WeatherFlow Weather Meter

Weather Flow  - weather on the goPeter Detterline

I was fortunate enough to try out Weather Flow, a portable weather station for the smartphone.  The unit plugs into the audio port of the phone.   Setup was a bit challenging in that there were no real detailed instructions.  It took some time to figure out what button to push to set it up correctly.  However, once done, the unit initialized and required a compass bearing as you swung the unit around in a figure 8.  You are now ready to take accurate weather readings with your smartphone.

I was travelling across the United States, so I figured this would be a good test of its abilities.  The unit would be tested at high altitudes in the mountains, hot and humid conditions in the plains, and the dry and hot climate of the desert.   It would be subjected to thunderstorms, high winds and deep night temperatures (I am an astronomer by profession).
“What is that thing you have there”, the Park ranger asked me at Boynten State Park in Wyoming.  I smiled, and had him look over the compact Weather Flow meter.  It really looks cool, and makes you feel like a scientist.  After turning the unit on, hold it vertically for one minute as it takes its readings.  At that point you may place some descriptive notes about the weather, and then save your readings for others to see.  You may also share your weather reading through the media of your choice (email, text, facebook, etc).
So how well does it work?  The wind speed anemometer works incredible well and records the average wind speed as well as gusts.  The lowest wind speed recorded was 0 mph and the highest was 32.5 mph with a storm ripping across the lake at Boynten State Park.  Interestingly, the anemometer starts to “sing” at 20 mph, but doesn’t affect performance.
Being a travel instrument it will be subjected to all sorts of environments, and the thermometer seems most prone to error unless you take some precautions.  At 9,100 feet altitude in Westcliffe, Colorado, the Weather Flow Meter measured a temperature of 82.3°F when I brought it outside, but the local temperature read 59°F.  I took another measurement immediately and the unit measured 71.2°F.  This was also apparent when in the desert.  I keep it in the shade of the air conditioned car and measured a temperature of 96°F when the temperature outside was recorded at 110°F.  At Grand Teton, Wyoming, the unit was in the car, (but in the Sun), and measured a temperature of 100.2°F when the temperature was 60°F.  Like any thermometer, keep it in the shade and give it time to adjust.

Relative humidity is calculated by a wet and dry bulb temperature.   Well, at least back in my meteorology days in college using a sling psychrometer.  Of course there a number of ways to measure this today and my guess is that the unit uses electrical impedance with a relative humidity sensor and a dew point probe to make its measurements.  It’s not bad for such a compact instrument.  I have noticed changes compared to local instruments, but usually only a few percent.  However in a rainstorm in Ohio I recorded a relative humidity of only 74%.
The ultimate test.  My good friend, Dave Fisherowski, was kind enough to let me test the unit, and also has one of his own along with advanced weather instruments.  So we stood together outside his home letting the units acclimate for a good fifteen minutes in the shade.  The table below shows our results along with his local weather station.

Wind Speed
Wind Speed Lull
Pressure   in Hg
My Unit
5.1 mph
3.6 mph
Dave’s Unit
5.7 mph
3.8 mph
Weather Station
Doesn’t report
3.2 mph
77° F
 The results correlate fairly well with humidity showing the greatest error.  Realistically you are looking at a portable weather station for your Smartphone.  All things considered the Weather flow will give you good results.  Just take precautions with the thermometer and leave the unit out for a while before you take your reading.  This is a great instrument for school students, and people who need a quick weather analysis.  Try it out.  I know you’re going to smile when you get into that first strong wind and hear the unit sing.

Retail Unit

Close up of smart phone app readings

Dave's Quick review of the Weather Flow Meter

I, too, had a Meter to try out, but since Pete was heading cross country I knew he would give it a thorough work out and an excellent report.  I only have a couple of extra things to add


This is not an instrument meant for highly scientific use or for keeping extremely accurate weather records.  Its a general use item meant mainly for a person who might be doing work or recreation in an outdoor setting.  Boaters, fishermen, campers, hikers and hunters could find a real use for this instrument or its less expensive cousin the Wind Meter (just measures wind and direction).  Weather Weenies like me would find it useful also since I can't pack my weather instrument console and remote instruments in my pocket.  There is a niche for this in an outdoor enthusiast's life.

I like the instrument overall and have tracked it against my stationary weather instruments and the temperature, relative humidity, wind speed and direction all come within an allowable margin of error.  My only negative view deals with the air pressure reading.  It is consistently off by .3-.4 inches of mercury on every reading compared to both my very good weather instruments and when comparing it to the local NWS station about 5 miles away from my location.  The NWS station and my instruments only vary about .01-.02 inches of mercury from each other.  I have told the company about this and they said they were looking into a manual way of resetting the pressure reading.  Also, I have informed them that if you pick inches of mercury as your unit of air pressure when you post a reading online or by text to someone it reports it in millibars, which is the scientific unit for reporting and not many people might know how to interpret that reading whereas they are use to inches of Hg from weather reports on TV.  The company informed me that they would fix that in the next app update (whenever that is).  

If you are a weather weenie (like me) or an outdoor type person that would like up to the minute local weather info at the touch of your Android smartphone then this is something you will want to investigate.  I would recommend the Meter to you.


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