Halcyon: A Modern Weather Console for Tempest

A quick update…

v1.5.3

  • New one-tap toggle on the Rainfall panel: tap the raindrop icon to switch between your sensor’s raw rain and WeatherFlow’s RainCheck-corrected rain (a check mark on the icon means corrected values are showing)
  • The toggle opens on whichever mode your Tempest app uses, so the numbers match what you see there — and if you have Precip Correction off, the raw figures now line up for every period including month and year, not just today

Can’t get radar to come up from rain panel. Clicking on it does nothing.

I’m going out on a limb here and guessing you’re on Safari?

Actually scratch that it’s not safari issue this time. So when you say it does nothing, nothing pops up like literally nothing? What browser and OS?

It’s worked fine in the past. I’m using Chrome and Windows 11 like I always have and it literally does nothing. Nothing is popping up at all.

I’m assuming you’ve closed it and reopened or refreshed already right?

Just closed Chrome all the way down and reopened. Its working again. Thanks! As an IT person, you’d think I’d know better, lol.

Small update that I think helps

version: 1.5.8

The Lightning panel now shows the last strike’s distance much larger, so it can be read from across the room

:clap: A quick thank you and a heads up on pricing

First off, a genuine thank you to everyone who’s subscribed to Halcyon so far. It means a lot, and you’re the reason this keeps moving forward.

A small heads up: the launch price is going up from $11.99/year to $14.99/year on Monday at 11:59 PM Eastern. If you’ve been on the fence, or you know someone who has, now’s the time. Anyone who subscribes before then locks in as a :dizzy: founding member:dizzy: , right alongside the rest of you.

What that means: founders get all new features at no extra cost:clinking_beer_mugs: , including the charts module I’m working on now, which is a fairly big undertaking so there’ll be a new Pro plan. You’re locked in.

Thanks again for being here early. More coming soon.

HISTORY AND CHARTS ARE HERE! :tada:

Calling this 2.0 release even though the dashboard hasn’t changed.

2026-06-20

  • Introducing Halcyon History (Plus and Founders) — your station’s entire past, not just today. Open a full history view with records, long-term charts and the patterns behind your local weather
  • Records for every metric: all-time, yearly, monthly and weekly highs and lows, each stamped with the exact date it happened — so you can see precisely when your hottest day, coldest night or windiest hour was
  • Long-term charts reveal the rhythms a single day can’t show — heatmaps and seasonal patterns make it easy to compare this month against the same month in years past, and a wind rose shows where your wind really comes from
  • Import your full history from WeatherFlow once, then explore it any time — mark notable days with your own annotations, and export your data to CSV to keep or analyze elsewhere
  • Halcyon surfaces standout moments on its own — your wettest hour, your calmest stretch, your biggest temperature swing — right at the top of your records

BTW I discovered an anomaly in the historical data page.

Quite the change to go from -39F to 138F in a single day. The Tempest history shows no such data.

This is for Tempest . I did not import any other station’s data.

Good catch, and you’re right that it’s not real. On May 5, 2023 your Tempest had an off day: for that one date its readings were degraded. A lot of values came through missing or stuck, and the temperature channel reported a string of impossible numbers (down to −39 °F and up to 138 °F in bursts) before returning to normal. The real temperature that day was in the high teens °C. The days before and after look completely normal and the battery was healthy throughout, so it appears to be a one-day device hiccup rather than an ongoing or power problem.

Why the Tempest app doesn’t show it: its History view runs the data through a cleaning pass that hides momentary glitches. Our Charts page currently plots the raw, unfiltered feed. Great for fidelity, but it means a hiccup like this can show up as a false “record.”

Two things we’re doing about it. First, a filter to screen out physically-impossible readings so glitches won’t surface as records or distort the charts. Second — the part your report nudged us toward — rather than just hiding them, we’ll surface flagged anomalies in a data-health view, so you can see exactly when your station misreported. That makes it easy to tell a real record from a glitch, and if a unit starts misbehaving you’ll have the dates and values to report it to Tempest/WeatherFlow support.

I’ve pulled the full set of anomalies for that day (attached), and can send the raw minute-by-minute readings too. Given it looks like a one-day hardware hiccup, it may be worth flagging to WeatherFlow support. Happy to help you put that together. Thanks for flagging it. Exactly the kind of thing that helps us harden the data handling.

Why the Tempest app doesn’t show it: its History view runs the data through a cleaning pass that hides momentary glitches. Our Charts page currently plots the raw, unfiltered station feed. Great for fidelity, but it means a one-off hardware hiccup can show up as a false “record.”

Two things we’re doing about it. First, we’re adding a filter to screen out physically-impossible readings so these glitches won’t surface as records or distort the charts. Second, and this is the part your report nudged us toward, rather than just hiding them, we’ll surface the flagged anomalies in a data-health view, so you can see exactly when and how your station misreported. That makes it easy to tell a real record from a sensor fault, and if a sensor starts misbehaving you’ll have the dates and values on hand to report it to Tempest/WeatherFlow support.

