37°C/100°F, hell yeah pretty hot for indoor. I was thinking about outdoor only, sorry to have misunderstood.
You def need a colder intake source, have you thinked about a canadian well ? It's pretty cheap and easy to do for a ganja space. It work very well, even in the most arid sectors of south spain (your garden is like an eden if i compare). The trick is to place a good centrifugal or torin to push the air trough an airsock and you're fine.
plus this (don't deal without)
You don't need to build it like for an house with full equipment. A torin box, an airsock and a D125/4.92 inches (minimum) PVC tube is enough.
Just draw a "snake" like in nokia phone (lol) than finish below the shadow of your closer tree to put just aside the outdoor tube. The more long is the travel, the more regulated will be your intake (winter and summer).
Now yes, it change totally my insight on the strains concerned lol I've known this problematic in a previous lab' and 1KW MH sets, and i just have throwed the pots to replace it with a big bed instead. It help a lot also, pots heat too much in these conditions and it's the main factor of unhappy plants.