A Selected Assemblage of Climate Visualization Products for Washington DC at Varying Scales: Annual Time-Series Plots to "Hour-by-Month Climograms"

Utlizing a variety of data sources, the purpose of the following study is to provide a medley of visualization products that depict the climatological character of the Washington DC area for different time scales of interest - annually down to a combination of monthly and diurnally.

The observational periods of record for Washington DC daily temperature and precipitation observations recently passed milestones in that their continuous uninterrupted recordings now stand at 150 years plus (complete year histories commencing with 1872 for the former and 1871 for the later), and thanks to the NOWDATA NWS online resource, the data are digitized in their entirety, and easily accessible (this also includes 1884-85 to present snowfall data). With such lengthy periods of record available combined with the ongoing backdrop of Climate Change, it is of interest to investigate and describe the overall year-to-year pattern changes over the histories. In these instances, the graphical presentation mode will be year-to-year bar charts.

Not nearly as lengthy in historical availability, but still appreciable in volume, are individual hourly observations, which can be transformed into diurnal and seasonal graphs of means and extremes. In this case, thanks to the Iowa State METAR site, Washington D.C. National Airport hourly observations, in some cases available back to the late 1930's (but continuous from 1973), are readily accessible online as well. These include temperature, dewpoint, relative humidity, wind direction and speed, cloud coverages/heights, and visibilities. To this end, the observations can be downloaded, reduced, and transformed into "Hour-by-Month" Climograms, a type of chart that depicts the diurnal vs. monthly variations of climatological parameters on single page layouts analogous to topographical maps. Some of the paired hourly observations such as temperature and winds or temperature and dewpoint can also be utilized to produce Wind Chill and Heat Index readings, respectively, which in turn can comprise annual year-to-year extremes charts.

These contrasting types of graphs are assembled together as an "exhibit", providing information on both the large-scale (long-term secular) and smaller-scale (diurnal/seasonal) aspects of Washington DC climate.