Open two tabs on a September afternoon and search the same San Carlos zip code. One shows a median sale price near $2.75 million. The other, pulling from the same underlying market, lands around $2.16 million. Same city. Same week. A gap of roughly $590,000 on a number that's supposed to answer one question: what is a house here actually worth right now.
Both numbers are correct. They're just measuring different things, and the difference matters more than most homebuyers realize when they're stacking up Peninsula cities against each other.
Two Numbers, Two Questions
A sold-price median only counts homes that closed escrow in a given window. It answers: what did buyers actually pay for whatever happened to sell. A home-value index, by contrast, blends every property in the area, including the ones that haven't traded hands in a decade, to answer a different question: what is the typical home in this area worth, whether or not it's for sale.
In San Carlos, the sold-price median for March 2026 came in at $2,750,000, up 14.0% year over year. The broader value index for the same period sat closer to $2.16 million. That $590,000 spread isn't market noise. It's a signal that the mix of homes closing that month skewed toward the top of the city's range. White Oaks and Howard Park, San Carlos's two priciest pockets, have been supplying a growing share of recent closings, pulling the sold-price median up faster than the value index that still accounts for older, smaller homes in El Sereno, Devonshire, and Brittan Acres that aren't turning over as often.
By July 2026, San Carlos's own three-month sold-price median had drifted back down to $2.5 million, down slightly year over year. Same city, same data source, a quarter-million-dollar swing in four months. Nothing about San Carlos changed that dramatically in that window. What changed was which homes happened to close.
The City Where This Shows Up Loudest
Hillsborough makes the same point in a more extreme register. Over the three months ending May 2026, the median sale price came in at $7.1 million, up 33.4% year over year. That's the kind of number that reads like a headline: Hillsborough prices up a third in a single year.
But only 39 homes sold in Hillsborough that May, up from 34 the year before. When your entire monthly sample is smaller than a single suburban block party, one or two estate-level sales can swing the reported median by double digits without any shift in what a typical Hillsborough property is worth. A $12 million sale landing in a month that otherwise would have logged $4 million transactions doesn't mean the town got a third more valuable. It means the town had a different month.
This is the mechanism worth naming plainly. On the Peninsula, where monthly closing counts in most cities run somewhere between 40 and 175, a citywide median is closer to a spotlight than a thermometer. It tells you what happened to sell. It doesn't reliably tell you what's happening to value.
Burlingame, Split Three Ways in the Same Season
Burlingame is the cleanest illustration because its own sub-neighborhoods disagree with each other in the same reporting window. Downtown Burlingame's median sale price for February 2026 was down 32.3% year over year. Burlingame Village, a few blocks away, posted a median up 39.8% for March 2026. Burlingame Hills came in up 13.5% for November 2025. Meanwhile, the citywide figure for the three months ending April 2026 moved only 0.8%, while the broader home-value index for Burlingame showed a 9.2% gain as of July 31, 2026.
Three pockets, three different stories, one citywide average that smooths all of it into a number that describes none of it precisely. If you're comparing Burlingame to another Peninsula city using only the citywide figure, you're comparing an average of contradictions to whatever single number the other city happens to be reporting that month.
What the Real Trends Look Like Underneath the Noise
None of this means every price movement on the Peninsula is statistical noise. Some of it is a genuine, trackable fundamental, and the skill is telling the two apart.
San Carlos's Laurel Street corridor has a real story behind its premium: walkable retail, a Caltrain station in walking distance, and an ongoing 2025-2027 electrification rollout that has, if anything, strengthened demand for homes within reach of the platform. That's a fundamental driver, not a composition artifact. It shows up consistently across reporting periods rather than flipping direction every quarter.
Redwood City offers the inverse lesson. Its citywide median sale price for the three months ending August 2026 was $1.9 million, up 3.7% year over year, tracking closely with its broader value index of $1,878,298, up 5.6% as of August 31, 2026. When the sold-price median and the value index move together like that, it's a decent sign that the number reflects something closer to real market direction rather than a compositional swing. Redwood City also carries more entry-level inventory than its neighbors, with condos listing at a median near $918,000 alongside its single-family stock, which is its own kind of information: a wide range within one city tells you the citywide median is an average of very different products, not a description of any specific one.
San Mateo sits in between. Its three-month sold-price median through May 2026 was $1.8 million, up 13.0% year over year, while its broader value index showed just 1.6% growth. That gap is smaller than San Carlos's but still wide enough to suggest the sold sample is skewing toward pricier inventory rather than the whole city appreciating at that pace.
Reading the Numbers by City
| City | Sold-price median (period) | YoY change | Home-value index | YoY change |
|---|---|---|---|---|
| San Mateo | $1.8M (3 mo. ending May 2026) | +13.0% | $1,700,018 (as of 5/31/26) | +1.6% |
| Redwood City | $1.9M (3 mo. ending Aug 2026) | +3.7% | $1,878,298 (as of 8/31/26) | +5.6% |
| San Carlos | $2.5M (3 mo. ending Jul 2026) | -0.75% | $2.16M (approx., early 2026) | — |
| Burlingame | $2.9M (3 mo. ending Apr 2026) | +0.8% | $2,817,833 (as of 7/31/26) | +9.2% |
Where the two columns track closely, as in Redwood City, the citywide number is a reasonably honest description of the market. Where they diverge sharply, as in San Carlos and Burlingame, the sold-price median is telling you about the specific homes that closed, and the value index is telling you about the broader housing stock. Both are true. Neither is a substitute for the other.
What This Actually Changes for a Buyer or Seller
If you're pricing a listing, the sold-price median for your specific pocket matters more than the citywide figure. A Howard Park listing priced against San Carlos's $2.5 million citywide median is being priced against homes it doesn't compete with. If you're comparing Peninsula cities to decide where to focus a search, ask for the neighborhood-level trend and the sample size behind it before you let a single percentage change shape a decision. A 33% jump built on 39 sales deserves a different level of trust than a 3.7% move built on 177.
The San Mateo County Association of Realtors publishes monthly and quarterly county-wide sales reports drawn from MLSListings data, and they're a useful cross-check against any single portal's snapshot, precisely because they aggregate the underlying transaction data rather than a blended index.
Frequently Asked Questions
Why do different sites show different median prices for the same city? Sold-price medians only count homes that closed in a given window, while blended home-value indexes estimate the value of the entire housing stock, including homes that haven't sold recently. Both are accurate. They're built to answer different questions.
Does a rising median mean home values are rising? Not necessarily. In cities with a smaller number of monthly sales, a median can rise or fall sharply just because a different mix of homes happened to close, without any underlying shift in what a typical home is worth.
How many sales does it take before a median is trustworthy? There's no fixed threshold, but the smaller the monthly sample, the more a single high or low sale can distort the number. Hillsborough's 39 May sales moved its median 33.4% in a year. Redwood City's 177 August sales produced a much steadier 3.7% shift. More transactions generally means less noise.
If you're weighing a specific Peninsula city or a specific pocket within one, and you want the sold comps that actually apply to your street rather than a citywide blend, Breakwater Properties can walk through what the current data means for your particular home or search.
