95303 leans heavily Republican by roughly 40 points: about 30% of voters vote Democratic and 70% Republican.
About 32% of adults in 95303 typically vote, below the U.S. average of about 62%. Among adults in 95303, ~10% vote Democratic, ~22% Republican, and ~68% don't vote. The map below shows estimated turnout by block group.
How 95303 compares
Among zip codes within 15 miles, 95303 leans more Republican than 10 of 16 neighbors.
95303 runs about 59 points more Republican than California as a whole. California leans Democratic overall, while 95303 is one of the few Republican-leaning pockets.
Politics vary noticeably by block within 95303. The northeast side is the most Republican-leaning (R+46) and the southwest side is the least Republican-leaning (R+27), a spread of about 19 points.
Why 95303 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 95303, not a ranked or complete list of what matters most.
95303 votes against the grain of California. California leans Democratic overall, while 95303 runs about 59 points more Republican. Low college attainment predicts Republican voting, and 95303 sits in the bottom quarter (about 15%, below 80% of zip codes).
Cancer-screening access and voter turnout
Places with low colon-cancer-screening access tend to turn out at a lower rate; 95303, CA sits in the bottom tenth nationally on this measure. Cancer screening does not drive turnout; it reflects income, insurance, and healthcare access.
Why turnout in 95303 looks the way it does
Areas with limited routine healthcare access turn out at lower rates. 95303 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 50% of households in 95303 rent, about 25 points above the U.S. average of 25%. High food insecurity lines up with lower turnout, and about 23% of adults in 95303 report food insecurity, above 85% 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.