weather: local daily temperature histograms?

Weather Underground offers climate data for sites all over the country/world. Example, here’s seasonal data for Madison, Wisconsin. The first plot shows daily average high/low temps throughout the year, along with extremes.

Question: is there some place where I can find histograms of daily high/low temperatures that would give some measure of how variable the local climate is? For example, I’ve spent many Christmases in Denver, Colorado, and I’ve observed daytime highs on Christmas day that were anywhere from 10F to 70F. I don’t remember anywhere near that much variation in Minneapolis on the same day. And I imagine there are other places where the daytime high (or low) for a given day of the year was even more consistent year after year.

So…is data like that available somewhere?

I’m sure there are better sources, but I would look at wikipedia’s climate data for the location and examine the difference between the average high and average lows in that location - here’s Madison, Wisconsin’s.

I saw this post but couldn’t help, historical weather data just isn’t usually available for a certain day going back for years. But if you have an Android device, I just ran across an Android app called Weather History Explorer which does it (although not a histogram).

It’s not very intuitive, but it works. You click on the globe to look up a location, then tap the date to change the date, then tap “Statistic since 19-whenever” and it will display the data for that date for many years like in the third screenshot.

NOAA has this information, and it is free and publicly available.

Years ago, I contacted someone there and they gave me 100 years worth of daily high/low readings for a particular weather station, which I downloaded via FTP.

Here’s their website:

You may need to contact them to get the data you need.

NOAA’s climate normals data for 1981-2010 includes the standard deviation of high and low daily temperatures. I don’t know if you’ve studied statistics, but basically the higher the standard deviation, the higher the variation. About 68% of days should have temperature within one standard deviation of the mean, for example. Unfortunately I am not aware as NOAA putting out anything so nice and readable as a histogram, and the data is hard for a human being to read.

First you have to know the station code. You can consult a list like this one to find that the code for Denver-Stapleton is USW00023062. Next you consult this table of the standard deviation in the daily high temperatures. Use ctrl-f to find the first instance of USW00023062, which is the start of the data for Denver-Stapleton. The “01” stands for January, and the numbers after that (133C 133C 133C 132C etc) stand for ten times the standard deviations of the daily high temperature in degrees Fahrenheit for Jan 1, Jan 2, Jan 3, Jan 4, etc. In other words, the standard deviation in the normal daily high for Jan. 1 at Denver-Stapleton is 13.3 degrees Fahrenheit. Don’t be fooled by the “C”. It doesn’t mean Celcius or Centigrade, but “complete”, meaning that there is no missing data for that date. If there’s an S, R, P, or Q instead of C that means there is less than 30 years of data for that date. To find the data for Dec. 25, go down to where is says “USW00023062 12” (for Denver-Stapleton December) and across to the 25th entry after that to find the standard deviation is 13.4 degrees Fahrenheit. If daily high temperatures are normally distributed (i.e., fit a symmetrical bell curve), you would expect a Christmas day 26.8 degrees warmer than average (2 standard deviations) about once every 50 years and one Christmas day 26.8 degrees colder than average in the same time period.

Now you can compare that to the Minneapolis-St. Paul Airport (station code = USW00014922) and find that the standard deviation there is 12.2 degrees Fahrenheit. So there is less variation in temperature on Christmas day in Minneapolis than Denver but not by a huge amount. They are quite similar to each other compared to the radically lower standard deviation in San Francisco, which is only 4.2 degrees.

NOAA has many other datasets than standard deviation in the daily high temperature. See this page for a list but to make any sense out of the abbreviated file names, you need to consult this readme doc.

What I stumbled upon by chance is a Spanish website, with pages like March 1999 stats for Minneapolis. I suppose they get their data from the NOAA site others mention. The data for different months and stations are found with predictable URL’s. I don’t know how many stations are provided altogether, but they have six just for Minneapolis.

Extracting specific statistics from the data is just a “small matter of programming”. :cool: I’ve done this myself with sed/awk scripts. It might be nifty to put up a Javascript page to do this automatically, if there isn’t such a thing already.

(Using Tutiempo.Net would be a silly detour if the NOAA data is nicely formatted. I’ve found many U.S. government websites to use stupid, even proprietary, formats, but a scientists’ site like NOAA is probably an exception to that gripe.)