Hello DaddyMac, and thank you for your question.
The National Arbor Day Foundation is a good resource to help you
decide which shade tree would be best for your landscaping project.
And if you join the foundation and/or place an order, you will get
some trees for free!
You can search their online tree guide by tree type (including "shade
trees"), soil type, sun exposure and zone. Filling in more information
not provided in your question (soil type, sun exposure) can help you
narrow the choices, as there are several to choose from in Zone 5.
Regarding the "coolest" shade, a tree with wide leaves and a wide
canopy will provide the most coverage. The Sugar Maple and Red Maple
are good choices for shade and beautiful fall color, as well as
varieties of Oak.
"Tree Planting 101" (Southern Living)
"How to Plant a Tree" (TreeHelp)
best "shade trees" "zone 5"
"when to plant" trees
Best of luck with your tree planting this fall!