Although not a direct answer to the OP's question, here's what I've done in the past.
Sight in at sea level, pair a compatible phone app with a Kestrel Drop D3. Use the Drop D3 to measure the atmospherics when you arrive at your destination. Using the density altitude output from the Kestrel D3 as input to the ballistics app on your phone, you're good to go. Density altitude is a function of both station pressure and temperature, so it's a much better metric for predicting bullet flight than just altitude alone. The Drop D3 is small, lightweight, always "on", with outstanding battery life. Just clip on to your day pack and forget about it until you need it.
This approach of course assumes you have a smart phone, and does require purchasing an app and a Drop D3 ($129.00), so it may not work for you. However it's a lot cheaper than purchasing a full featured Kestrel 5700 weather meter.
Hope this helps.
