The accuracy of hill climb segments on Strava can vary depending on a number of factors, including the quality of GPS signal, the terrain of the hill, and the method used to calculate the segment. Strava uses GPS data from user devices to calculate segments, so the accuracy of the data depends on the quality of the GPS signal at the time of the activity. In areas with poor GPS coverage, such as in canyons or heavily wooded areas, the accuracy of the segment may be lower.

Additionally, the accuracy of hill climb segments can be affected by the terrain of the hill itself. For example, if a hill is very steep or has a lot of switchbacks, the GPS data may not accurately reflect the true distance and elevation gain of the segment.

Finally, the method used to calculate the segment can also impact its accuracy. Strava uses a number of different algorithms to determine the start and end points of a segment, and these algorithms can sometimes produce inaccuracies. For example, if a segment starts or ends near a turn, the algorithm may not accurately capture the start or end of the segment.

Overall, while Strava hill climb segments can be a useful tool for tracking your progress on a particular hill, they should be viewed as estimates rather than precise measurements.

Some of the gradients (eseically maximum gradients) used to calculate some of the segments below ARE somewhat inaccurate and may be unrealistic - either in minor ratios or with spiked gradients due to lack of barometric recording on a device. But they are still a good overall guide, and this is getting better all of the time.