The 2020 PGA Championship does indeed head out west once more. Other than Sahalee Country Club (Sammamish, Washington) in 1998, the only 2 west coast courses to host the PGA in the stroke play era were Riviera Country Club and Pebble Beach Golf Links, with the last one of those being in 1995. Considering the PGA at Pebble Beach was held last in 1977, it's been over 40 years since the Wanamaker Trophy has been hoisted in the winds and mist of the Pacific Ocean.
TPC Harding Park (commonly known as just Harding Park), is also one of the few municipal courses to host a PGA Championship. There have been several public courses, but only a few such as Tanglewood in North Carolina (Trevino won here in 1974) and Belmont (Snead won here in 1949) in Virginia are true munis. So this gives the Harding Park regulars a chance to see the world's best players attack the course they play so often.
The play at the Masters in 2020 will give us much more information on who's playing well and who are the top favorites, but a quick look at Harding Park and how it may play will help us narrow down the field somewhat.
The course underwent renovations in advance of the 2005 WGC-American Express Championship that it hosted, bringing the max yardage up to almost 7,200 yards. Tiger Woods defeated John Daly in a playoff after they tied at -10 for the championship. It appears from all preliminary information that the course will play almost as it did in 2005, with a par of 70, and holes 9 & 12 playing as par 4s.
Unless San Francisco experiences some unseasonable heat wave, it's likely the temperatures will be in the 50s and 60s, which will add an element of weather into the mix. And if the winds kick up off Lake Merced or the Pacific to the west, or San Francisco Bay to the east, it could easily send scores higher and higher.