In reply to nator:
April (and even may) is a very hard time of year to predict as it can be anything from feeling like summer in the day with possible ground frosts, to being proper full on winter conditions or the typical mild wet windy westerly weather.
March is winter really for the mountain areas of the UK.
In Scotland I've learnt the hard way that June and even early July can be pretty cold at night!
Post edited at 18:00