Rain measurements from the iRON network are taken by a tipping bucket rain gage, which means that measurements during the winter when temperatures are below freezing may not be accurate. Measurements for Smuggler Mountain's rain gage are not available from August 2013 through May 2014.
Soil moisture responds differently to rain events based on size of the event. This means that the amount of water available to plants will vary depending not just on the amount of rain that falls in the course of a month or a week but also on whether that amount falls a little at a time over a long time or all at once.
There is also a global connection: between the rain seen in local weather patterns and patterns of temperature and wind seen around the planet. Climate models suggest that in the future frequency and intensity of rain events may change. Since moderate rain events have a different impact on soil moisture than heavy rain events, a change in precipitation patterns may have an impact on soil moisture levels and curves even if yearly precipitation does not alter alter significantly, and will certainly have an impact on soil moisture if yearly precipitation does alter.