What climate and season does iceberg lettuce need?

Iceberg lettuce is a cool season crop and needs cool weather, roughly 12 to 22 C, to form firm tight heads. In hot weather it bolts (runs to flower), turns bitter and fails to head, so timing is critical. In the plains it is a winter crop, while hill areas can grow it over a longer cool season and supply the plains in summer. It is sensitive to heat at heading more than most leafy crops, so plan so that head formation falls in your coolest weeks. Confirm exact sowing dates with your KVK for your altitude and region.