Diesel is usually around mid-grade here, at least during parts of the year.
Right now it's a bit more, kind of between mid and premium. Seems like over the last 10 years or so, the spread between grades of gasoline has really widened. I remember when every single station was a uniform 10¢ difference between grades. So if the Raceway sold regular unleaded for $1.299, mid would be $1.399 and premium would be $1.499. Nowadays, 15¢ is the low end and some stations like Shell are 30 or even 49 cents per gallon different. Since they don't post the mid and premium prices on signs anymore, I feel sorry for the folks whose car run on those grades, because they are getting hammered.
The Shell nearest me today at 4 am:
RUG - $2.649
MID - $3.139
PRM - $3.629
Diesel - $2.899 / $2.959 (credit)
Go down the road a mile, and the Circle K is selling premium for $3.129 and diesel is $2.929. As you can see, this makes making a blanket statement comparing higher grade gas and diesel prices here kind of difficult.
Prior to Memorial Day diesel was anywhere from $2.799 to $2.999. Now it's $2.929 to $2.999. The high end is holding tight to the three buck ceiling, but the low end has shrunk.