Yes

Based on the weather in Napa County Airport, 2030 Airport Rd, Napa, CA 94558, USA as of October 17, 2017 2:31am local time

Why? Because it's not very warm out.
Current Conditions
Partly Cloudy
Temp: 57.2°F14°C
Wind: 1.3 MPH2 KPH
Precipitation: None