Diesel prices slightly up ahead of potential Harvey disruptions by admin | Aug 29, 2017 The average price of a gallon of on-highway diesel went up nine-tenths of a cent to $2.605 per gallon for the week ending Monday, Aug. 28. This marks the first increase after a short-lived decrease last week. Powered by WPeMatico Share this:Tweet Related Submit a Comment Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Website Notify me of follow-up comments by email. Notify me of new posts by email.