The SendScore estimates how good climbing conditions are at a crag — one number from 0 to 100%, built from weather data and rock physics models with the crag's own characteristics.
We track the sun's position to determine the irradiance at the wall, and evaluate whether it feels comfortable. Too intense on warm days or missing on cold days, both are penalized.
Judged on the feels-like temperature at the wall — sun, wind, and humidity folded in. The score drops as it leaves the comfort window (too hot or too cold), which sits cooler for bouldering than sport climbing.
Judged on the effective wind that actually reaches the wall (see Rock Physics Models below). A light breeze is ideal — it dries holds and skin. Strong wind and heavy gusts are penalized.
This is the "silent killer" of friction. If the rock temperature is colder than the dew point of the air, moisture will condense on the rock surface, making it wet even without rain.
Current rain is the biggest score killer. We also consider the probability of precipitation: even if it isn't currently raining, a high forecast risk lowers the score to reflect uncertainty.
This factor comes from our moisture model. Shaped by the crag's characteristics, it reflects how recent weather conditions drive moisture absorption and evaporation throughout the rock material over time.
Low humidity is almost always better for friction. High humidity reduces the score, making the rock feel greasy. The muggy feel of humid air on warm days counts through the feels-like temperature.
The score favors daylight hours. It ramps up at sunrise and ramps down at sunset. Climbing is encouraged to happen during the day.
The SendScore is not just about the weather forecast; it is about how that weather interacts with the specific crag. Following characteristics are taken into account in our models.
We track the sun's position to determine when each wall is sunlit or shaded. A wall's aspect shapes sun comfort and how warm and dry the rock gets, so the score is computed separately for each orientation.
The steepness matters. An overhang or roof receives less rain than a slab or vertical wall, meaning it might stay dry during light rain.
Different rocks absorb water differently. Sandstone might act like a sponge (taking longer to dry), while granite might shed water quickly.
Trees shelter the wall from sun and wind. That shade keeps it cooler, but the blocked sun and wind also mean it dries more slowly after rain.
For each wall orientation we model what the wall — and the climber on it — actually experiences.
The forecast wind is not what the wall feels. We derive the effective wind at the wall dependent on wind direction versus wall orientation, gustiness and the vegetation cover. It drives the wind factor, the wind chill, and the drying of the rock.
Our rock physics models determine the temperature actually felt at the crag: air temperature, plus the sun on your skin, plus muggy air on warm days, minus the chill of the effective wind. Computed per wall orientation and judged by the Temperature factor.
We simulate the thermal mass of the rock. It heats up in the sun and is cooled by wind, by the surrounding air and ground, and radiation to a clear sky at night. This is crucial for predicting humidity condensation on the rock surface.
We track how much moisture the rock holds — soaked up from rain, or even condensed straight from humid air — shaped by the rocktype and how sheltered the wall is. Wind, sun, and dry air then dry it out, letting us estimate how long the rock stays wet.
Often yes. North- versus south-facing, steepness, rock type, and tree cover all change how the same weather plays out — so even nearby crags can legitimately score very differently. It can also happen the other way around: if one crag is missing some of its characteristics, two places that are actually similar may still score differently (see Limitations).
Each wall aspect is scored separately: a sunny south face and a shaded north face on the same crag genuinely differ in sun, warmth, and drying. Use the wall-orientation selector on the crag page to switch between them.
Large crags can span several sectors with different aspects and surroundings, but a single entry carries only one set of characteristics — so the same vegetation, inclination, and rock type apply to all of it. The wall-orientation selector lets you pick the most relevant aspect, which covers the biggest difference. Storing each sector as its own entry with its own characteristics would be more accurate; we are steadily improving the database toward that, but a lot of manual work remains.
The rock holds moisture and dries only gradually. The model tracks that drying, so a crag stays penalised until it has actually dried out — not the moment the rain stops.
Other factors can hold it back: humidity, condensation risk, wind, temperature, or a high forecast rain probability. The "Why this score?" breakdown on each crag page shows exactly which factor is limiting it.
It's an estimate built from weather forecasts and modelled rock behaviour, not live sensors — so treat it as guidance, not certainty. See the Limitations below for the specifics.
No. A high score reflects friction and sending potential, not safety, and never replaces your own on-site judgment. See the Disclaimer below.
The SendScore is calculated for the entire crag and neglects route-specific features. Our models are not aware of seeping holes, tufas, bird droppings, bee nests, dirt from rare visits, loose rock, or other unforeseen condition killers on specific routes.
The score relies on weather forecasts which can be inaccurate. Furthermore, rock drying speeds and temperature retention are approximations based on general rock types, not real-time sensor data.
Accuracy depends on the correctness of crag data (orientation, rock type, altitude) in our database. Where crucial parameters are unknown, we use defaults which may lead to incorrect scores.
Climbing is an inherently dangerous activity. Always assess the risk and conditions of a climb yourself before starting. Do not climb outside if you lack the experience to judge safety and conditions independently.
A high SendScore indicates good potential for friction and sending conditions, not safety. Never attempt a climb you are not prepared for just because the score is high.
The SendScore is a tool intended to help experienced climbers identify the best potential climbing days. It does not replace common sense or on-site judgement.
Always respect local crag access regulations, potential bird bans, and parking rules. Inform yourself before visiting a crag.
The creators of SendScore assume no liability for accidents, injuries, or wasted trips resulting from reliance on this data.
Color Palette
Logo
UI Display Settings
Make daily/hourly scores bold in lists and charts
Show colored suitability bars under weather cards
Show sunrise and sunset times on the Sun Exposure card
Smoothly blend suitability colors instead of using blocks
Show colored glow around the main SendScore card
Show orientation selector inside the SendScore card instead of above it
Show colored SendScore timeline suitability bar inside the sticky top header
