This Federal Aviation Administration (FAA) and National

as well as several private research groups and universities. The primary goal of MWISP was to improve prediction/detection of potential aircraft icing by gathering data from remote and in situ sensors. The MWISP team did not experience the conditions they had hoped for during the month. Having expected a greater frequency of icing in deep clouds, NCAR commissioned Plymouth State College (PSC) to develop a detailed climatology for Mount Washington for the month to determine if April 1999 was anomalous compared to the long-term April climatology (Markle et. al, 2001). When the month was determined to be anomalous, the FAA supported PSC’s effort to expand the initial climatology to encompass all months of the year. This paper reports on a portion of the results from this expanded study. These data can help determine the best potential icing times for similar, future experiments in the Mt. Washington region