Unfortunately, the maps we are using in this section are in farenheight. For this reason, you might want to have a temperature conversion scale picture or text. If you are using Netscape to read this, then you might have to press reload to see some of the text. There seems to be a bug in that browser (well actually many.. moan moan moan..). Hopefully fixed in a later version. Please tell me if you find it completely unreadable, and I will write a new Netscape aware version of the page. Other people should be okay (I've checked with three other browsers).
The UK is almost entirely surrounded by the sea, and it is the state of the sea which has probably the most influence on the weather; however, to the South and East, the continental land mass of Europe is very close across a relatively small sea, so it can directly control the United Kingdom's weather in certain circumstances.
Scotland's climate then? Temperate western fringe****. What this means is a little of everything through the whole year. Average temperatures never actually go below freezing, or zero Celsius (32 Farenheight) and never go above room temperature or 20 Celsius. Rainfall happens all year round, with most in the winter (an somewhat unusual feature, I understand from my school geography).
In the winter, the most important source of heat in the UK is the sea. The gulf stream, which originates in the Gulf of Mexico comes almost straight to the UK and totally controls the winter climate. To give some idea of the strength of the effect, other places in the same latitude range include Moscow, Edmonton (somewhat north of Calgary) and the Southernmost tip of Greenland (also Gulf Stream heated). For those of an upside down map persuasion, this is equivalent to the Southernmost tip of South America or Macquarie, far South of New Zealand. Within the country the parts furthest from the effect of the Gulf Stream become the coldest, which means the East (see the January temperature map)
What all of these averages hide is that variations in the direction of the wind can cause great variations in temperature. In particular, if winds come from Northern continental Europe or the Arctic, very cold weather can prevail (here, very cold means as much as -15 degrees. Well, we call it very cold..). Much much more detail, especially on the climbing aspects of winter weather, can be found on this in books such as Scotland's Winter Mountains by Martin Moran.
In summer, the major heat source is the sun. The seas surrounding the UK moderate the temperatures. This leads to a fairly straightforward pattern of more heat in the South than the North and cooler areas by the Sea than in the Centre of the UK. Remembering that the furthest that you can get from the sea in the UK is 40 miles, this effect is relatively weak. Again the direction of the wind is very important in controlling the weather.
Rainfall in the UK is a clearer story. Rain falls in the West; rain falls in Scotland; rain falls on the Mountains; rain falls on me... The warm water over the Gulf Stream gives up a lot of water vapour. Winds coming from that direction pass over the mountains of the West of Scotland, the Lake District or Wales. When they do this, they lose their water content as they go. Winds coming from other directions tend to cause much less rain. The South East of England is a surprisingly dry place. Rainfall is continuously available through the year, but some times are obviously worse than others. Have a look at at this comparison provided by david@threewiz.demon.co.uk (also available individually for both nairn and Fortwilliam.)
As you can see from the graph above, if you want to visit Scotland, April Through to June are the months to do it. Unfortunately, of course, most of the rest of Europe gets holidays in July. A quick look at the rainfall charts will convince you that this isn't always the best time to come for Rock climbing (though if it is a hot summer then it will be the hottest time). Many cliffs dry fast however, and it is traditional to climb many climbs in the rain. When I hear that British people are traditionalist, I sometimes doubt my nationality... Further South it's okay to come later, but still September is a truly rainy month.
Choosing when to go ice climbing is an art mainly involving the use of a crystal ball, and many many druidic incantations. Ice in Scotland forms every Monday and disappears in time for the weekend. The Cullin ridge is a target for which you aim, and only arrive in perfect conditions when the great Celtic kings of old wander among the mountains.. or something. Ben Nevis mostly has something formed, depending on how crazy you are. When it's cold, but there is no ice there is always turf climbing. I don't know how well known this is in other places, but good frozen turf has the same legendary position in Scottish climbing as perfect Nev****(accents)e seems to have in the rest of the world.
Outside Scotland, there are ice routes in Wales, the Lake District and probably London. I don't think these are worth deliberately travelling to. They seem to form for only a few days a year, but of course, if you're in the area (almost the whole of England counts here), then try it. My first ice climb was in the Lake District and was a great mixture of consolidated snow, reasonable ice, rock and turf. Since then, I have done one gully route in the Lakes ever. I have been down there fairly regularly, and tend to take ice gear just in case.
Scottish Climbing Archive