The clock of life is inside any individual and any species. Possibly your insects has ringed up to spring wrong this time, hopping it was the time, but climate was not yet the appropriate. In this case they will die quickly under the cold weather, and will go then as a valuable part of the chain of life and ecosystems (choughs).
Other way, flying insects as ladybirds have no problems, because they quickly will fly to lower places in the hot valleys.
Also, the strongest of them will do their roll about the evolution of the species. So, the most intelligent and the strongest individuals will survive till springtime come there in the high mountains.
Yet some of snow here, at Almería area (Nevada and Gádor).
Think also that perhaps this situation you have seen occurs so every year, and its absolutely normal there. It´s only an opinion.