The climate in Lyons, Colorado is generally dry, with low humidity, and is as close to that perfect Colorado weather that everyone admires.
High temperatures in the summers are usually in the 80’s, yet often it tops out in the 90’s. Yet almost always, it cools off comfortably at night, with temperatures dropping into the 50’s or 60’s. A quickly passing afternoon thunder shower is more common in the spring and August. The driest weather is often July and September.
The winters are not as snowy as the higher mountains, and generally not as cold. Typical of a Colorado climate, cold and snow tends to occur in short durations, followed quickly by bright blue skies and mild temperatures. However, once in a while, there are high winds out of the west, called Chinooks. They can be un-nervy, but often bring unusually warm weather.
Unlike the higher mountains, spring time is earlier and fall lasts later. Trees will bud and leaf out in April and remain on the trees until early late October or early November. But due to Rocky Mountains proximity, a snowstorm in late April or early October does occur from time to time.
At 5,460 feet in elevation, the weather is somewhat cooler than Denver (5,280′), and warmer than areas higher in the mountains, like Estes Park. At this low mountain elevation, altitude sickness, or respiratory concerns, are no different than the Boulder and Denver metro area, yet you still have the beauty of the surrounding mountains.