iphone in a humid country

On a quick search, I found 5 stores that sell Apple products in Cyprus. Based on the fact that Apple products are available, I don't think they would be sold if there was a problem with the weather. I think you should be fine.

See this from an internet search: Relative humidity of the air is on average between 60% and 80% in winter and between 40% and 60% in summer with even lower values over inland areas around midday. Fog is infrequent and visibility is generally very good. Sunshine is abundant during the whole year and particularly from April to September when the average duration of bright sunshine exceeds 11 hours per day. It does not get that humid. Where I live we have had some days with over 90% humidity and I have not had any problems with my phone.

I would not worry about it. IPhones are routinely used in very humid environments, equal to or more humid than any on Cyprus. Even just here in the USA, places like Louisiana or Florida or my own North Carolina will see summer days of 90-100+F heat and air so drippingly humid it almost looks denser than normal. You step outside and your clothes are instantly damp. Yet my iPhone 7 (and previously 6, 5, 4 and 3GS) works just fine in it.

I had my iPhone when I lived Southern Louisiana and it was fine.