I checked out the suggested information, @Greg Jones, and found it very instructive. Thanks for the information. For others who may be interested, check this link to the Combustion Inc FAQ: https://combustion.inc/pages/faq. Look in the “Why do I need an ambient sensor?” section.For some further information on ambient temps vs. food surface temps, I’d recommend reading what Chris Young at Combustion, Inc. has to say on the subject. TLDR, the temp at/near the surface of the food will never read as high as the ambient temp of the grill. Chris Young is a scientist, and even if you are not in the market for (yet) another temp probe, there is no denying he’s done his research. As a result, his probe is much more accurate at predicting cook times, IMO.
The explanation for lower ambient sensor readings offered by Chris Young mirrors almost exactly my experience during this recent cook. My Meater+ ambient temperatures were more than 100F lower than measured by the grill thermometer as he suggested.
Now, of course, @Greg Jones, you’ve created a conundrum for me; whether to return the Meater+ to my SIL and buy a Combustion Inc. unit or to see if I can use the loaner a few more times before deciding. Life is always so complicated.