This Papua New Guinea is nearly tropical and we get rain in almost all seasons. But over the past few decades, it was observed that climate is changing considerably. Changes in solar influx, frequent volcanic eruptions and greenhouse gas emissions aggravate this effect. In this scenario, climate variability in Papua New Guinea has been studied using atmospheric parameters like atmospheric temperature and rainfall published by Bureau of Meteorology, Australia for the period 1996-2018. In order to improve the forecast of climate variability, the data has been analyzed using wavelet methods. An increasing trend of atmospheric temperature and rainfall are observed with a yearly periodicity except 2007-2009. The night-time atmospheric temperature showed quasi-periodic variations of two-to-four years. These variations will be discussed in terms of the SOI variations, volcanic eruptions and increase in greenhouse gas emissions.