What constitutes “chilling” behavior? A teacher calls on the boys in class more than the girls. A CEO ignores what a woman says in a meeting but listens intently when a man makes the exact same point. A conference emcee mentions a female speaker’s appearance rather than (or in addition to) her accomplishments, but feels no need to comment on the appearance of male speakers. A guy at an atheist/skeptics meeting hits on a young woman in an elevator at 4 AM, ignoring the fact that she just spent the evening talking about how she hates being objectified at such gatherings.
All these sorts of things seem tiny and insignificant by themselves, but they add up, and this produces a cumulative “chilling” effect that makes women feel unwelcome, like they don’t belong. That’s a “chilly climate.” The effect is subtle; sometimes we’re not even consciously aware of it. We just have that nagging feeling of being “less than,” unable to put our finger on why we feel that way."