form of snow. Many tales of people at odds with extraordinary winter weather originate from the area of Donner Pass including the famous Donner party. Weather data has been gathered here for over 130 years and can be accessed online. Please take a look at weather historian Mark McLaughlins home page:
Considering how much snow this area receives it should come as no surprise that the ridge between Castle and Basin Peak and a portion of the north ridge of Basin Peak usually become corniced in the winter. So, here is a link to the local avalanche report:
Local weather report: