Color Vision Deficiencies and Weather Communication: A Universally-Accessible, Proof-of-Concept Color Table for Use in Weather Data Displays

Color is an essential aspect of communication that, when used properly, can be a powerful element in meteorologists’ weather messaging arsenal. Unfortunately, concerns have surfaced about color usage across the weather enterprise (e.g., the overarching consistency of messaging and color vision differences experienced by some people). Since work in the arena of vulnerable populations and weather communication has focused on those with myriad individual differences, our work in color has been centered on implications of color blindness for current weather communication color methodologies. Color blindness or, more accurately, color vision deficiency or difference (CVD), has therefore been our priority in the domain of color-related messaging to date.

Color comprehension is unique to each individual and is difficult to accurately quantify from person to person. An individual cannot simply rate his or her ability to perceive shades of green, for example, on a scale from 1 to 10 and then compare this rating with that of another person; we cannot take photos with our eyes and then say “this is what I see! Now show me what you see.” What each person sees is simply what she or he sees; and it is possible for an individual to not even be aware that he or she processes color differently compared to others. This is not to say that every single person’s color vision fluctuates massively; rather, most people generally experience the same shades and ranges of color, with some people’s experiences differing more widely in a general manner, such that they have pronounced differences and problems with color perception.

CVD is a problem for meteorologists because it directly impedes the end-user’s receipt of critical weather information. Nearly all forms of weather media shared with the public include the use of color to distinguish between pieces of important data, with radar imagery, temperature display maps, and color-coded watch, warning, and advisory (WWA) information among the more obvious forms. Even though color is practically infinite (there being 16,777,215 individual color combinations in the RGB colorspace), most individual entities existing across the electromagnetic spectrum are simply slight variations of their color neighbors. The human visual system cannot discern all of these as perceptually unique from one another, so in practice there are a finite number of colors available for use in any given context. As a result, it is easy to create color tables that are difficult for colorblind individuals to interpret. In particular, due to a lack of perceptual ordering and other issues, problems exist with the popular rainbow color table.

Hence, our aims here, building on work dating to 2015, are (1) to discuss weather communication challenges related to CVD and color usage overall, and (2) to propose new ways forward for work in this area. This will be done via a discussion of the mechanics of color vision, and then by an analysis of the various problems we have discovered. We will present a proof-of-concept color table as a solution to some of these problems, including those that exist with the rainbow color table, alongside data collected from members of the general public and meteorologists, on the usefulness of this new scale concept. General guidelines for the crafting of more widely-accessible data displays – for all people – will be discussed as well.