I would like to see how big is the correlation between weather and visits to our website, but I can't seem to find any database that has option of downloading chosen datasets. Any ideas?
To be specific I am talking about Poland / Europe.
Wunderground has an API with historical weather (link). You can get 500 free API requests per day, so you have to be patient if you want to go back years. I found for my location a detailed daily history going back to 1997 (high temp, low temp, mean temp, precipitation amount, plus way more).
update: the reason I post this now is that the Wunderground API includes international weather (and not just US).
I did something similar to Chris Gansen for Portland, OR. I downloaded the crime datasets from Portland's open data portal (www.civicapps.org) and the corresponding weather data from NOAA.
I then created a new CSV dataset from the originals where I added fields for temperature mean, percipitation and snowfall, and posted them for other developers to use: