Elevation-adjusted temperature

Standard weather forecasts read the temperature at a low-elevation grid point, not at the trail. For a high-altitude trail, that gap can be 1,000m or more. Without correction, you get the valley temperature instead of the trail temperature.

Every trail in MudWatch has a real GPS track with elevation. We compute the trail's actual altitude from those coordinates and lapse-rate-correct the displayed temperature, the apparent ("feels like") temperature, and the soil temperature. The conditions panel shows "(adjusted for trail altitude)" whenever the correction is meaningful. The cold-and-hot rules in the recommendation engine fire on the corrected number, so alpine trails get accurate frost warnings even when the valley is shirt-sleeve weather.

When will the trail dry out?

Knowing the trail is wet now is half the question. The other half: when will it be back in prime condition?

MudWatch reads soil moisture forward through a 7-day window and combines it with evapotranspiration (the rate the soil loses moisture to sun, wind, and dry air) to predict when conditions will recover. If today is too wet, the conditions panel shows you when the next dry window opens. If the soil never drops back to a rideable level inside the forecast horizon, you'll see "stays wet through forecast window" instead of getting your hopes up.

Trail-specific drying

The atmospheric forecast tells half the story. The trail's own terrain tells the other half. MudWatch analyses each trail's GPS polyline to compute its dominant aspect (which compass direction the slopes face) and its average steepness, then biases the drying prediction accordingly:

• North-facing trails in the northern hemisphere stay shaded longer and dry slower. We extend the recovery window for trails whose slopes predominantly face north or north-east. (Mirrored for the southern hemisphere.)
• South-facing trails get more direct sun and dry faster. We pull recovery in for trails with strong south-facing exposure.
• Steep terrain sheds water quickly. Steep trails recover faster than the local average; low-angle, flat trails hold puddles in low spots and dry slower.

The bias surfaces in the trail's recommendations as an extra line beneath the dry-by prediction, e.g. "Slopes face north; expect drying to lag the forecast by 12-24h on shaded sections".

How wet is the trail, really?

The grip curve is a hump, not a slope

A bone-dry trail is dusty hardpack: corners blow out, dust over the surface eats grip. A waterlogged trail is mud: tyres pump, lines wash out, riders erode the trail. The sweet spot is tacky. Moist enough to bind, not so wet that it pumps. The score is shaped to match that physical reality, not "more rain equals worse."

Surface-aware grip curves

The grip curve shifts per surface type. Rock and pavement barely care about moisture. Roots get genuinely dangerous when wet. Clay turns gluey from the first sign of damp. Sand prefers slightly moist over bone-dry.

So a "wet rocky descent" and a "wet rooty descent" get scored very differently, even though the underlying soil moisture reading is the same.

Two-layer soil moisture

Most apps glance at recent rain. MudWatch reads the soil at two depths and uses whichever is wetter during your likely riding window. The shallow layer responds in minutes. The deeper layer takes days. Reading both lets us tell the difference between "rain just stopped, surface is slick" and "soaked through to the bones".

The best window today, not just "today is fine"

"8/10 today" doesn't help you plan. MudWatch scores the next 12 hours individually, weighing soil state, rain timing, temperature comfort, and the daylight budget for a trail of this length. The recommendation comes back as a specific time: "around 09:00".

In tropical climates, that's early morning or late afternoon. Midday gets pushed down by heat. In northern winter, it's mid-day. The cold ends of the day get penalised instead. Same model, opposite advice, no climate switch needed.

Sunset-aware. A window that wouldn't leave enough daylight to safely finish the ride gets hard-cut. Lost-light-on-the-mountain is a real risk we don't pretend otherwise.

Conditions that matter, surfaced when they matter

Every trail is a real GPS track

The mini-map on a trail page is the trail's actual shape. The elevation profile is its actual climb and descent. Length, max altitude, start and end heights are all derived from the GPS, not from metadata that might be wrong. Hover the elevation chart and a synchronised dot moves on both, with distance and altitude at that point.

The trail's bearing falls out of the same data and powers the sun-glare and headwind features. Without a real GPS track, none of those would exist.