Restoring Upper-Air Observations in the Cook Islands

Our International Development and Meteorological Data Services teams are proud to be working alongside the Cook Islands Meteorological Service to reinstate upper air balloon launches in the Cook Islands, marking the first launch in over six years.

This milestone follows the completion of a new purpose-built facility in Rarotonga and represents a significant step in restoring critical observational capability under the wider CIS-Pac5 programme.

CIS-Pac5 supports the development of integrated climate and ocean information services, alongside multi-hazard early warning systems (MHEWS), across the Cook Islands, Niue, Palau, the Marshall Islands, and Tuvalu. Re-establishing upper air observations will strengthen weather forecasting, climate monitoring, and regional data sharing across the Pacific. This achievement underscores the importance of strong, trusted partnerships in building resilient and sustainable meteorological services across the Pacific

So, what are weather balloons used for?

Weather balloons are just one of the many ways we observe the atmosphere to support accurate forecasting. We know the atmosphere is three-dimensional, meaning observations of temperature, wind, humidity and air pressure are needed not only at the Earth’s surface, but also throughout the troposphere - the lowest layer of the atmosphere where nearly all weather occurs. Weather balloons carrying radiosonde instruments are released once or twice daily to collect measurements as they ascend through the atmosphere relaying data back to the Met Office itself.