As in, the historical "Opens" based on the daily OHLC charts. I've noticed CME, HQuotes, Barchart.com and most historical providers give an open price that often isn't anywhere near what my chart software shows at 9:30. .. and if anyone knows of a site that might provide 9:30 open prices, let me know
That's because 9:30 isn't the "open" of the ES session. Since the ES trades almost 24 hours a day, the "open" is based on the open of the actual ES trading session, which is at 4:45pm ET of the previous day (i.e., the "Friday" session runs from Thursday @ 4:45pm through Friday @ 4:15pm) - it's not the start of regular trading hours at 9:30am. Unless there's a website that does it for free, if all you're looking for the OHLC from 9:30am to 4:15pm only, you'll probably have to use a datafeed-based charting program and have it produce 415 minute price bars for regular trading hours only.
Wait... ever heard of timezone? Did you know that NYSE and NASDAQ is located in NY... Did you know that CBOT and CME is located in Chicago???
I use Qcharts and had the same question. I noticed the daily chart reflected a different open than the hourly hart by a lot so I asked them. They said for them the daily open occured at 9 am, but if not using 24hr data, which I don't, the open is at 9:30. Makes sense to me, I don't use 24 hr, so I am good to go.