Well let me be the exception to that rule then… I have to run 36 ft / 40 rear. Due to extended highway runs over 75+mph.
Not all lighter bikes have narrower tires etc. A Vulcan 900 is best example. The custom has a front tire half the width of the Classic Lt though the bike is the same size and weight. Not all tires are created equal either, goes well past just the brand but also the intended use. It depends on the structure of the carcass and the compounds used in the tire.
Like I said before some Manu’s will specify product particular information like Metzelers. Where they give you a starting range and inform you to bump it up to X amount of PSI if a certain speed is expected to be traveled.
I like the thought of 87 degrees being fair weather though… have to keep that in my head as I stare at the snow.
THE absolute best you can do is start with the bikes recommendations…. check with the manufacturer of the tire to see if they have any ideal options listed on their site. IF there are none use your own powers of deduction… just would not got BELOW the bikes original specs.