Despite the name, the Mars Sea Conditions GPS is a tool for Earth sea buoy data! The app pulls buoy data from the National Buoy Data Center RSS feeds within 50 miles using your GPS location, Beaufort scale translation and matching Beaufort sea-state thumbnails from wikipedia. I have added surf interpretation. If you have a good scale for choppy to smooth surf, let me know.
The app is quite simple and beta (not finished), so any feedback is appreciated. It requires internet and GPS. It only checks your GPS location once so it shouldn't wear out your battery.