On that note, I’ve already pulled the full set of anomalies for that day for you (attached). Thanks for flagging it. It’s exactly the kind of thing that helps us harden the data handling.

Sensor anomaly report — Eldred Acres (station 36121)

Device: Tempest 181828 · Date: 2023-05-05 (local, America/Los_Angeles)
Source: WeatherFlow device-observations API (raw, unfiltered)

Summary

On 2023-05-05 this Tempest malfunctioned for the day. Two problems, both confined to that one date:

  1. Degraded / incomplete reporting. Most sensor readings were missing or stuck. Of the 1,241 records logged that day: temperature present in only 88, pressure in 20 (a healthy day logs ~1,440), wind in 428, light/UV/solar in 37. Relative humidity was pinned at exactly 15% in 763 records (61%) — a stuck value, not a real reading.
  2. Physically-impossible temperatures. 23 readings outside any real-world range — ramping down to −39.5 °C (−39 °F) and spiking to +58.8 °C (+138 °F) — across 5 bursts. The genuine temperature that day was roughly 17–20 °C.

How May 5 compares to other days

A fully healthy day for this device is ~1,440 complete readings (one per minute, all sensors populated). May 5 stands out as corrupt; note May 12 a week later shows a different fault (an outage):

Date Rows Temp present Impossible temps Pressure present Humidity stuck at 15% State
2023-05-05 (this day) 1,241 88 23 20 763 online but malfunctioning
2023-05-12 381 381 0 381 0 offline ~17 h, then clean ¹
2023-08-14 1,439 1,439 0 1,439 0 healthy
2023-02-01 1,434 1,434 0 1,434 0 healthy

¹ On May 12 the device sent nothing from ~00:01 to 17:31 local (~17.5 h dropout), then reported cleanly every minute through midnight — a connectivity/power outage, not corruption.

Interpretation: May 5 was a one-day device malfunction — degraded reporting combined with impossible temperature output. Battery was healthy throughout (2.54–2.60 V), so it isn’t a low-battery brownout. Combined with the ~17-hour outage on May 12, this unit had a rough stretch in May 2023, which is worth reporting to WeatherFlow/Tempest support for a hardware check.

Temperature fault bursts (the impossible readings)

00:18–00:26 local — 9 readings, −15.6 °C → −39.1 °C (4 °F → −38 °F)

  • 00:18 −15.6 °C (3.9 °F)
  • 00:19 −20.9 °C (−5.6 °F)
  • 00:20 −25.3 °C (−13.5 °F)
  • 00:21 −28.9 °C (−20.0 °F)
  • 00:22 −31.8 °C (−25.2 °F)
  • 00:23 −34.2 °C (−29.6 °F)
  • 00:24 −36.2 °C (−33.2 °F)
  • 00:25 −37.8 °C (−36.0 °F)
  • 00:26 −39.1 °C (−38.4 °F)

12:09–12:15 local — 6 readings, −30.1 °C → −39.5 °C (−22 °F → −39 °F)

  • 12:09 −30.1 °C (−22.2 °F)
  • 12:11 −32.8 °C (−27.0 °F)
  • 12:12 −35.0 °C (−31.0 °F)
  • 12:13 −36.9 °C (−34.4 °F)
  • 12:14 −38.3 °C (−36.9 °F)
  • 12:15 −39.5 °C (−39.1 °F)

13:36–13:38 local — 2 readings, +58.8 °C / +49.9 °C (138 °F / 122 °F)

  • 13:36 +58.8 °C (137.8 °F) ← the “138 °F hottest day”
  • 13:38 +49.9 °C (121.8 °F)

13:51–13:56 local — 5 readings, −16 °C → −27.4 °C (3 °F → −17 °F)

  • 13:51 −16.0 °C (3.2 °F)
  • 13:53 −19.3 °C (−2.7 °F)
  • 13:54 −23.4 °C (−10.1 °F)
  • 13:55 −27.4 °C (−17.3 °F)
  • 13:56 −25.4 °C (−13.7 °F)

22:20 local — 1 reading

  • 22:20 −38.6 °C (−37.5 °F)

Note

These spikes are why Halcyon’s Records showed 138 °F / −39 °F for this day. The official Tempest app filters momentary sensor glitches out of its History view, which is why you don’t see them there.

Interesting, I wonder what was going on with the sensor then. I don’t recall replacing it. Maybe I’ll have to go through the archives and look. Does Halcyon note sensor IDs in the history?

You don’t recall exactly what you were doing on May 5th, 2023 by the minute? :smiley:

What do you mean about the sensor ID? We know what sensor it is just by the knowing what we are measuring.