The austere years of the Second World War meant that wool was in very short supply with more and more factories being used for war work, and the majority of British and imported wool being used to make service uniforms, so women were encouraged to knit small delicate tops most often with short sleeves, which not only saved wool but also looked divine. Indeed it was seen as part of the war effort in maintaining the services morale to ensure that, as a woman, you always looked your best. It seems strange to us that so much emphasis went into looking good, but the Government held the belief that menfolk returning on leave wanted to see their ladies well dressed - it gave them something to fight for.
But I think it was the early 1950s which were the real inspirational years when it came to summer knitting patterns. During this time rationing was eased and many of the materials previously rationed became more available. Also colour came into its own, as people made a conscious decision to stay away from the drab colours of utility clothing. In this pattern from Stitchcraft magazine August 1950, the model wears a brightly coloured top, knitted in 3ply. This pattern is available from my Etsy Shop in PDF form if you would like to try it for yourself (SJB Vintage Hand Knits).
Here is another pattern from Stitchcraft magazine May 1951, with a delicate spray of knitted flowers in the cleavage it beautifully shows off the model's waspish waist, exentuated by the pillar box shaping of the sleeve tops. This is knitted in 1950's 2ply for a very delicate finish.
For further inspiration please take a look at the patterns I have available on my Etsy shop.