Aussie Web Analyst

I am guessing there would have been a fair few questions asked this morning why websites didn’t perform as well as expected in the UK over the weekend, possibly down around 3% to 5% against last week.  If the usual suspects (online marketing, server going down) have been eliminated, then the reason in many cases will have been the nice sunny weather we had.

There are a lot of different factors that impact on traffic levels for a website.  Common big factors are public holidays and school holidays with traffic always affected on these days.  Typically there would be a significant decline and, while it is possible that these days were actually positive for certain websites, there is a clear correlation between these days and traffic levels.  What this means is that it is not traffic for that website that is being impacted but the number of people using the internet (and their behaviour) is different for these days of the year.

A factor that leads to a similar change in user behaviour but that is harder to understand, difficult to explain and impossible to predict is the weather.  I have had numerous discussion trying to explain to management that the reason that traffic was down for a day or weekend was simply because the weather was nice.  People sometimes want a complicated explanation when the real answer can be quite simple.  My theory behind this change in behaviour is that on warm sunny days, more people are going to be outside enjoying the day and doing so for a longer period.  A lengthy and expensive piece of market research should prove this theory – or you try could looking outside on a sunny day.

There are two really tricky aspects to defining the exact impact from the weather, these being the varying weather conditions across a country (let alone the world) and an inconsistent level of change to traffic from similar changes in the weather.

For the first, it is not a significant issue in the UK or similar sized countries as the weather can be judged to be relatively consistent across the whole country.  Yes there is a large variation across the UK but simply taking London temperature will give an idea of hot, warm, mild or cold for the country.  For larger countries like the US or Australia it is more difficult as a no single population centre cannot be used to represent the whole country.  In these situations, I would recommend taking a weighted average across 3 to 5 locations to get a feel for overall weather conditions for that day (or segment the traffic for different regional areas).

The second inconsistency relates to an inability to create a formula that relates temperate and traffic.  Similar weather conditions can result in different levels of traffic, all other factors being equal.  This can be explained using logical thinking to explain the variations in website performance and how it is impacted by the weather.  What I have seen is that the decline from a hot weekend is always higher for the first hot weekend of spring or a late sunny weekend (as it was in London this weekend).  The simple explanation for this is that more people are going to spend time outdoors and away from their computers when it is the first hot weekend after the winter or potentially the last hot weekend of the year.

If you are doing weekly or monthly performance reporting, keep in mind the option of including the temperature when reporting on the warmer months.  The best site I found for historical weather data is the Weather Underground website (given current media reporting, the name is a little unfortunate) – an example here is historical data for Sept for London.  The only issue is that temperatures are in Fahrenheit but this can easily be adjusted in Excel.

Tags: Performance Reporting, Traffic Levels, Web Analysis