Just so we know what we are getting ourselves into (weatherwise), I thought it would be interesting to look at monthly average temperatures (always mild), rainfall (almost nonexistent), and relative humidity (high). Here are the data.
This graph shows the variation in temperature. The high on the red line is 27ºC = 87ºF. The low on the blue line is 15ºC = 59ºF, so temperatures really don't vary much in Lima.