Every year I meet up with cyclists shivering in the mountains of the West in the spring and early summer. Oftentimes, I load them up in my old pick-up and take them down to lower elevations. I have just been trying to convince someone who has already dealt with a snowstorm to wait before heading north – so I’ll use this forum to try to share years of experience in the West with folks who have none. There are two main factors to consider – 1) Extreme variability and 2) Extremes in altitude.
First, western weather is far more variable than weather in the East or in Europe – both during the day and from week to week. While eastern temps may range 20 degrees F in a day, they can range 40 to 50 degrees in the West. Plus temperatures can drop 20 or more degrees within minutes. Also, eastern weather is fairly predictable after mid spring – with the occasional storm. But in the West, you can have 80 degrees in mid-June and a full blizzard two days later.
Second, the geography of the West makes for climate bands with radically different weather – especially if you are riding east-west or west-east. Starting on the west coast – you have Pacific Coast climate which is cool and damp, then the Coast Range which is dryer but still pleasant, then the Central/Willamette Valleys which can be very hot in summer, then the Sierra/Cascades which can be very cold and snowy into June, then the Great Basin which can be anything, then the Rockies which can be cold and snowy into early July, then the High Plains which can be brutally hot.
All of the stuff above is for the area north of I-40. South of I-40 (actually the Mogollon Rim) you have the Sonoran Desert which shouldn’t be trifled with in mid-summer by those unfamiliar with extreme heat. This is the place to be in the West in April – maybe May – but not afterwards. I wouldn’t tour in the Sonoran in the fall until October or November.
In general, spring conditions are more dangerous in the West than fall. In spring, there is a winter’s worth of snowpack and the ground is still cold. Spring snows are usually heavier and wetter. In the fall, early snows usually are gone in a few days and the ground is still warm and relatively dry. Still, people die every year – usually hunters and hikers. I’m not aware of any cyclists off-hand, but as I said at the start, I have come across many miserable folks over the years. Why be miserable?? Plan accordingly.
Best – J
PS – Most Yellowstone roads, passes in the central Sierras, and Going to the Sun in Glacier don’t even open until late May or early June.