What is the nightly noises (deep rumbling sounds like thunder) near San Marcos, Ca?

Question

Is there a military base nearby? What are they testing?

Answer 1

Camp Pendleton is quite close, they could be shelling there or offshore at San Clemente Island.

Answer 2

probably the jets at Miramar (see link)

Answer 3

Well the current forecast for San Marcos, CA is

Tonight: Patchy fog after 11pm. Otherwise, increasing clouds, with a low around 62. West wind around 5 mph becoming calm.

Wednesday: Patchy fog before 11am. Otherwise, partly sunny, then gradually becoming sunny, with a high near 87. Calm wind becoming west between 5 and 10 mph.

Wednesday Night: Patchy fog after 11pm. Otherwise, mostly clear, with a low around 62. West wind between 5 and 10 mph becoming calm.

Thursday: Patchy fog before 11am. Otherwise, sunny, with a high near 89. Calm wind becoming west between 5 and 10 mph.

Thursday Night: Patchy fog after 11pm. Otherwise, mostly clear, with a low around 60. West wind between 5 and 10 mph becoming calm.

So the only thing I can think of is that it could be could be Night Construction using explosives or it could possibly be a fireworks show.

There is also a military base nearby that could be doing night manuvers using artilery.