September 2017 Weather Round-Up

The day-to-day weather has very little impact on the volume of visits to Jersey, but can play a major role in influencing the types of activities that visitors who are here do, and thereby, the amount of money that they spend.  Some attractions and activity providers thrive only when the sun shines, others see higher patronage on rainy days.

The following charts show how the weather in recent months compares with the thirty-year average for that month.  Bars are shaded red if, in that particular month, it was colder, wetter or duller than normal, and green if it was warmer, drier and sunnier than normal, but as referenced above not all tourism suppliers will necessarily benefit from the ‘green’ months.

wet weather west

September 2017

The average temperature in September was 15.4oC, some 2.7oC lower than last September and 1.1oC down on the thirty-year average.  Rainfall totalled 129.4mm for the month, which is almost three times as wet as September of last year and double what one could expect for the time of year.    

Looking at the number of hours of sunshine we find that the total of 175.1 hours, some 17 hours fewer than a year before, and equally below the long-term average.

In summary, the September weather was wetter, cooler and duller than one might hope for at the time of year, and certainly less favourable than was the previous September.

Averages can be misleading – you can have many values that are a bit below normal being offset by a single value that is significantly above normal.  In meteorological terms for example you could have a month during which 28 days see not a drop of rain, but three days of torrential downpours.  Statistically this might lead to an ‘average’ amount of rainfall for the month, but most visitors would not have experienced ‘average’ weather.

Looking at September there were only two days when no sunshine was recorded but a further five days when there was no more than around two hours.  Both 22nd and 23rd September witnessed around eleven hours of sunshine.

On many days during September the diurnal temperature range was quite narrow.  On only two days 4th and 5th, did the temperature exceed 20oC, but it came very close to doing so on both 23rd and 26th.  There were just four days when the minimum temperature fell below 10oC.

There were eight days with no recorded rainfall and five days with only trace amounts.  The wettest days, in descending order, were 8th, 3rd, 16th and 24th.

So the ‘averages’ perhaps paint a less upbeat picture of September weather than was the case in reality, there were not too many days that could be considered a washout, not were there many days when the sun didn’t pop out from behind the clouds at least for a short while. 

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