When are you most likely to see snakes?

Question: When are you most likely to see snakes in the wild? I’ve heard that they all come out when it’s hot. If this is true, can you tell me the temperature at which they’re most active?
 
Answer: It is very difficult to give you a specific answer to this question – snakes live in a wide variety of different climates and vary in their temperature preferences. 
 
It's important to note that while their body temperatures are primarily determined by the temperature of their environment, snakes can modify their temperatures behaviourally; they can move in and out of the sun or retreat into the shade or underground. A snake’s body temperature can therefore be quite different from the ambient air temperature; a dark-coloured snake lying in the sun on a cool day will be much warmer than the air temperature.
 
As a general rule, snakes like to have a body temperature of between 20 and 35˚C. When their body temperatures get close to 35˚C, they seek colder retreat sites and when their body temperatures drop below 20˚C, they will move somewhere warmer, providing they can find somewhere warmer.

Snakes are much more able to tolerate cold temperatures than hot temperatures. When it gets cold, their metabolism and movement slow down. This may not be a problem if they have found somewhere safe to hide, but a slow-moving snake could be in great danger if a predator came along. Snakes may also choose to be at low temperatures if there is no real benefit to activity, such as in winter when food is scarce.

High temperatures are much more of a problem. If a snake gets too hot, it can suffer tissue and brain damage. It is therefore crucial that snakes have access to cool retreat sites in hot weather.
 
You’re therefore most likely to see snakes when it’s cool enough for them to want to warm up and the opportunity exists to warm up. At these times, snakes will seek open sunny spots such as on walking paths or exposed rocks. If it’s warm enough that snakes can get to their desired body temperature in a retreat site (under a rock for example), they’re likely to stay put. You’re therefore very unlikely to see a snake when it’s very hot. Snakes are also rarely seen when it’s very cold –there’s either little reason to be active or they’re too cold to be active.