Any downside to this?

[Broken]

I have my two 150 ct humi's inside a large cooler that until now has been perfect 70% with my Cigar Oasis and temp between 67-69 degrees. Now that it is getting warmer and I don't run the air conditioning while we aren't home the temp gets 75+ during the day (or it will).

Can I throw an ice pack in the cooler to keep the inside temp down without harming the cigars? I would guess the humidity would drop for a qhile until the CO unit brings it back up, but otherwise is there a risk in this?