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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Regional Report weather desk. Data from national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
Check the live forecast above before any balloon launch—wind speed and cloud cover determine whether it’s safe to release. Weather balloons are the backbone of atmospheric data used in everyday UK forecasts.
What does a weather balloon measure?
A radiosonde package attached to the balloon captures real-time readings of pressure, temperature, humidity and wind speed as it climbs through the troposphere and stratosphere.
- Data is transmitted back to ground stations and fed into computer models that generate your local forecast
- The Met Office launches balloons from twelve UK sites, including Camborne, Lerwick and Hemsby, typically at 00:00 and 12:00 UTC
- A typical flight lasts 90–120 minutes before the balloon bursts and the package parachutes back to earth
How high do weather balloons go and what size are they?
Before bursting, a latex balloon expands from about 1.5 metres diameter at launch to around 8 metres—roughly the size of a family car—at maximum altitude of 30–35 km.
- Standard weather balloon size starts at 600–1200 grams; larger balloons reach higher but cost more per flight
- Average weather balloon height in the UK is 30 km (100,000 ft), well above jet aircraft cruising levels
- For hobbyists, a weather balloon kit typically includes the balloon, parachute and a GPS tracker—a common entry-level setup for student projects and amateur radio enthusiasts
Where can I buy a weather balloon in the UK?
Specialist suppliers such as Meteoshop and Science Studio sell weather balloons for sale directly to educators and hobbyists. Prices start around £60 for a basic 600 g balloon; a full weather balloon kit with tracker costs £200–400. Amazon lists some options but check seller ratings carefully.
What is the main purpose of a weather balloon?
Its purpose is to sample the atmosphere vertically—measuring temperature, humidity, pressure and wind—at altitudes no tower or aircraft can reach. This data is essential for accurate short-range forecasts, aviation weather and climate monitoring.
Are weather balloons reusable?
The balloon itself bursts and is not recovered. The radiosonde payload often survives the fall and can be returned to the Met Office for refurbishment—around 20% of UK-launched sondes get posted back by members of the public.
Sources
For the latest conditions at launch sites across the country, check the UK weather hub or the 10 day weather forecast to plan your own balloon experiments around settled high-pressure windows.