Old Weather—part of the Zooniverse network of citizen science projects—seeks to gather and study information from ship's logs as a means of better understanding historical weather patterns worldwide. The goal isn't to prove or disprove global warming but rather to gather information about historical weather variability in an effort to improve the ability to predict weather and climate in the future.

Over the past several centuries, ships have traveled around the world on voyages of exploration and trade, often recording accurate weather observations along the way. (In fact, it was an offense to falsify a log.) Of course, until recently ships' logs were hand written and kept in disparate locations. Logbooks are difficult for a computer to analyze accurately, so the Old Weather project relies on citizen scientists to analyze scanned log pages and input the data appearing on each page.

For example, one of the major areas of interest to Old Weather are log books from the English East India company in the period from the 1780s to the 1830s. About half of the logbooks that exist in the British library for those ships that trade between the UK and India or China have instrumental measurements Old Weather's organizers would like to record.

Old Weather citizen scientists visit the project's home page, log in (see below), choose a ship and get started. Participants are assigned rank based upon the amount of data they input, all the way up to Captain. (It takes 30 weather reports more for promotion to Lieutenant, to give you some idea of how it works.)

Old Weather's organizers cross-check the data that is entered to catch as many errors or inconsistencies as possible.