With a population of around 14,900, Johnstown sits in Colorado, United States. The city operates in the Mountain Time Zone.
Recent weather here gives a sense of typical conditions: in 2025, Johnstown recorded a mean annual temperature of 51°F, ranging from -15°F lows in January to 100°F highs in August, with about 16 inches of precipitation across the year.
View historical weather for Johnstown · More cities in Colorado