During some summers when produce shipments are in peak volume, so much 
product needs to be moved, and the demand for refrigerated equipment is so great, that already high rates then go through roof. It certainly has not happened this summer, and if anything, produce rates declined leading up to the Fourth of July holiday. The Fourth, being on a Wednesday, is felt by some to lessening the impact on rates.
Rates from major some shipping areas, for example in California, dropped 5 to 10 percent and more from the San Joaquin Valley, Salinas Valley, and Santa Maria.
A number of factors apparently resulted in the lower, although still healthy produce rates. For example, stone fruit shipments out of the San Joaquin Valley are down this year, freeing up some equipment. Other areas are shipping a lot less produce than normal such as Michigan (with fruit) and many Southeastern (watermelons, bluesberries and vegetables) states and in the South (Texas watermelons and melons in loutheastern states).
Still, the heaviest produce volume, on a national basis, usually occurs between May and August – and that still holds true this year.
In California, table grape shipments are winding down in the Coachella Valley, but the big volume is yet to come – from the San Joaquin Valley. Grapes have started from the Arvin (Bakersfield) district….The Salinas Valley remains heavy with vegetables shipments.
Southeastern Arkansas is in peak loadings with tomatoes.
Kentucky and Tennessee are now shipping tomatoes, zucchi, strawberries and peppers. Most shipments are on a regional basis.
Although we usually don’t think too much about ports and imported produce this time of year, various ports around the U.S. are receiving summer citrus. for example, there are arrivals of navel oranges from Peru. There is various types of citrus arriving from South Africa, Argentina, and Uruguay.
San Joaquin Valley fruit and vegetables – grossing about $7,500 to New York City.
South Texas watermelons – $3000 to Chicago.