Over the last 5 months, the number of days where there has been measurable rain has remained remarkably constant:
- May 06: 21
- June 06: 20
- July 06: 21
- August 06: 21
- September 06: 21
So there you go. There is measurable rain (more than .2mm) every 2 days out of 3. By day, we mean a 24 hour period. So the number of daytimes where it rains is less than 2 out of 3, due to nighttime rain.
Also, when it does rain, there often isn't a lot. 0.2mm is hardly noticeable - when forecasters say "An inch of rain fell...", that's about 125 times as much as 0.2mm. Out of those five months, three had 9 days with more than 2mm, one had 7 days and one had 15. Only one day in the last five months has produced more than 20mm of rain.
This data is from Andrew Ross's weather station just down the road from here on Berneray. His weather data is also automatically pumped through to a display on the weather underground service. Further weather information pertaining to Berneray is available on the Isle of Berneray community website.
[AET] The irony is that the Outer Hebrides has the reputation of being the place in the UK with the extreme weather. But it's not. During the baking heatwaves of this summer on the mainland, when temperatures got up to 36C, it reached a comfortable mid-20's here. And when snow falls heavily elsewhere in the UK, here it (somewhat disappointingly) never lasts, due to the mild air off the atlantic.
So, extreme weather - no. That's what the mainland is for. And when the southern half of the UK has been turned into an unbearable sub-Saraha desert (otherwise known as "July"), we'll be out on the lawn, drinking G&Ts on a pleasantly warm afternoon. Cheers!