In reply to JackM92:
I don't know any of any crag that holds snow on top through the summer. A few in the Cairngorms (i.e. Sputan Dearg, Creagan Etchachan) and on Ben Nevis may have patches on approach slopes but these are not problematic - in fact on a hot day can be quite refreshing to belay by. Grab a spiky rock for an axe if you need. We've had a dry winter and spring. Folk have have been climbing on many of the mountain crags over the past month of so. Just be flexible and willing to drive.