I noticed that some of the products you use contains glycerin. Glycerin pulls the moisture from the air. You mentioned living in a dry climate. This may be the problem.

I am a glycerin user in the Spring and summer because I live in an area where the dew points are great for glycerin during those times of the year.

Also, use warm water when co-washing and rinsing your hair. This helps to open the hair cuticles and allow moisture to get in. If you DC, use a plastic conditioning cap for a few minutes to open the cuticles and allow some moisture to enter.

BC 11/23/2008
Low porosity, Fine/Medium Texture, S-Curls

Co-wash: VO5 Tea Therapy
Rinse Out: Garnier Sleek 'n Shine (subject to change)
Styler: Long Aid Curl Activator

Dislikes: Proteins (except occasional Silk protein), Cones, Oils