Where is InReach/GPSMap 66i/DarkSky weather forecast actually for?

I've been using my 66i in the mountains (Sierra Nevada in CA), where we are usually:

- not very close to any kind of official weather station, or city of any size

- often at a significantly different elevation from the the nearest city. And, the elevation can vary significantly in just a mile or two.

So, both the current weather and forecast can be much different between where I am, and that of any nearby "normal" weather station/report.

My question is: where is the weather report that inReach weather (currently powered by DarkSky) actually for? Is it actually for some point that might be a ways from and lower than my current location? If so, can we find out what that location is?

Or, is it somehow trying to compensate/interpolate the weather based on my current location and altitude?

Basically, I'm not sure how to interpret a weather report if I'm a ways from civilization, especially at altitude. And, having a report customized to my actual location is what I really need when out in the boonies. But, if it's not - then it would help to know where the report is actually for, so I can make my own estimated adjustment to the report.

E.g. recently we were camped at Grover Hot Springs, elev. 5900'. Nearest town is Markleeville, 5500'. We hiked a few miles west of the campground, to about 7700'. I got weather reports both at the campground and at our high point on the hike. The predicted high temps for the 2 forecasts were a few degrees apart, but not as much as I would expect for 1800' elevation change. I'm not clear whether the forecasts were actually localized to our actual locations, or the forecast changed between times of the two reports (the weather was a little unsettled that day).

0 twolpert over 3 years ago

In theory, the forecast is for whatever location you requested. Note that "Current Location" is magic and moves with you. All other locations are nailed down. AFAIK, iR devices simply relay whatever DarkSky gives them for the selected location and timeframe. I think there is some interpretation involved in translating the forecast to the cute little icons, but no actual massaging of the data.

It's as good (or as bad) as any other DarkSky forecast. It will probably be changing shortly in any case. When I went to check just now, I found that Apple has acquired DarkSky, cut off Android app users, and plans to kill the API at the end of 2021. At that point, I assume iR weather will change providers. But I have not seen anything on the forums about this to date.

0 Phillip G over 3 years ago in reply to twolpert

Hi - thanks for your response, which makes me realize I need to clarify something:

I was presuming that neither the iR device nor Garmin's servers were massaging the weather report in any way - after all, they're not in the weather business, and I presume smart enough not to try to be.

If there is any adjustment for the location the report is requested for (most often the current GPS location), relative to any fixed weather report locations, then it would probably be the DarkSky service making that adjustment.

What I'm asking is - does anyone really know whether any such adjustment is happening, and if not, is there any way to find out where the forecast is actually for.

I did read about Apple acquiring DarkSky - and like you, haven't seen any news about what's going to happen with Garmin and weather. I expect they won't announce anything until the change is nailed down, or perhaps even till shortly before they roll out the change. Here's hoping that it's something decent.

0 twolpert over 3 years ago in reply to Phillip G

We'll see if anyone chimes in. I have never heard anyone claim to know what DarkSky does to determine the "DarkSky location" of a particular forecast. To the outside world, it all seems like magic - which I suspect is the way DarkSky likes it.

0 CowboySlim over 3 years ago in reply to twolpert

10-4 Tom. I had the same question a while ago and checked it out as I also go to the Sierra Nevada mountains for camping. I go to Kennedy Meadows which is on the east side at 6,100 feet. I created a waypoint for its GPS location and another due east in Death Valley for a lower elevation and sent them both to Dark Sky.

IIRC, the temperature differences were appropriate for then 6,000 foot elevation difference. Phillip, If you go to an area in the western portion, you might also create a waypoint in the San Joaquin /Central Valley for comparison.

0 skyeye over 3 years ago in reply to CowboySlim

If someone finds out how to predict weather for a specific gps location reliably, he would be saving the whole world. No such thing exits so far, thought some people with big supercomputers are trying hard.

It is all just interpolation of some more or less reliable and always 'old' data.

If weather forecast for any point on the earth would exist, airplains, ships and many others would like to use it. The do not get it the same way as we normal people do not get it.