12 March 2026

Average annual rainfall in the United States


I've been exploring Facebook for about a year now.  There is an abundance of utter crap, including overtly and intentionally misleading posts, but there are also tidbits of blogworthy information.  The embedded image is a screencap and is not clickable. 

Addendum:  A tip of the blogging cap to an anonymous reader who found the source for the mapped data at Raindrop:
"The data utilized in this map is derived from the PRISM available at prism.oregonstate.edu. The PRISM model is known for providing high spatial resolution climate data. This map covers the period from 1991 to 2020 in a 4x4km resolution. To adapt this detailed data for our map, we have processed it to calculate the average annual precipitation across each county. This involves aggregating the high-resolution data from PRISM to obtain an county-wide average."

8 comments:

  1. smittypapMarch 12, 2026 at 4:16 PM

    Thanks. I didn't realize that Guam was a desert island.

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  2. AnonymousMarch 12, 2026 at 6:48 PM

    screen caps work :)

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  3. AnonymousMarch 12, 2026 at 8:44 PM

    Wow, Puerto Rican badlands.

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  4. AnonymousMarch 12, 2026 at 11:20 PM

    https://droughtmonitor.unl.edu/
    ...makes it (I don't go to farcebook any longer) more interesting. you can click through to county level detail and chart for the past quarter century.

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  5. AnonymousMarch 13, 2026 at 6:16 AM

    I think your instincts about Facebook are correct :).
    I lived in Connecticut for many years and this struck me as wrong. I searched multiple resources, and the average rainfall per year is reported between 40 and 50 inches. But nothing close to 60-69 that the map suggests for most of the state.
    Is the source of the map simply "R NEWJ"? Anything more detailed than that?

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    1. MinnesotastanMarch 13, 2026 at 8:17 AM

      I have no idea. What interests me is the pattern, not the numbers.

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  6. AnonymousMarch 13, 2026 at 11:06 AM

    This map, or rather one just like it, can be seen at https://www.raindrop.farm/blog/annual-total-precipitation-averages and comes with the explanation: "The data utilized in this map is derived from the PRISM available at prism.oregonstate.edu. The PRISM model is known for providing high spatial resolution climate data. This map covers the period from 1991 to 2020 in a 4x4km resolution. To adapt this detailed data for our map, we have processed it to calculate the average annual precipitation across each county. This involves aggregating the high-resolution data from PRISM to obtain an county-wide average."

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    Replies
    1. MinnesotastanMarch 13, 2026 at 12:39 PM

      Thank you, anonymous person. I've incorporated the source link into the body of the post. :-)

      Delete