You've gotten good advice. I'll just note that the mealworms will do better as humidities approach 70% but that as you get higher than that, you set up conditions that are good for catastrophes. Grain mites and fungi and bacteria that attack insects become more active, sporulate or otherwise reproduce better at higher humidities. It's not that your colony will be attacked by such threats, but that the risk is much higher. It's a bummer to loose most or all of your colony so I always recommend growing under conditions that reduce such risks. The benefits to increased mealworm growth with increased humidity are not great enough to counterbalance the increased risk, at least to me. My humidity measures less than 20% for most of the year and my colonies do just fine. Temperature is different, while risks also increase somewhat as temperatures increase (not as much as humidity), the benefits to growth rate are great enough to easily outweigh those risks. I put my colonies on the back patio during the summer to take advantage of the heat. As hannakat recommended, why not try both environments? You do increase your risk as you increase both heat and humidity, but the conditions you're describing are at the lower end of the danger zone. Just go into it with a watchful eye to any changes in the colony and take care to change conditions if things start going south.
