Sandia Labs has defined solar variability zones by modeling solar variability across the country using a combination of ground measured and satellite derived solar irradiance measurements. The zones represent the magnitude of high-frequency (sub-minute) solar variability—changes in available sunlight—at each location. Photovoltaic (PV) installations in locations with higher solar variability can, all else being equal, lead to larger voltage fluctuations on electric distribution grids than PV installations in areas of low solar variability. Thus, to understand and study the impact of PV installations in a specific location to distribution grid operations, it is important to know the solar variability at that location. To facilitate such studies, solar variability samples from each zone are available.