There's a site that will graph crude oil plus gasoline prices for up to three selected cities, very nicely done.

http://www.grandrapidsgasprices.com/retail_price_chart.aspx

What's interesting to me is the comment I've heard that gasoline prices usually lag crude oil prices by about 6 weeks, which would be consistent with the notion that it takes time for crude to be refined into various products and distributed nationwide to gas stations.

Well, play with the graphs on this site. No matter what options I select, there is no appearance of lag time at all. What's up? Any thoughts?