How the season changes the route you should design

The same town wants a different route in July than in January. Not a shorter one necessarily, but a differently shaped one: different side of the street, different order, different bail-out. Designing seasonally is the cheapest improvement available to anyone who already knows how to draw a route.

What to take away

• Summer routes follow shade. Winter routes follow sun. That single rule reorders most days.
• Daylight, not temperature, sets the winter distance budget.
• Storm season means the bail-out has to be a building, not a bus stop.
• Air quality standards are averaged over set periods, so a forecast is not a snapshot.

Summer: design around shade

In summer the usable side of a street changes through the day, and a route that ignores it is significantly harder than the same distance in spring. Plan the outbound leg on the shaded side and accept a longer crossing to stay there.

Two other summer adjustments. Move the climb to before nine in the morning, and put the green stretch in the early afternoon rather than saving it for the end.

Winter: design around daylight

Winter walking is limited by light, not cold. In much of the northern United States you have five or six usable hours, which means a five-mile route with two indoor stops rather than a nine-mile loop.

Reverse the summer rule: pick the sunlit side, and route so that the return leg faces away from the low afternoon sun rather than into it. In a town with any grade, put the descent at the end as well, because cold legs and an icy slope are a worse combination than tired legs and a climb.

Winter also rewards a route with more doors on it. Passing four places you could step into for ten minutes is worth more than passing one large attraction, because the day is built around short recoveries rather than a single long stop.

Season	Route shape	Bail-out should be
Summer	Shaded loop, early climb	A cooled indoor space
Autumn	Longest routes of the year	A bus stop is fine
Winter	Short loop, two indoor anchors	A building that is open
Spring	Flexible, rain-dependent	Somewhere with a roof

Read the air forecast properly

Air quality figures are averages over defined periods rather than instantaneous readings. EPA's NAAQS table sets out the national standards for the six criteria pollutants along with their averaging times: ozone on an eight-hour basis, carbon monoxide on both eight-hour and one-hour bases, nitrogen dioxide with a one-hour and an annual standard. Primary standards are set to protect public health, including sensitive groups such as people with asthma, children and older adults.

For route design that means an eight-hour ozone figure describes a whole afternoon, not a moment. If the day is forecast poorly, shortening the walk by an hour does less than moving it to the morning.

Storm season changes the bail-out

Where and when severe weather is likely, the bail-out point has to be somewhere you can wait indoors. EPA's page on smart growth strategies for disaster resilience and recovery covers how communities plan for and recover from hazards, and towns that have done that work often have identifiable public buildings that stay open.

Find one before you set out, and put it on the map. A bus stop is not shelter.

Our guide to how walking itineraries are built covers the underlying structure, and the season guide for downtowns covers which months are best to visit in the first place.

Common questions

Is autumn really the best walking season? In most of the country, yes. Stable weather, long enough days, and low humidity.

How short should a winter route be? Five miles with two indoor stops, finishing before the light goes rather than after.

Does rain need a different route or a different day? A different route. Rain is a surface and shelter problem, not a cancelation.

What about spring mud on unpaved sections? Reroute onto paved streets. Spring is the worst season for anything unsurfaced.