Used command:
wget --load-cookies ~/.urs_cookies --save-cookies ~/.urs_cookies --keep-session-cookies -r -c -nH -nd -np -A nc4,xml "https://gpm1.gesdisc.eosdis.nasa.gov/data/GPM_L3/GPM_3IMERGDF.03/2015/01/"

Followed instruction from NASA website: https://disc.sci.gsfc.nasa.gov/recipes/?q=recipes/How-to-Download-Data-Files-from-HTTP-Service-with-wget