U.S. gasoline prices have surged to their highest level this year, continuing their relentless climb. National average gas prices in the United States have inched up to $3.873 per gallon from $3.564 a month ago, while a gallon of diesel now averages $4.338 from $3.851 a month ago. In California and Washington, prices have surged above $5 a gallon. Strong demand and a series of refinery outages are largely to blame for the recent rise, while tightening markets have also been pushing crude prices up. Delta's 185,000-barrel-per-day refinery in Trainer…
