> ground-based detectors like LIGO measure the higher frequencies, pulsar timing arrays measure the lower frequencies, and space-borne detectors like eLISA measure stuff in the middle.

Does this data correlate with weather events, earthquakes or cosmic rays?

Weather events and earthquakes - no.

Cosmic rays - Astrophysical events that generate gravitational waves can also generate electromagnetic and particle emissions. If a black hole crashes into a neutron star, all kinds of stuff is going to come out.