What is the primary purpose of a weather balloon?

The primary purpose of a weather balloon is to collect data on temperature, humidity, and pressure at altitude. Weather balloons are equipped with instruments that gather valuable atmospheric data as they ascend into the atmosphere, typically reaching altitudes of up to 20 miles. This information is crucial for understanding the vertical profile of the atmosphere, which helps meteorologists analyze weather patterns, improve forecasting models, and study atmospheric phenomena.

While surface temperature measurements are important for weather analysis, they are not the primary function of weather balloons. Forecasting the weather over a year involves long-term climatic patterns and models that require different data sources and methods. Lastly, although weather balloons do transport instruments to high altitudes, their primary focus lies in the data collection aspect rather than mere transportation. Thus, choosing the option that highlights the comprehensive role of weather balloons in gathering crucial meteorological data at various altitudes is accurate.