Welcome to the Apple Community.
It's more than likely the phone will still have charge
You can only locate your device when it is logged into iCloud and 'Find My Phone' is enabled, additionally the device will need to be switched on (and charged) and connected to a wifi or cellular network.
Unfortunately, you cannot activate iCloud or 'Find My Phone' remotely.
If the device is wiped by you or another, you may not be able to locate the device (although some have reported they can)
Moisture may affect the phone if it's left outside.
Thank you so much for the prompt response!
I do know that it there was no precipitation that evening, but I was wondering about frost, dew or other condensation that may have occurred.
I was asking because I was told that the phone in question was located beside a road, approximately 20 miles from home, at roadside, after being in the elements for 24 hours by another member of the household using a "Find My iPhone" App and wanted to know if this was even possible. I do not know if the phone was fully charged at the time it was dropped; was just looking at the most "ideal" of scenarios...
Thank you again!