History, records & the almanac
How your archive builds up, when longer chart ranges unlock, and what the almanac shows.
Every reading your station sends is stored in your site's archive, about every 5 minutes, and kept. The historic charts, the almanac, the climate reports and the chart builder are built from it.
On WeatherLink Pro/Pro+ and vendor-cloud connections, your past data is also imported, so charts can start out full. On WeatherLink Basic and pushed hardware, history starts the day you connect unless you import a history file. See WeatherLink plans & your data.
Where your archive stands
The History section on your site's dashboard Overview has a card per station: how far back the archive reaches, how many readings it holds, the oldest and newest reading, and which chart ranges are live. Below that, the import status:
| Status | What to do |
|---|---|
| Importing your WeatherLink archive | Nothing. Longer ranges appear as it goes. |
| The import starts on the next refresh | Wait about 5 minutes. |
| Fully imported | Nothing. The archive grows forward from here. |
| WeatherLink is not sharing your past readings | The free Basic plan gives no history. Upgrade WeatherLink (re-checked daily) or import a history file. |
| Pushed hardware has no archive to read back | Import a weewx, CumulusMX or CSV file for older readings. |
| Historic charts are not active on this plan | Subscribe to restart archiving. |
Only an active plan archives
Without an active trial or subscription, your site still shows live conditions and keeps everything archived, but new readings are not stored. Once the plan is active again, WeatherLink Pro/Pro+ stations fill most of the gap back in; pushed hardware needs a history file import.
Historic charts
Every reading tab has a range switcher. Longer ranges unlock as your archive grows:
| Range | Unlocks after |
|---|---|
| 24h | right away |
| 7d | 1½ days |
| 30d | 8 days |
| 90d | a month |
| 1y | about 3 months |
Longer ranges are drawn in wider steps (hourly for 7d, up to daily for 1y),
but the high and low above each chart come from your raw readings, so a short
gust is never averaged away. The range is part of the page address (for
example ?range=30d), so you can share a link to it.
For anything else, the chart builder lets visitors combine up to six series over up to 400 days.
The almanac
The Almanac tab appears once your archive holds about a week of complete days:
- All-time records, grouped as in the table below.
- This year and this month: the same records for the running period, once your archive reaches back further than it.
- Records by month ("the warmest June ever") and yearly records, once your archive spans more than one year.
- Monthly summary: each month's average high, average low, total rain and strongest gust.
- This day in history, once you have over a year of data.
- A New record today! banner when today sets an all-time record.
| Group | Records |
|---|---|
| Temperature | Hottest day, coldest night, warmest night, coldest day, highest and lowest daily average, largest and smallest daily range, highest heat index, lowest wind chill, highest and lowest dew point |
| Humidity | Highest and lowest |
| Pressure | Highest and lowest |
| Wind | Strongest gust, strongest wind, longest wind run |
| Rain | Wettest day, wettest hour, heaviest rain rate, wettest month, wettest year, longest dry spell, longest wet spell |
| Sun | Highest solar radiation, highest UV index |
- A rain day is a day with at least 0.2 mm.
- Warmest night is the highest daily minimum; coldest day the lowest daily maximum.
- Days with partial data, such as your first day, never set a record.
- A record needs its reading: no solar sensor, no solar record. Rain rate and wind run records need archive data, from WeatherLink Pro/Pro+ or an imported file, so on WeatherLink Basic and pushed hardware they stay empty.
The Reports tab next to it prints NOAA-style monthly and annual summaries from the same archive. See Climate reports.
The wind rose
The Wind tab can show a wind rose: which directions the wind came from over the last 30 days, coloured by strength. Switch it and choose 8 or 16 points under Website → Homepage → Maps and media → Wind and sky. A new site shows "Collecting wind data" until there is enough.
The weather day
By default a day runs midnight to midnight. UK and Australian observers read rain against a 9am-to-9am day, so a wet night belongs to the morning it is read. To match that, set Manage → Advanced → Weather calculations → Weather day starts at to 9am or 10am.
Changing it re-reads your whole archive in the background, which takes a few minutes. Daily rain totals, records, the almanac and the climate reports follow it; charts stay on calendar days.
Plan
Archiving, historic charts, the almanac, the reports, the chart builder and the wind rose are part of Pro and the free trial. Everything already collected is kept either way, and you can export it as CSV at any time.
Sky events
A tab listing what is coming up in the sky over your station: eclipses, meteor showers, planets, supermoons, equinoxes and solstices, for your location.
Climate reports (NOAA style)
Monthly and annual climatological summaries built from your own archive, on screen and as a plain-text download.