Weekly cycle of storms

Are storms more likely on Friday or Monday?  An recent article in Geophysical Research Letters (Yang et al., 2016) suggests there is a weekly cycle to thunderstorms over parts of China that is related to the buildup of air pollution during the week that dissipates over the weekend.   Depending on the type of pollution, this can either increase or decrease the number of storms.  So in some areas there are fewer storms on Monday than Friday with the opposite effect in other areas.  There has been similar work in the US (Bell et al., 2008), Moscow and Atlanta. There is also a good review article (Sanchez-Lorenzo et al. 2012)

In Melbourne, Australia, Simmonds and Kaval (1986) found that rainfall increased during the week from a minimum on Sunday to a Maximum on Thursday.  A later study (Simmonds and Keay, 1997) showed that temperatures and rainfall tended to be higher on weekdays compared to weekends.

The Bureau of Meteorology maintains a Severe Storms Archive.  I grabbed the data for Victoria and looked at the frequency of storms on different days of the week.  There are 237 records from 1 Jan 2010 to 11 Mar 2016.  A quick analysis suggests the number of storms is lower on Monday with an increase through to Friday.


If this result was confirmed by a more thorough analysis it could have implications for planning for emergency response.

Data and analysis is available as a gist.




2 thoughts on “Weekly cycle of storms

  1. Luke

    That’s interesting. I did the same for Brisbane and found similar general trend (increasing from Monday to Saturday), however once I increased the region to all of Queensland the results became close to uniform.


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