# History, records & the almanac

URL: https://pro-weather.com/docs/features/almanac-history

> How your archive builds up, when longer chart ranges unlock, and what the almanac shows.

The longer your site runs, the more interesting it gets. Every reading your
station produces is stored in your site's own archive - permanently - and that
archive powers historic charts, all-time records and a full climate almanac.

## How your archive builds

Pro Weather saves your station's readings on every refresh, about every 10
minutes, into a database you control through your site. Nothing is ever
trimmed or rolled up away.

- On **WeatherLink Pro/Pro+**, your past data is also **imported backwards in
  time**, so charts and records can start out full.
- On the free **WeatherLink Basic** plan, history builds **forward from the day
  you connect**.

See [WeatherLink plans & your data](https://pro-weather.com/docs/weatherlink-plans) for the full
picture.

## Historic charts

Every detail tab (Temperature, Wind, Rain, Pressure and so on) has a range
switcher: **24h, 7d, 30d, 90d and 1y**. Longer ranges unlock as your archive
grows, so a brand-new site starts with 24 hours and earns the rest:

| Range | Unlocks after roughly |
| --- | --- |
| 24h | right away |
| 7d | 1½ days of data |
| 30d | 8 days |
| 90d | a month |
| 1y | 3 months |

Longer ranges are summarised into wider steps (hourly for 7d, up to daily for
1y) so charts stay fast - but the **high/low stats shown above each chart are
computed from your raw readings**, so a 2-second gust or a momentary
temperature spike is never flattened away.

> **Shareable ranges**
>
  The selected range is part of the page address (for example `?range=30d`), so
  you can link someone straight to a monthly view.

## The almanac

The **Almanac** tab is your station's climate book. It appears automatically
once your archive holds about **a week of complete days**, and grows richer
from there:

- **All-time records**: hottest day, coldest night, wettest day, strongest
  gust, longest dry spell and the number of rain days.
- **Monthly summary**: a table per year with each month's average high, average
  low, total rain and strongest gust.
- **Yearly records**: once your archive spans more than one year.
- **This day in history**: what this date looked like in previous years, once
  you have over a year of data.
- **"New record today!"**: when today beats an all-time record - hottest day,
  coldest night, wettest day or strongest gust - the almanac celebrates it with
  a banner.

A couple of definitions the almanac uses: a **rain day** is any day with at
least 0.2 mm, and days with only partial data (like your very first day) don't
count toward records, so a half-measured day can't set a false record.

## The wind rose

The **Wind** tab can include a **wind rose**: a compass-shaped chart showing
which directions your wind has blown from over the **last 30 days**, coloured
by wind strength. Choose between an **8-point** or finer **16-point** rose
under **Settings → Weather features**, where you can also toggle the rose and
the live wind-direction compass. Like everything historic, it fills in over
time - a new site shows "Collecting wind data" until enough samples exist.

## Plan notes

Historic charts, the almanac and the wind rose are part of the **Pro plan**
and your **free trial**. Your archive itself always keeps collecting while
your site is active, and you can
[export it as CSV](https://pro-weather.com/docs/account-billing/account#export-your-data) at any time.

## Next steps

- [WeatherLink plans & your data](https://pro-weather.com/docs/weatherlink-plans)
- [Tabs & panels](https://pro-weather.com/docs/customizing/panels)
- [Units & language](https://pro-weather.com/docs/customizing/units-language)