First frost, and what it does to a display.

What the regional averages say.

Published climate normals put the average first freeze for southeastern Pennsylvania somewhere between mid-October and early November.

Within that range, the pattern is the ordinary one for a city and its suburbs. Built-up ground holds heat, so central Philadelphia typically runs later than the outer townships. Higher, more open ground, such as the upper reaches of Bucks and northern Chester, typically runs earlier. Low-lying spots cool faster on a clear, still night than the ridge above them, so two houses a mile apart can disagree.

If you want a date for your own township.

The regional range is as close as we get. For something nearer your own street, your county extension office and the National Weather Service both keep climate normals station by station, each one taken from a real gauge.

What frost does to a pumpkin.

A whole pumpkin with sound skin comes through a light frost fine. The skin is the defense, and our pumpkins go out whole for that reason. A carved one has a far shorter life outdoors.

Freezing and thawing does the damage. Each cycle softens the flesh a little further, and the softening shows up first where moisture already sits: at the base, on the flat where the pumpkin meets stone or concrete, and at any bruise or cut in the skin.

One thing helps. Keep the base out of standing water and off wet leaf litter, and the freeze has less to work with.

What it means for when you decorate.

Very little. Our porch delivery windows run from mid-September through late October, and the first freeze usually arrives at the end of that range or after it. A display is generally past Halloween before frost is a factor at all.

If you want the display at its best deep into November, a later delivery window buys you that, at the cost of the weeks you give up in September.