They applied a method to select model inputs for precipitation representations, one of the most difficult climate components to simulate. (pnnl.gov)
Variable day / night cycle would not be a basis that I consider significant for difficult climate conditions since people live with that on a regular basis now. (theinconvenientskeptic.com)
Sir Christopher conceded after today's report launch that it was «difficult to imagine a more difficult climate in which to make such a proposal». (politics.co.uk)