[Data Viz] Have you ever seen the rain?

Make it rain on these homes! 

We found this Microsoft Power Map Visualization of 30 years of annual precipitation visualized geographically. Here’s the breakdown from the MSPowerMap Imgur account:

Please check out the video tour of this data it’s worth it: http://youtu.be/DGgZArdluKU Ever wonder just how much more precipitation there is on the West Coast vs the East Coast? Wonder no more. We have visualized cumulative precipitation data including rain, snow, sleet, and hail from 1981-2010 showing just how much of a difference there is. Data is for the United States from http://prism.oregonstate.edu/normals. Visualization was built using Microsoft Power Map for Excel. Have questions? Here’s a gallery with alternate views on the data: http://imgur.com/a/4PsEU For more follow us: http://www.facebook.com/MSPowerMap and http://www.twitter.com/MSPowerMap

It’s a very interesting visualization- note how consistent precipitation is on the east coast of the country versus the massive fluctuation on the west coast. Since we have this as a reference, let’s look quickly at how Wazers’ reports of precipitation line up.

We took the aggregate number of all reports regarding rain, hail and snow per US city since January 2014, and compared it to the total number of alerts (Traffic, construction, accidents etc) and then chose the top 20 cities based on the percentage:

US top 20 precipitation percentage

In the above graph, we color-coded the top 20 according to region of the United States, starting with the darkest shade of blue on the west coast and moving to lighter shades as you move East. The one exception is Hawaii, which is a neon blue.

Regional Precipation US

We then looked at, on average, the percentage of Precipitation alerts in each US region and ordered it on the graph from West to East. Doesn’t look too much like actual country map, does it?

Why the difference?

The data Microsoft used is cumulative data over 30 years of precipitation. We clearly do not have 30 years of precipitation report data, though honestly even if we did, this would probably look the same. We’ve already observed that severe weather impacts driving significantly in a separate post, therefore it’s not assured that every time it snows, sleets, or rains that someone on Waze reports it.

The vast majority of people in the US drive Monday through Friday, from the hours of 6AM – 9AM and 3PM – 7PM. As a result, on average the United states receives 51% more alerts on weekdays than weekends, and 34% more weather alerts.  And that’s not even taking into account how much rain occurs outside of normal working hours.

There’s also the aspect of geography- in the West much of the precipitation happens at high elevations, especially in the winter months. Though some people commute to the top of a mountain for work, it’s definitely not a consensus.

In comparing the three graphs, we find the most interesting part to be the list of cities with the highest percentage of weather reports. That’s likely due to the lack of other alerts, like traffic or accidents. Most rural, less densely populated areas do not endure the insane level of traffic in cities like Los Angeles and New York City. On the other hand, New York and Los Angeles do not suffer through the extreme weather of the northern Midwest, like North Dakota or Iowa.

In closing, there are a few points that we believe explain the discrepancies:

  • People in areas with less traffic notice weather more
  • People are more likely to report on Weekdays, when they’re driving to and from work
  • When weather happens outside of normal working hours, Wazers are substantially less likely to report it
  • Precipitation can, and will occur in areas sparsely populated areas

If precipitation falls in a forest, and there’s no one around to report it, does it happen? Of course, but Wazers could care less.


Amazing cover image Copyright 2015 Gregory Thielker. Check out his work here: http://www.gregorythielker.com/