95403 leans heavily Democratic by roughly 38 points: about 69% of voters vote Democratic and 31% Republican.
About 62% of adults in 95403 typically vote, near the U.S. average of about 62%. Among adults in 95403, ~43% vote Democratic, ~19% Republican, and ~38% don't vote. The map below shows estimated turnout by block group.
How 95403 compares
Among zip codes within 15 miles, 95403 leans more Democratic than 4 of 23 neighbors.
95403 runs about 17 points more Democratic than California as a whole.
Politics vary noticeably by block within 95403. The southeast side is the most Democratic-leaning (D+44) and the north side is the least Democratic-leaning (D+30), a spread of about 13 points.
Why 95403 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 95403, not a ranked or complete list of what matters most.
Dense areas vote Democratic. About 86% of residents in 95403 live in densely developed areas, about 50 points above the U.S. average of 36%. A high never-married share predicts Democratic voting, and about 34% of adults in 95403 have never been married, above 77% of zip codes.
Walkability and Democratic lean
Places with a highly walkable street grid tend to lean Democratic; 95403, CA sits in the top quarter nationally on this measure. A walkable street grid does not change how people vote; it mostly reflects how urban a place is.
Why turnout in 95403 looks the way it does
Renters vote less often than owners. About 45% of households in 95403 rent, about 20 points above the U.S. average of 25%. Crowded housing lines up with lower turnout, and about 8% of homes in 95403 have more than one occupant per room, above 93% 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.