Okay, So, since I moved here 2 years ago, I have had my tide watch set to "Savannah River" which is about 20 miles south of here. I know that I should have made an adjustment to it, about +20 minutes or so so that the EXACT tide would show, but 20 minutes to me has never been a big deal.

So, per the instructions, I checked the High Tide for Folly Beach today, and it is at 11:59AM. Hilton Head's High Tide is at 12:17PM. So, we are +18 from Folly Beach, so I can program the offset to this....

But, when I moved my tide location from Savannah to Folly, it doesn't match up.

SI says that Folly's high tide is a 11:59AM, but my watch is indicating that the High Tide is at 11:08AM....

Anyone know why that might be? I checked the date and the year and everything is correct.