After a week of 33°C temperatures, we've probably all felt like hot dogs baking in the sun.
But today's post isn't about hot dogs—it's about Sun Dogs, the atmospheric kind.
Most mountaineers have seen one without knowing its name—a brilliant rainbow-like ring around the Sun, or bright patches of light on either side of it while high in the mountains.
These are called sun dogs (or parhelia) and 22-degree halos.
They form when sunlight passes through millions of tiny hexagonal ice crystals suspended high in the atmosphere. Each crystal acts like a tiny prism, bending and reflecting sunlight into one of nature's most spectacular displays.
Beautiful?
Absolutely.
But they're also one of nature's weather forecasts.
The thin, icy clouds responsible for sun dogs often arrive 24–48 hours ahead of an approaching warm front. While a halo doesn't guarantee rain or snow, it tells you that moisture is increasing high in the atmosphere and that the weather pattern is changing.
For mountain travelers, that's worth paying attention to.
Today's bluebird day can become tomorrow's low cloud, rain, poor visibility, and slippery rock. If you're planning a long alpine objective, a sun dog is a good reminder to check the forecast and think about what's coming—not just what the weather looks like right now.
There's an old weather saying:
"Ring around the Sun or Moon, rain or snow is coming soon."
Like all weather lore, it isn't perfect—but it's based on real atmospheric science.
The next time you spot a halo around the Sun, take a moment to enjoy the view.
Then remember...
The best mountain travelers don't just watch the trail.
They watch the sky too.
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