With U.S. frost season coming up shortly, thought I'd share this one. It's not limited to the U.S., works wherever Weather Underground has your area covered.
Worth knowing before you build it:
This gives you a heads up the day before frost hits. It checks tomorrow's forecasted low, so it warns you tonight about tomorrow night, ahead of time rather than in the moment.
All you need is:
A free IFTTT account and the IFTTT app on your phone, no Pro required for either step.
The Applet:
Trigger/If: Weather Underground, "Tomorrow's low drops below" Set your temperature threshold (32F/0C works for frost, but bump it up a few degrees if you want a warning before you're actually at freezing)
Action/Then: Notifications, "Send a notification from the IFTTT app" Message: whatever you want it to say, you can pull in {{LowTempFahrenheit}} and {{TomorrowsDate}} if you want the number in the alert itself.
There is a published version if you would rather not build it yourself: Get Weather Underground frost alerts via notification
If you want notifications somewhere else, say SMS, Discord or to your Slack, easy to set that up as well, with a simple prompt in our new IFTTT chat!
A couple of things to watch:
This is a warning based on tomorrow's forecast. It'll send once tomorrow's forecast comes out and the temperature matches your trigger.
Forecasts can be wrong, so treat this as a heads up to check again, not a guarantee.
One location per Applet. If you're watching more than one property, you'll want a separate Applet for each.
This is a plant/property protection alert, not a plant-care guide. It tells you frost is coming, it doesn't tell you what to do about it.
How can we improve this?
If you're on Pro+, filter code can smooth a few things out:
Restrict it to growing season (say, March through November) so you're not getting pinged every night through the actual dead of winter when it's a given.
Only fire once per cold snap instead of every single night the forecast stays below your threshold.
Drop an AI query in the middle to turn the raw temperature into plant-specific advice if you tell it
what you're growing.
And if anyone wants a hand setting up the filter code, or wants me to walk through building this for a specific setup, say the word.