This makes sense from the perspective of "spending energy" vs "collecting energy" as probably coded in our systems.
Assume in winter when it's more difficult to harvest food you want to keep your energy spending low and in summer when there is more food you can afford to spend more because you can spend more.
Some rationale behind this statement could come from example from Gwern and how the immunologic system handles a cold:
"For example, in winter, we are cautious about deploying our immune resources. That’s why a cold lasts much longer in winter than it does in summer. It’s not because we’re cold, it’s because our bodies, based on deep evolutionary history reckon that it’s not so safe to use our immune resources in winter, as it would be in summer. There’s experimental confirmation of this in animals. Suppose a hamster is injected with bacteria which makes it sick - but in one case the hamster is on an artificial day/night cycle that suggests it’s summer; in the other case it’s on a cycle that suggests it’s winter. If the hamster is tricked into thinking it’s summer, it throws everything it has got against the infection and recovers completely. If it thinks it’s winter then it just mounts a holding operation, as if it’s waiting until it knows it’s safe to mount a full-scale response"
from: http://www.gwern.net/Drug%20heuristics
Having lived in both Michigan and Texas, humidity is the largest factor in high-temperature enjoyment. In high-humidity, anything over 75F is difficult. But in Texas where the humidity is lower I can easily enjoy >85F.
"For example, in winter, we are cautious about deploying our immune resources. That’s why a cold lasts much longer in winter than it does in summer. It’s not because we’re cold, it’s because our bodies, based on deep evolutionary history reckon that it’s not so safe to use our immune resources in winter, as it would be in summer. There’s experimental confirmation of this in animals. Suppose a hamster is injected with bacteria which makes it sick - but in one case the hamster is on an artificial day/night cycle that suggests it’s summer; in the other case it’s on a cycle that suggests it’s winter. If the hamster is tricked into thinking it’s summer, it throws everything it has got against the infection and recovers completely. If it thinks it’s winter then it just mounts a holding operation, as if it’s waiting until it knows it’s safe to mount a full-scale response" from: http://www.gwern.net/Drug%20heuristics
edit:typos