in colder climates we lived in, typically when air temps drop below 70 we stop. 65deg on the driveway seems a whole lot colder than 65deg on the lake.
water temps in boise never went above the mid-upper 60's even in late summer. we used wetsuits down to high50's. lower than that we pass.
wetsuits make cold water bearable and as mentioned, typically only the hardcore out in suits so lakes are pretty nice.

now here in vegas, we boated up until mid november with air temps in the 70's and water the same. we had to stop due to layups from the insurance.