Myths: Weather

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The weather in Dublin is generally comparable to Copenhagen and Amsterdam, both seen as cycling cities with cycling accounting for 40%+ of commuters.  Average weather conditions from BBC.co.uk shows both Copenhagen and Amsterdam have more ‘Wet Days’ (+0.25 mm) than Dublin. Amsterdam and Dublin have comparable rain fall, while Copenhagen has extreme cold weather and snow in the winter.  Outside the BBC.co.uk stats, Dublin is sometimes noted as being windy, but so is Copenhagen.

Dublin City Council’s 2005 study, Weather and Cycling in Dublin : Perceptions and Reality (PDF), shows the actual probability of getting wet while cycling in the city is low. Using detailed rainfall data between April 1 2003 and March 31 2005, and an example of a 22 minute commute in the city, the study found:

“Rainfall of 0.5mm per hour would typically be viewed as drizzle/very light rain. Using this low rainfall threshold (i.e. cumulative rainfall of 0.2mm on the 22 minute journey) the cyclist would have got wet on only 5% of trips in the morning and on 4% of trips in the evening. When higher rainfall thresholds are applied the proportion of trips where the cyclist gets wet declines very dramatically. With a threshold of 1mm over the 22 minute journey, which would be classified as moderate rainfall, the cyclist gets wet on average on only 0.6% of trips in the morning and on 0.4% in the evening”

It found the probability of getting wet is “very low,” but cyclists and motorists had “unduly pessimistic” perception of the weather. Its conclusion pointed towards addressing this in future promotion of cycling, four year later this has yet to happen:

“The survey results also show that car commuters and cyclists alike have a pessimistic view of the probability of getting wet in Dublin which is very inaccurate when viewed against actual data. There is a case for measures to address the misperception of occasional cyclists and car commuters alike regarding the true incidence of rainfall in Dublin and the probability of getting wet. This might form part of any new policy to promote cycling in Dublin”

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