Summer just screams "BRIGHT COLOURS", doesn't it? Can you get any more summery that lime greens, strawberry reds and orange? I think not. When bright sunny days come round the corner I always reach for the shades that just wouldn't be accepted in Winter..
Topshop nail varnishes vary so much in their shade range, they have a great range of unusual colours, like this lime green shade (below in "clique"). Link - here. At £5 each or sometimes on offer two for £9.