Sensing snow and freezing rain

What is measured, if anything, when there is snow or freezing rain? There is very wet snow falling right now, and there are only two WeatherFlow sets in my area. They are not far apart and it has been snowing lightly since midnight. The one is showing .5mm ‘rain’, the other .8mm. There is much more than that in the form of snow on the ground. And what happens in the case of freezing rain?

The original project specs stated that it would not be able to measure snow. Tipping bucket rain gauges also have difficulties with snow, but will give at least a hint about the water equivalent as it melts (minus evaporation).

Freezing rain is a good question. I would assume that the Sky could hear it on its acoustic sensors, but the acoustic signature would change with ice accumulation which would probably make the measurements questionable. I’ll defer to the folks at WF on this one.

On the acoustic sensor front, I seem to recall reading that WF has the ability to at least identify sleet/hail events, although it may not be displayed to the station owners yet…

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It depends on what freezing rain is. If it’s rain that freezes after it hits the surface then it is measured like any other rain. If it is in fact frozen before it hits it will depend on the speed, size and weight of each particle.

SKY was not designed to measure snow but it can distinguish rain from hail or other forms of frozen precip. We do not present this in the apps, yet, but this winter should give us enough data to add that feature. The rain accumulation values assume liquid precipitation, so when you get hail, sleet or other frozen stuff it will most likely over-report the totals.


Thank you all, for your replies. When my WF arrives and I have it set up, I’m almost looking forward to seeing what it does with freezing rain. I certainly won’t be going anywhere if it does.


Your post is just over a year old, dated November 2018.
It is now January, 2020. I just got my Sky and Air installed 2 days ago and this morning we have been having some very fluffy snow (less than an inch, it looks like).

Were you able to to add the snow detection after the 2018-2019 winter? I don’t know if I should be surprised that it has not detected any precipitation from the snow or if snow is not supposed to be detected.

Boise, Idaho
Weatherflow SW Station ID: 14600
WU Station ID: KIDBOISE421

No, if the snow packs up on the top, it won’t detect anything unless the top of the instrument is completely clear. It is very sensitive, but not enough to detect more snow, once any has accumulated. When the sun and wind take it away, you’re in business again. Same thing with freezing rain. I certainly don’t think any other instrument is capable in these conditions either.

I have also learned lately, as confirmed by the good folks at Weatherflow itself, that the Solar Unit I bought for the SKY wasn’t designed to function under continued freezing conditions. It just shuts itself off or something. So, in winter, I’ll put the batteries back in when I change from regular to winter tires, I guess. I was somewhat surprised by that discovery.


Thanks, Graham.
My Sky unit is brand new and came with the solar attachment. It also has a battery compartment – this is an either/or issue, I cannot use the solar attachment at the same time that there are batteries in the Sky, and I the battery compartment must be empty when using the sky.

I was also surprised (after I purchased my Weatherflow) to learn that the solar attachment is locked out when the temperature is below freezing. I have found this to be talked about in the Community Forum but it wasn’t all that obvious to me from the sales page either on the Weatherflow site or on Amazon. I’m not upset, but I’m just surprised at how much of a warm-weather company Weatherflow really is.

I live in Boise Idaho and, most years, we don’t really get all that much snow most years and when it does snow, it often is gone within 24 hours. (We did have a Snowzilla experience in January 2018 when we had 14 plus inches on the ground for weeks and the temperature was below freezing nearly all of the time for weeks – but that was a record-setting winter!)

Perhaps Weatherflow needs to make sure that there is a strong beta-tester presence in cold climate areas as well as in hurricane zones. The Oregon and Washington coasts, for example, usually get hurricane-strength winds every winter. The Intermountain West (including the Rocky Mountains) gets pretty cold. The Northeastern states can be very cold with strong winds as well.
And that doesn’t include the very cold of some of the Canadian Provinces (I’m not familiar with weather details from those areas but I know that there are plenty of cold-weather extremes up there). Maybe they need to test Weatherflow at some of the Ice Road Truckers sites or on some of the fishing vessels featured in various shows, lol.

C are,
All Canadian provinces, except British Columbia on the west coast, would have sustained below-freezing temperatures during winter. With a few exceptional warm spells due to climate change, the cold here can last from two to three months.

This Weatherflow in Inuvik, Northwest Territory is the northernmost in the world. It should produce the coldest temperatures, but for that reason is probably snow and ice-free much of the time. It would be hard to tell, though, as it is dark most of the day for the winter months.


SKY still won’t report snow. SKY is not capable of detecting most snow (the soft kind) because it does not produce a signal on the haptic sensor. SKY is capable of sensing “possible hail” (or sleet and other dense/solid forms of precipitation). That’s a feature we still hope to add in the future.


Due to the design of the SKY I doubt there’s anything that can be done. I don’t think there’s any weather station designed for home use that could cope with snow accumulation or freezing rain.

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I know it’s mid-July and the Heat index has been over 100 degrees F, but I’m curious if the Tempest rain sensor will be able to get a liquid measurement of the snowfall?

Not likely.

No precipitation recorded by the Tempest for this event.


not in july at least :wink:

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Hi, everyone! I’m curious if other #tempest users have been able to field test it in snow yet like @gizmoev and what their experiences have been so far. Expectation management is a good thing :slight_smile:

The Tempest sensor cannot detect snow and snow actually interferes with other sensors.

That’s what I thought from other posts. I’m tracking the haptic and wind sensors, but are there other sensors that go wonky with snow?

The snow covers the light and UV sensor. It can also interfere with wind readings.

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FWIW, for the event in my picture above, only the haptic sensor and light sensor were effected. As you can probably tell, it was a rather warm snow so it didn’t stick around long.


Are there instruments will accurately measure precipitation from snow that would work well to augment my Weatherflow?