Hello, I'm new to violin, and I bought an apprentice fiddlerman violin. It was super nice and the sound is awesome <3. it came with a case and a hygrometer. According to everyone online, the instrument must be kept between 40-60 humidity wise. However the case shows a "normal" mark on the hygrometer that goes a little bit high of 40 going all the way up to 78 (this to me, indicates that the instrument should be fine as long as it is not above the normal mark set on the hygrometer).

I live in Mexico city, it is not a dry nor humid area. it all depends on the season. 

Now here's the thing which I'd like you guys to help me figure out.

When I open the case the hygrometer reads 70-75 (when it just has been opened) and then goes down to 59-61 as it adjusts to  room temperature). My house is a bit cold as I live on the ground floor. I though I'd have problems with dryness but the hygrometer shows, when the case is opened, healthy numbers (forgive me, this might sound super ignorant of me. I play piano but I have never EVER played a string instrument before and while I did some research, my knowledge is very basic. feel free to correct me, please!)

Since I never had a violin case, logic indicates me that room temperature must hold when the case is closed. But when I open it, humidity rises bordering dangerously on 80. Then again I don't know if the case that comes with the fiddlerman apprentice violin is actually airtight. Of course I might be drowning in a glass of water, but I do not wish my new violin to grow mold! yikes!

I had the same reading dynamics in Orlando (I traveled there and purchased the instrument). case opened, the numbers were 59-61, when closed for a couple of hours and the case was opened again, numbers rose almost to the limit of the healthy marks (70-75).

I am extremely worried that either the case might be defective OR the Hygrometer, or this is the city's fault and  I have to buy something else to keep humidity levels low (I am a graphic artist and sometimes I use humidity-absorb containers to keep mold at bay from some of my watercolors when they are stored for several months unused -I have several watercolor sets). I did a quick search on google and I see there are little bags that can help me keep the violin INSIDE the case at a reasonable humidity level. But like I said, I might be wrong. 

I'd appreciate some input.