Solar South Finder Research

A Google search revealed expensive devices and simple solutions.

I started with some background reading on Sun Plotting from Garden Tutor who says, "you need to find your latitude, true south, the sun’s altitude, and its azimuth."  The Tutor goes on to share charts and lessons that are behind a paywall but I found the initial info illuminating. :)

You can get a general idea of true south with some simple math here but rely on your on the ground findings for your specific home-site or greenhouse-site

Sunrise Sunset Calendar is super helpful for getting a general idea of solar noon.  Click on your state, make some selections, and check the box for lat/long.

I looked up University Place, WA (my sister's place), and Goldendale, WA (about 20 miles from my place).

There is an app for that.
NOAA can calculate solar noon, too.
Another Sun Calculator

Calculate Declination to convert from magnetic to true compass reading.

Solar Panel companies like Build It Solar offer information and calculators and this one was particularly helpful with three low-tech ways to locally determine solar south.
Enconn shed more light on the project with four suggestions.  :D

If you have (or choose to subscribe) you can read "How to Find True South for Aligning Solar Collectors" on Scribd.com.

Great info.  Thank you for sharing.

I will add another twist.  One local solar installer said that in our local area (southern Ontario) that our daily cloud patterns are heavier overcast in the afternoon and clearer skies in the morning.  So here, it is better to aim the panels more towards the 10:00 AM sun direction rather than the solar noon.

So if you are in the clear open sky desert and thw sun shines on you all day long, then forget this twist.  Congrats!

Now "ideally", we would have access to multiple years of recorded data showing intensity throughout the day for your specific site to help get the perfect direction; but probably not easily found info.  (Please correct me if NOAA already adjusts from solar noon direction according to local hourly cloud patterns.)  But maybe some discussions/coffees/beers with your local solar installers or local solar farm operators may give some insight to varying from solar noon in your local area.

Have fun and soak up the sun.