  Atmospheric water vapor is the main limiting factor of atmospheric
transparency in the mm and submm wavelength spectral windows. Thus, dry sites
are needed for the installation and successful operation of radio astronomy
observatories exploiting those spectral windows. Temperature and wind are
variables of special consideration when planning the installation and operation
of large-aperture radio telescopes, as these parameters affect the mechanical
response of radio telescopes exposed to the environmental conditions.
Temperature, and in particular temperature gradients, induce thermal
deformation of mechanical structures, while high wind speeds and gusts induce
pointing jitter affecting the tracking accuracy of astronomical sources during
the observations. This work summarizes the statistics of precipitable water
vapor (PWV), temperature, and wind monitored at sites by the coastal mountain
range, as well as on the west slope of the Andes mountain range in the region
of Antofagasta, Chile. This information could prove useful for the planning of
extended baselines for the Atacama Large Millimeter and Submillimeter Array
(ALMA), and/or new radio telescope projects, such as the Atacama Large Aperture
Submm/ mm Telescope (AtLAST) initiative.
