With a population of around 74,500, Union City sits in California, United States. The city operates in the Pacific Time Zone.
Recent weather here gives a sense of typical conditions: in 2025, Union City recorded a mean annual temperature of 58°F, ranging from 33°F lows in January to 89°F highs in September, with about 22 inches of precipitation across the year.
View historical weather for Union City · More cities in California