How To Use CLIMOD 2

By Paul Homewood


 As you know, I have been using CLIMOD 2 a lot lately. It is a very powerful analytical tool for working with official NOAA temperature and rainfall data.

It takes a bit of getting used to, but is easy once you get the hang. So, as promised, here’s the idiot’s guide!!





CLIMOD is part of the Applied Climate Information System, which is operated by NOAA’s Regional Climate Centres. You can though access data from any part of the US via any RCC – I always use the Northeast, simply because I came across it first.

You can also, apparently access global data, though I’m not sure how up to date any of it is.

Anyway, on to Lesson 1!


If you open the above link, you will see the selection screen – all three boxes need selections.


Product selection offers a variety of reports, and it is best to play around to see what is best in any one situation.

I find Daily Data for a Month useful, as this gives data for the current month (although some stations only update monthly).

The main report I have been using recently however is Seasonal Ranking, which takes you onto this screen for Options Selection:



As you can see, you can select graphs, tables and CSV. You can also pick seasonal or monthly output, and a date range.

The variable drop down box offers Max temp, Min temp, rainfall etc. I have selected Max temp, which then offers the following choices under Summary.

1) Maximum – this gives the highest temperature each year (for whatever month/season you pick)

2) Minimum – the opposite!

3) Mean – this shows the average daily maximum temperature each year, again for the month selected

4) Number of days – this will chart how many days were over a certain temperature (which the system will prompt you to enter.) In the same fashion, you can do the same with rainfall.

5) Percent of days- the same as 4), but as a percentage.

You can choose the number of missing days you want to allow – in the above example, if there is no data for more than five days for a particular month/year, the graph will return a blank field, so I find it better to increase the number, to avoid too many gaps.


And then we get to the fiddly bit – Station Selection.

Type in the location where the image sign is:


I have entered Sacramento, but there are several stations in the surrounding area you can choose from – see drop down box labelled “Station”.

This is a little bit of trial and error, unless you know which specific station you want. Many sites only have a few years of record, but if you click GO, you will soon see which ones are which.


The selection I have made above gives this graph. It is interactive, so by clicking on the graph line, you can get the value for that year:





There is also a table below – by clicking on column headers, you can sort by column.



This box  image allows you to download .

Remember that these are all sourced from official NOAA daily data. NOAA make massive adjustments to monthly figures, via various homogenisation techniques. The daily data however tells the truth.


September 22, 2020 at 04:03PM

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