Mozcast
MozCast is a free SEO volatility tracker from Moz that visualizes day-to-day Google ranking changes as a weather-style temperature score.
The short verdict
- Bookmark MozCast and check it daily during ranking investigations.
- Never use MozCast alone — pair it with Google Search Console and your rank tracker.
- Ignore single-day spikes; look for sustained volatility over 3–5 days.
- Use it as a conversation starter, not a conclusion, when discussing ranking changes.
Here's how I actually use it and where it falls short.
What I'd actually use it for
- Quick pulse check when rankings drop — is it just me or the whole market?
- Spotting potential algorithm shifts before official announcements
- Historical comparison to see if today's volatility is unusual
- Client reporting to explain ranking fluctuations without panic
What it's good at
- Free and fast — no login, no setup, just a URL to bookmark
- Visual simplicity — the temperature metaphor makes it easy to grasp
- Trend context — you can compare today to the past week or month
- Broad signal — great for catching that something is happening, even if you don't know what
What it's awkward for
- Diagnosing why your specific site moved — it won't tell you that
- Proving an update — it's a volatility indicator, not a confirmation
- Short-term noise — one hot day doesn't mean a trend; you need multiple days
- Niche or local queries — the sample is broad, so local volatility might not show
Alternatives I'd consider
- Google Search Console — your own site's data, free
- AccuRanker — paid rank tracking with volatility alerts
- Semrush Sensor — similar volatility tracker with more granularity
- Algoroo — another free volatility tool focused on Google updates
Next step
Quick answers
Is MozCast free?
Yes, MozCast is completely free to use. No account or payment needed.
Does MozCast prove a Google algorithm update happened?
No. A high temperature suggests volatility, but it doesn't confirm a specific update. Always cross-check with other sources.
Sources
Primary documentation is linked directly. Anything commercial is marked nofollow.
- MozCast / Moz — Primary source for the tool, its methodology, and historical context.
- Search Engine Land — Well-known SEO publication that covered the launch and explains how MozCast works.
- Google Search Central — Authoritative source for understanding Google search systems, updates, and ranking guidance.
Notes from Callum Bennett.