Sections

Why sections

A single forecast for a whole drive would average away exactly what matters: the one stretch of freezing drizzle between two hours of clear road. So the road is divided into sections, each with its own forecast, its own arrival time and its own rating.

How the road is divided

The app reads the forecast along the whole route — a point about every five kilometres, each for the moment you will be there — and then groups neighbouring stretches that read alike: the same kind of weather, the same rating, and a similar temperature, with freezing as a line of its own.

• Sections follow the weather, not the odometer. Hundreds of kilometres of the same clear weather can be one section.
• A hazard keeps its own section. A short stretch worse than the road on either side is never merged away, however short it is.
• A long drive has up to about thirty sections. The app aims for sections at least a thirtieth of the drive long, within limits, so a short drive has a few and a long one has more. A drive in uniform weather has fewer.

Each section is described by the part of it that matters: its forecast, place name and arrival time come from the middle of its worst weather, not from its midpoint.

How they are numbered

Sections are numbered in the order you drive them, from 01. The numbers are the same on the map, on the strip at the top of the timeline and in the timeline’s rows, so a number is enough to find a section in any view.

Forecast for when you get there

Every section is forecast for your departure time plus the driving time to reach it. The first section of a drive leaving now is a forecast for the next few minutes; the last section of a five-hour drive is a five-hour-ahead forecast. That is why the later sections are the ones most likely to change before you get there.

Open a section

Tap a section in the timeline, or its marker on the map, to open it. The sheet shows:

• the condition, such as “Light rain”, with the place and the temperature;
• its rating, with a sentence on what it means for the drive;
• ARRIVING, DISTANCE and LIGHT — the local time you get there, how far it is from the start, and whether it is light or dark;
• CONDITIONS — eight readings: feels like, wind, gusting, chance of precipitation, precipitation, visibility, humidity and cloud cover. A reading that crosses a threshold on its own carries a small mark of its own;
• Show on map, to see where it is.

IPHONE & IPAD

ANDROID

Tap any cell to open its LEARN sheet, which explains the reading in a few lines. Each LEARN sheet has a page here, under Conditions, Severity, Daylight and Local and elapsed time.

Sections and the briefing’s stretches

The briefing groups the road differently: it speaks in stretches of similar weather along the drive, built from a coarser division of the route. Its stretches do not always match the timeline’s numbered sections one for one. The briefing explains.