As alang says, it depends where in Scotland. There is a huge variation in local climate because of elevation, latitude, coastal or inland, soil types, wind direction, Gulf stream, if you are on an island, and so on.
I live south of the central belt and have previously lived in Fife and in Edinburgh. I have also lived in East Anglia, Yorkshire and Anglesey, and grown veg in all those places. I have never grown veg in Somerset.
I have noticed a huge difference between the places I have grown veg - for example, in Anglesey, the big problem was sandy soil, but also heavy sea mists and howling winds. In East Anglia, we had very heavy glacial clay, which requires knowledge to grow well on, but has a good climate, if a bit dry so very productive. In Yorkshire, we were a couple of weeks behind the south, but grew great crops. In Fife, it was sea mists again, and further north and we only had a town garden so growing was restricted. In Edinburgh, the growing season was shorter, but we had a wonderful fertile allotment and could grow even tomatoes outside, if they were started indoors. Where we are now in South Lanarkshire, we are high and windy, but with lovely volcanic soil and plenty of sheep manure! I can grow just about whatever I want, but with severe limitations to the ease of growing. The season is short so many plants are started in pots indoors, and even runner beans, corn and brassicas are grown in the polytunnel. Some years tomatoes are a bit unwilling to ripen, and some years whatever is growing out in the open garden is flattened by wind or deep snow. I don't bother with growing succession crops because the later ones will not crop before the frosts. Last frost here is early June, first frost once was Aug 6th ! but usually is late September. First snow is sometimes at the end of October, but usually just one fall before Christmas, and last snow most years is in April, occasionally May. That's just here; everywhere else in Scotland is different.
I sometimes dream of the rather carefree gardening I grew up with in East Anglia, but I wouldn't move from my draughty hilltop. I like a challenge and I don't expect 100% success.
There are some lovely sheltered parts of Scotland, with beautiful gardens, so if you want to live up here, simply adapt your growing and eating habits. We grow most of what we eat: eggs, sheep, veg, fruit, herbs, but not citrus fruits or bananas - but who needs them when you have the best raspberries, every othe kind of cane fruit and wonderful strawberries.