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Introduction Paths Navigation Accommodation Route Planning Weather Kit Cuillins

6. Weather, Daylight and Webcams

(Updated June 2017)

I use the forecast to determine quite a few things: the most suitable of several planned walks, perhaps going east to get lighter or later rain; which direction to walk a given route (whether clockwise or anti-clockwise); what gear to wear and carry as spare; and also what food & drink to take & how much.

I have encountered some of the worst weather that Scotland has – gales, blizzards, white-outs, hail, heavy rain, lightning... – as well as some of the best. The average was inclement: breezy, with mist, little sun and some rain, all of which suited me fine. It would have taken decades to do all the Munros if I had been put off by the weather. I find sunny weather too hot to race up hills, but wet and very windy weather is much more unpleasant. At least with a forecast you know what to expect, and can opt for staying in doors.

Weather forecasts can be obtained from radio and television. However, the detail is not at all good, and there is a clear bias to London, which has a completely different climate from the rest of the country. The forecasters have to cover the whole country in a few minutes, and so only deal cursorily with anywhere in particular outside London. The (UK) Met Office and the Norwegian Meteorological Office produce amongst the best local ones that do not require knowledge of how to interpret charts, and MWIS produces what appear to be "worst case scenario" forecasts for large regions, issued about 16:30 for the following day.

There are lots of other web sites providing detailed weather forecasts. It certainly helps to understand pressure maps and fronts: they tell one what wind and rain to expect, and they are the most critical aspects of weather. I frequently consult a six day forecast of pressure etc. given by COLA and IGES. Animations showing existing and forecast conditions for pressure, fronts, temperatures, clouds and rain can be very helpful for understanding. The Met Office produces some, although nowadays at too small a scale and too jerky. A clearer static version is given here and by MWIS, but again the scale is a bit small. You should see clear weather as a front approaches, continuous cloud and rain with perhaps a change of wind direction and temperature at the front, changing to showers and sunny intervals after the front has passed. If the centre of the weather system is hardly moving, the weather will not change much during the day.

Some weather sites also give sunrise and sunset, moonrise and moonset times, and moon phases (the last of which is independent of location). Among these are astro.ukho.gov.uk, or sunrisesunsetmap.com and tutiempo.net. For reasons noted on my Route Plans page, these may also be useful, especially in winter. Some sites give the expected altitude of the cloud base, e.g. the MWIS.

Here are some lists of weather links:

Some sites give location-specific forecasts. These tend to be computer generated and therefore fairly accurate in the data they give, but they generally lack useful extra detail that an experienced forecaster might provide, such as how reliable the forecast is (fronts may not follow their expected paths or expected speeds), how gusty the wind might be, and how heavy or prolonged any showers might be. That is extra helpful information to look out for.

In the field, you can see if rain is about to hit because rain can be seen falling out of clouds which are coming in a direct line towards you. Rain can also pull streams of cloud down from the main cloud base. That gives you a chance to put waterproofs on before getting wet and find rocks to hide behind.

Conditions – particularly snow and cloud – can be seen on some webcams. The west is much wetter and milder than the east, and holds snow on the ground for less time. A difference of 30 miles along the direction of the wind can make a huge difference to the amount of rainfall because the clouds can off load much of their precipitation over that distance. Webcams:

Finally, avalanches can sometimes provide significant danger, especially in the Cairngorms, where I have seen huge masses of sodden snow in imminent danger of collapse. Warnings are issued by the SAIS. Snow tends to lie for a long time in dry, sunny weather, whereas heavy rain will quickly melt it.


Copyright © 2007, 2012 & 2016 Colin Walter