Climate in Paraguay is basically two types in regards temperature - Unbelievably hot (90% of the time) and comfortable (10% of the time).  When it's hot it's also normally very humid. Shorts, sandals and loose clothing is the normal attire to make it thru the hot periods. This winter so far we've had about a month of unseasonably cold weather where it only gets up to around 60 - 70 degree F during the day and down to low 40's F during the evening hours. They even had frost about 3 mornings it was so cold. Otherwise the winter time (June - September) has some very pleasant sunny cool days.  There is also a lot of rain here with the potential for very violent storms with lots of flooding. In Asuncion, as they have very poorly designed drainage for the city, the streets can become raging rivers at times. Plus the rivers can flood and displace whole neighborhoods in Asuncion, which happens annually.  If you come here and either rent a place or even stay in a hotel during the summer, you must insure that there are A/C units that work, otherwise you will be very sorry. Ceiling fans are also required for comfort and most places have them.