Japan Exports of hydrometers, thermometers, pyrometers, barometers, hygrometers to Tonga was US$6.98 Thousand during 2012, according to the United Nations COMTRADE database on international trade. Japan Exports of hydrometers, thermometers, pyrometers, barometers, hygrometers to Tonga - data, historical chart and statistics - was last updated on May of 2024.