Clear plastic container (looks to big for saran wrap now...) over the top should allow RH and temp to increase but at the expense of airflow...
Maybe clear plastic container propped up some so there is space for air to travel...just a thought
Edit: Ughh, 'Mericans...
Do I have it muddled up and 70 is your RH and 22 is celsius?
If so, RH is really humid and yes, you'd want to be around 27-28c