Google SERP volatility by category, mid-September 2026

Semrush’s Sensor tool read Google’s overall SERP volatility at 2.1 out of 10 on September 16, 2026, a figure the tool itself describes as normal range. That single number is the one most often quoted, and it is also the one that hides the most. Broken out by category on the same day, News read 5.0 and Finance read 4.1, while Science and Health sat at 0.8. The all-categories score is an average across very different days happening in parallel.

What Semrush Sensor actually measures#

Sensor checks Google search results for a fixed set of keywords once a day and measures how much changed by the end of that day. Semrush is explicit that the scoring formula itself is proprietary: what it publishes is the resulting number, not the weighting behind it, on a scale where 0 to 2 reads low, 2 to 5 normal, 5 to 8 high and 8 to 10 very high. Scores refresh roughly every 24 hours and are shown for the United States on desktop, with separate views for mobile and for 25 individual categories. That is a real, live measurement, not a static report; the numbers in this piece are what the dashboard showed at the time of writing and will already look different by the time you check it yourself.

The spread beneath the headline number#

Category	Sensor score (Sep 16, 2026)
News	5.0
Finance	4.1
Food & Drink	3.7
Sports	3.3
Jobs & Education	2.9
Law & Government	2.8
Travel	2.6
All categories	2.1
Science	0.8
Health	0.8

Ten points on the same scale, read from the same dashboard at the same moment, span from 0.8 to 5.0. A site owner in Health who checked only the all-categories figure would have concluded nothing was happening; a site owner in News, reading the same headline number, would have missed that their own vertical was running at high on Semrush’s scale.

Why we care#

A single volatility score is a convenient shorthand, and it is also an average that can sit comfortably in the normal range while a specific vertical is well into high. If your traffic moved and the all-categories figure looked calm, the category breakdown, not the headline number, is the first thing to check against your own Search Console data before concluding nothing happened. And because Semrush’s formula is proprietary, treat any single day’s reading as one vendor’s directional signal about core update weather, not as confirmation of a specific cause.