95638 leans heavily Republican by roughly 36 points: about 32% of voters vote Democratic and 68% Republican.
About 52% of adults in 95638 typically vote, below the U.S. average of about 62%. Among adults in 95638, ~17% vote Democratic, ~35% Republican, and ~48% don't vote. The map below shows estimated turnout by block group.
How 95638 compares
Among zip codes within 15 miles, 95638 leans more Republican than 12 of 17 neighbors.
95638 runs about 56 points more Republican than California as a whole. California leans Democratic overall, while 95638 is one of the few Republican-leaning pockets.
Why 95638 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 95638, not a ranked or complete list of what matters most.
95638 votes against the grain of California. California leans Democratic overall, while 95638 runs about 56 points more Republican.
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 95638, CA sits below the national average on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 95638 looks the way it does
Crowded housing lines up with lower turnout. About 7% of homes in 95638 have more than one occupant per room, above 91% of zip codes. Low high-school completion lines up with lower turnout, and about 85% of adults in 95638 have completed high school, below 81% 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.