For broader coverage in both space and time, the US National Oceanic and Atmospheric Administration provides archives of past weather analyses and operational forecast model output that can be requested by the general public. These datasets contain gridded model output with common parameters at various levels through the atmosphere on a national to global scale. While these datasets do not strictly consist of observed measurements, they are useful for analyses extending beyond the relatively limited set of observations available in most circumstances. Output from various operational forecast models is available for near-current or future conditions, whereas the reanalysis datasets provide similar information obtained from model analyses of past weather.

For a given location, the reanalysis datasets can be used to identify climatological temperature, moisture, or wind characteristics for a given location and date or season. Information from radiosondes or model forecasts can then be used to identify how conditions at a near-current (or future) time compare to these "average" conditions.