enter image description here

I am trying to perform an analysis on weather and car collisions data of New York city. I have downloaded weather data from NOAA. But I am not able to understand the data provided in the precipitation column of the weather dataset. It has a numerical value followed by capital letter. Some of these letters are: A,B,C,G,I,H.

Example: 0.03G, 0.08A, 0.0H

Can anyone please help me understand what these letters mean here. I have provided a picture of this column. Also, the name of the column in the dataset is PRCP.

  • 3
    If you can provide a link to the dataset you are looking at, it would be helpful. There are quite a few weather datasets from NOAA. Commented Dec 9, 2015 at 12:56
  • I'm going to agree with Jeanne on that one -- even if you don't know where it came from, the column headings might give us a clue. (and the time row -- is it hourly, daily, etc?).
    – Joe
    Commented Dec 9, 2015 at 15:46
  • 1
    And I should say -- I really hate it when people mix concepts like that in a single field. (I suspect it might be type of precipitation (rain, snow, hail, etc), but that's just a wild guess)
    – Joe
    Commented Dec 9, 2015 at 15:47

1 Answer 1


This seems to be the same data mentioned at http://shallowsky.com/blog/programming/NOAA-weather.html .

In their write up, they also link to NOAA's documentation for the document.

Note that this is what's commonly called an 'ASCII table', in which it is not delimited, but contains a number of fixed-width columns.

As such, the field is not '0.00G' but actually two fields, '0.00' (columns 119 to 123) and 'G' (column 124).

Column 124 is a notation of how the value was measured at the given site:

  • A = 1 report of 6-hour precipitation amount.
  • B = Summation of 2 reports of 6-hour precipitation amount.
  • C = Summation of 3 reports of 6-hour precipitation amount.
  • D = Summation of 4 reports of 6-hour precipitation amount.
  • E = 1 report of 12-hour precipitation amount.
  • F = Summation of 2 reports of 12-hour precipitation amount.
  • G = 1 report of 24-hour precipitation amount.
  • H = Station reported '0' as the amount for the day (eg, from 6-hour reports), but also reported at least one occurrence of precipitation in hourly observations--this could indicate a trace occurred, but should be considered as incomplete data for the day.
  • I = Station did not report any precip data for the day and did not report any occurrences of precipitation in its hourly observations--it's still possible that precip occurred but was not reported.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.