I always use yesterday's high / low for short term swing trading decision support.
If we close today under yesterday's low I stay short bias (or start scaling out of underwater swing trades).
If we close inside yesterday's high/low range I hold/stay neutral.
If we close above yesterday's high I am bullish and add to winning swings.
It's simple and I value this approach highly, took me many years and thousands of trades to figure it out
I will back test this for S&P daily since January 2000. I'll do it tonight.
Do you count weekends the same as any other day?
Edit: Your not claiming this method necessarily predicts the next day. You're just saying it predicts near-term. So not sure what to back test.