Under night conditions, when there is no solar radiation and the sky temperature is low, unglazed solar collectors can radiate heat to the sky thus cooling a storage tank to provide cooling the following day. This study theoretically and experimentally examines the performance of an unglazed solar collector for cooling. It shows that such systems can provide a cooling capacity in the order of 50W/m2 and are able to cool to well below the ambient temperatures experienced during the cooling season. Finally it explores the contribution such a system could make to cooling loads in typical New Zealand and Australian buildings.