Volatility forecasts for US stocks
How rough will next week be?
A barometer for stocks. It forecasts how much a stock is likely to move over the next five trading days, turns that into a likely price range, and explains it in plain words. It reads the size of moves, never their direction.
Reading for AAPL
Fair
calmer than a typical large stock; rougher than the last month.
- Needleforecast, next 5 trading days
- 22.5%
- Set handlast month, as it happened
- 15.9%
- ReferenceEWMA, the industry default
- 18.5%
Volatility is annualised: 20% means a typical day moves about 1.3%.
Likely close a week from now
Closed at 343.46 on 2026-10-16. In about two weeks out of three it should close inside the darker band a week from now (±3.2%); in about 19 out of 20, inside the lighter one.
Data provided by Twelve Data. Not investment advice.
The model predicts a weekly volatility of about 22.5% annualised, which translates to roughly a 3.2% move one‑standard‑deviation for the next five trading days. That is higher than the realised 15.9% over the past month and above the 18.5% RiskMetrics EWMA estimate. Accordingly, the close a week from now is expected to fall between about $332.8 and $354.5 about two‑thirds of the time and between $322.4 and $365.9 about 95% of the time.
Barograph · AAPL
Of 273 past forecasts here, 68% saw the next week close inside the darker band (68% would be exact).
With an account
Keep a logbook
Save the stocks you follow. Your logbook shows every one with this week's reading, and each weekday before the open a dispatch arrives by email: your readings, any stock whose weather has changed since the last one, and a short summary of its news.
- Search any US stock with ⌘K
- Add it from its reading
- Switch emails off or delete your account any time
- The morning dispatch, or one on request
AAPL
Fair
22.5% next week
was 15.9%
close 332.76–354.50
If AAPL's dial word changes before tomorrow's dispatch, it's called out at the top, followed by the news on every stock in the logbook, summarised from the headlines with links to each.
Certificate of calibration
Barometer No. 11
- Instrument
- HAR + range + down days, fitted in TypeScript on 403 S&P 500 stocks, 2005–2019
- Tested on
- 422,747 forecasts from 2020 to March 2024, unseen in fitting, and 110,181 from 2025, from a second source
- Reference
- RiskMetrics EWMA, λ = 0.94
- Result
- 13% lower QLIKE than the reference in 2020–24 (95% interval 0.051 to 0.114), better in every year
- Range check
- 71% of weeks closed inside ±1σ (68% nominal), 94% inside ±2σ (95% nominal)
- Not certified
- direction. Which way a stock moves next week is close to a coin flip, and the instrument doesn't try.
| Forecast | 2020–24 | 2025 |
|---|---|---|
| Last 20 daysthe simplest guess | 0.639 | 0.799 |
| EWMARiskMetrics, the reference standard | 0.567 | 0.715 |
| HARday, week and month, fitted | 0.527 | 0.662 |
| HAR + range + down daysthis instrument | 0.494 | 0.599 |
QLIKE is the standard score for volatility forecasts. It punishes calling a rough week calm more than the reverse. Full method and every number are in the README.