95639 is a true toss-up. About 49% of voters here vote Democratic and 51% Republican.
About 55% of adults in 95639 typically vote, below the U.S. average of about 62%. Among adults in 95639, ~27% vote Democratic, ~28% Republican, and ~45% don't vote. The map below shows estimated turnout by block group.
How 95639 compares
Among zip codes within 15 miles, 95639 sits roughly in the middle of the political spectrum, with 19 neighbors leaning further in the place's direction and 7 leaning the other way.
95639 runs about 21 points more Republican than California as a whole. California leans Democratic overall, while 95639 sits closer to the political middle.
Why 95639 leans the way it does
This analysis examined 14,881 data points per zip code to find what predicts political lean and turnout. The items below are a few correlations that stood out for 95639, not a ranked or complete list of what matters most.
95639 votes against the grain of California. California leans Democratic overall, while 95639 runs about 21 points more Republican.
Paved land cover and Republican lean
Places with little paved surface tend to lean Republican; 95639, CA sits in the bottom quarter nationally on this measure. Paved ground does not change how people vote; it mostly reflects how urban and built-up a place is.
Why turnout in 95639 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 95639 is in the bottom quarter nationally for routine-care measures such as insurance coverage, preventive screenings, and dental visits. Renters vote less often than owners, and about 46% of households in 95639 rent, about 21 points above the U.S. average of 25%. Crowded housing lines up with lower turnout, and about 10% of homes in 95639 have more than one occupant per room, above 96% of zip codes. Learn more about the findings and methodology on the political spectrum map.
Nearby Zip Codes
Zip Codes with Similar Populations
Sources and methodology
Precinct-level voting records used to fit the model come from California Secretary of State, Elections, distributed by the Voting and Election Science Team. Demographic inputs come from the U.S. Census Bureau (ACS 5-year estimates and the 2020 Decennial Census). Health and environmental inputs come from the CDC (PLACES and the Environmental Justice Index). Land cover comes from the USGS and EPA. Election-day and lead-up weather come from PRISM 4km daily grids and the NOAA Global Historical Climatology Network. Mail-voting and election-administration patterns come from the MIT Election Lab's Survey of the Performance of American Elections. Block-group crime detail comes from CrimeGrade. Internet data and modeling support provided by ISPreports.org.
Modeling and analysis by the BestNeighborhood data science team. Full methodology and findings: political spectrum map.
Methodology reviewed by the BestNeighborhood data team. Last updated May 2026.