I can tell you that your humidity is not 80% with a screen lid, idc if your in Miami, FL. It's winter.
Run to walmart, go to the paint section. Then go an isle over and you will find a accurite hygrometer. This is the most accurite thing that is not ridiculously expensive.
BTW 70's humidity is not bad
speaking of walmart while you're there pick up a accurite thermometer, the brand accurite. it also has a hydrometer built in which is quite accurate. this is only $12 and also comes with a probe for temp.