Book 20, Question 39
Why Does Spring Arrive Later High on a Mountain?
Spring arrives later high on a mountain because higher places stay colder for longer! Snow there takes more time to melt. So spring seems to climb the mountain, one step at a time.
More fun facts
- Over 100 years ago, a scientist named Hopkins described how spring events like leaf-out get later as you go north or higher up.
- This idea is called Hopkins' bioclimatic law.
- Hopkins reported that spring is delayed by about 3.3 days for every 100 meters you climb.
- In the European Alps in the early 1960s, trees leafed out about 34 days later for every 1,000 meters of height.
- By 2016, that delay had shrunk by about 35 percent, to 22 days per 1,000 meters, as the climate warmed.
- That Alps study used about 20,000 observations of leaf-out dates for four common trees at 128 sites.
Sources: NAU, National Institutes of Health
Questions kids ask
How much later does spring come higher on a mountain?
A classic rule says about 3.3 days later for every 100 meters you climb.