Nelson does not change between summer time and winter time.
UTC -7 is the time zone offset for Pacific Time (PCT), Pacific Daylight Time (PDT) 又 Mountain Standard Time (MST).
The government of British Columbia refers to their time zone as Pacific Time (PCT) – not to be confused with Pacific Time (PT), which is an umbrella term for Pacific Standard Time (PST, UTC -7) and Pacific Daylight Time (PDT, UTC -6), observed on the US west coast.