Humidity Change?

[Nvreloader]

Guys,
Just how much Humidity will change the ballistics of a load when shooting?

I have called the Reno weather station, 100 Miles away,
Fallon, 60 miles away and local weather station, 15 miles away, to check the Humidity levels etc.

All stations gave me very different readings, all the way from 60% to 20% etc,
when I check my 4500 Kestrel at my range, I get 10% readings,
on the same day and within 1 hr time limit etc.

I have checked and set my Kestrel to the local weather station,
several times.
So I believe the Kestrel is operating correctly.

Temps run in the range from 95* to 105*,
under a overhead covered concrete bench, open on all sides.

The range is at 4500' elevation, North facing, target impact area,
and 90% of the time, the winds will be at my 6 o'clock position,
wind run from 10 to 25+ mph.

Very rarely, I will have under a 10 mph wind,
I have had 3 days with less than 10 mph conditions,
in the last 90 days.

These weather spec's has me confused,
as I don't know what to do about it,
which is the correct way to enter in the newly acquired Litz ballistic program,
that came with his new book.

Yes, I am reading the book!!!!!

Any suggestions??

Tia,
Don

 

[JPeelen]

You are shooting at a relatively high location above sea level, where it is rather warm. This is a situation where relative humidity has a comparably large effect.
Assuming dry air at 99 degrees F, local air air density is 78.6 % of ICAO standard.
Assuming 50 % relative humidity at the same temperature, air density will go down to 77.5 percent of ICAO.

This change is the same as caused by a temperature rise from 99 to 106 degrees F in dry air.

You see, humidity influence is there, but it is quite limited. At seal level the density change would only be about half of the above.

Air humidity is very much dependent on local conditions. In the shadow it will be different from a sunny spot. Therefore, while obtaining data from weather stations is usually a good idea, in this case it can tell you nothing about your local conditions.

Hope this will give you an idea of humidity effect.

 

[Canadian bushman]

It has an effect but of all the things you enter into a ballistic solution it will be one of the smallest effects.

Unless its a huge humidity swing at long distance it will be unnoticeable. None the less, measure it and account for it, but dont sweat minor deviations in measuring humidity. Temperature and pressure are much more important.