Houston Winter Weather Statistics

[Ptarmigan]

Here is a list of Houston icestorms going back to 1960.

http://www.wxresearch.com/almanac/houice.htm

If we use statistics based on the data, ice storms should occur on average, every 2.09 years or 2 years.

Formula
1 / (23 / 48) = 2.09

Also, here is a table of below 16 degrees in Houston going back to 1892. 1895 and 1899 were quite cold.

http://www.wxresearch.com/almanac/freeze.htm

If we use statistics based on the data, 16 degrees and below days should occur on average, every 4.46 years or 4 to 5 years.

Formula
1 / (26 / 116) = 4.46

Now, if we want to know how often Houston will see 10 degrees or less, which is single digits, it should occur on average, every 29 years.

Formula
1 / (4 / 116) = 29

As pointed out, natures does not care for statistics, however, we can use it as a way to predict.