Did some research on LED farming, came across this neat FAQ

LED Grow Lights and FAQs About Lumen and Lux Output of LEDs

between 70 degrees F to 80 degrees F if you wish to accelerate the rate of plant growth
Hopefully that also applies to MJ culture...my new grow cab's current temperature is 23.9 Celsius, which is approximately 75 degrees Fahrenheit which places the new cab temps right in the zone...though I'm getting the feeling I ought to aim for the 80F mark?

Still awaiting delivery of the inline fan...