Welcome ~
If your potting mix is chunky and gritty ...and if water flows out almost as fast as it gets added ...you're fine
if not try this mix .....
Adenium Soil Mix – Mix together:
1 Part: Coconut Coir -
1 Part: Redwood Bark (or) Orchid / Phalaenopsis Mix - Break-up, cut or crush larger stems & bark
1 Part: Poultry Grit (or) Pea Gravel
1 Part: Perlite - coarse -
1 Part: Sand - coarse = Leveling, Horticultural, Builder's Sand > screen out fine sand & dust
1 Part: Lump charcoal - Break-up, Crush to 1/4" to ½" sized pieces > screen out dust
1 Part: Lava-rock – (volcanic cinders or pumice)
In a re-potting mix pinch?
You can safely substitute a half and half mixture of "Big Box Store" Orchid / Phalaenopsis Soil Mix + Cactus / Palm Mix
Leave your adeniums outside .....I am getting the same rains as you ... as long as each plant has sufficient drainage - and - no plant is sitting in water ...you will be okay
Also ...once rain becomes a little less frequent - give plants a good 7 days after a rainfall - before turning on the hose