When packing for a backpacking trip, the potential weather is a key factor in what to bring. But if you are visiting the backcountry, standard weather web sites aren’t always helpful with their city- or zip-driven forecast searches. The elevation changes in the backcountry can have a lot of influence on the weather, and the closest city may not really match what you’ll experience on the trail.
What you may not realize is that you can search on the National Weather Service’s site based on latitudinal and longitudinal coordinates. For example, if you search for “37.875N, 119.35W” you will get the forecast for Tuolumne Meadows in Yosemite.
Last year when hiking 60 miles of the John Muir Trail, from Yosemite Valley over Donahue Pass to the Mammoth Lakes area, I used this method to track the weather in several key points along the route for weeks leading up to the hike. As I’m getting ready for another backcountry Yosemite trip, I’m doing the same thing, choosing our starting point and one point each day along the route to watch to get a feel for the fluctuations and trends. Of course, you can’t rely 100% on a forecast and should be prepared for unexpected rains, cold and other possible weather swings, but it does help give you some idea of what to expect.
Shortcut to latitude and longitude forecasts
Wikipedia is a very useful gateway to finding backcountry weather information since it includes latitude and longitude coordinates for a lot of locations, even backcountry points with direct links to weather and other location-specific information. Here’s a quick how-to:
For example, a search for “Donahue Pass” finds this page about the pass on the border with Yosemite National Park.
Click on the coordinates
In the upper right corner you will see “Coordinates” for the location you just found. Click on the numbers to go to a GeoHack page of additional links for that location, i.e. this page for Donahue Pass.
Click “Weather” link
Among the many links on the GeoHack page, you will see a link next to “National Weather Service” for “Weather.” In our Donahue Pass example, here’s the forecast page from the National Weather Service.
Of course, you could also take the coordinates and manually enter them in the search on the NWS site following this format “37.760278N, 119.248611W” but I find this more cumbersome, having to convert different coordinate formats, like 37° 45′ 37″ N, 119° 14′ 55″ W to decimal points and then enter them in the search.