What does "ground truth" refer to in weather observations?

"Ground truth" in weather observations refers to the actual weather conditions as observed directly at the surface. This term emphasizes the significance of obtaining real-time, on-site measurements, rather than relying solely on theoretical models or predictions. In meteorology, ground truthing is vital for validating weather forecasts and models, ensuring that the predictions align with what is happening in the environment.

For instance, while weather models may predict certain conditions, ground truth observations provide the essential verification needed to confirm or adjust these predictions based on observed data such as temperature, humidity, wind speed, and precipitation at the location in question. This real-world observation is foundational for accurate weather reporting and forecasting.