Gasoline prices climbed on Wednesday, marking their highest level on record for this time of year. The national average for regular gas stood at $4.03 per gallon, according to AAA data. Gasoline prices were in their second stretch above $4 per gallon this year, after dipping periodically below that level in June and July. Read more: Find the best credit cards for buying gasAn impasse between the US and Iran over shipments through the Strait of Hormuz has kept oil prices volatile. Click here for in-depth analysis of the latest stock market news and events moving stock pricesRead the latest financial and business news from Yahoo Finance