The SendScore is a calculated metric (0-100%) designed to estimate the quality of a crag's climbing conditions based on weather data and specific crag characteristics.
It is calculated based on several factors. The score is not merely a snapshot of the current weather; it also incorporates dynamic models that consider past conditions, such as the drying process of wet rock after periods of 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.
Low humidity is almost always better for friction. High relative humidity reduces the score, making the air feel muggy and the rock feel greasy.
The score favors daylight hours. It ramps up at sunrise and ramps down at sunset. Climbing is encouraged to happen during the day.
We calculate an ideal wind based on the temperature. When it is cold, you want still air. When it is hot, a breeze is welcome to cool you down and dry the rock. However, extreme wind gusts are always penalized.
Similar to wind, the ideal sun exposure depends on the temperature. In winter, being in the sun is great. In summer, you want the shade. We calculate the effective irradiance hitting the wall to see if it matches the current temperature needs.
This factor comes from our dynamic moisture model. It tracks how wet the rock is deep down, not just on the surface. It accounts for rain soaking in and slowly drying out over time based on wind and sun.
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.
Bouldering generally prefers cooler temperatures than Sport climbing, where a wider range of temperatures can be tolerable depending on sun exposure and wind. Scores drop as temperatures deviate from the ideal window for the specific discipline (too hot or too cold).
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 calculate the sun's position (azimuth and elevation) and determine if the wall is in the sun or shade at any given hour. This directly feeds into the effective irradiance calculation.
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 and bushes block the wind and sun, slowing down the drying process, but they also provide shade.
We don't just look at the current hour's weather. We run continuous simulations (state machines) for each crag orientation:
We simulate the thermal mass of the rock. It heats up with sun exposure and is cooled by wind and heat transfer to the air and soil. This is crucial for predicting condensation risk of humidity on the rock surface.
We consider the specific rocktype and its capacity to hold moisture from preceding rain. The drying effect of wind and sun are modeled. This allows us to predict how long the rock remains wet after the rain has stopped.
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.
