They don’t like heat? That seems incorrect. If true, Then why are they a huge problem in TX and other southerly areas, and are only now spreading north?
https://www.cdc.gov/lyme/data-research/facts-stats/lyme-dise...
Texas has the 'Lone star Tick' primarily. But in Michigan for example we've had the Blacklegged tick (which is the main species known to carry Lyme in our state...) for a looong time.
We do all the best camping in January and February. Why, you might ask, when it's usually colder than -20 C? No ticks. Also no mosquitos, blackflies, or deerflies but mostly no ticks.
That said, whether it is hotter or cooler doesn't make much of a difference in terms of how you go about your day - you pretty much have to assume you can encounter them regardless.
Up and down cycles in temperature have always been a thing on the North American continent but climate change has made it even more variable. We will still get places where it gets very very cold but not for the consistent chunks of time it takes to set back tick populations significantly.
TLDR I don't think it's the heat or cold per se but the variance.
And yes climate change is absolutely the prime factor in their spread. Into places where they were not ever a threat before.
It impacts the population, but even a couple solid weeks of -20C weather doesn't seem to be enough to eradicate them.
Insects lay eggs, and also go dormant under fallen leaves typically. The snow + leaves insulates them, it's how live insects survive the winter.
If you watch robins in the spring, before the ground thaws, you'll see them flipping over leaves. They're eating loads of insects hiding, most still torpid from the cold.
-40C isn't a problem for ticks to live through in this way.
In terms of population, everything follows predator/prey cycles. Nothing is static. It's normal for populations to "explode", eventually predators will grow in numbers too.
I see it with noseeums here, and dragonflies. There are almost no noseeums this year, but loads of dragonflies, which means the dragonfly population will collapse, and soon (couple of years) the noseemums will be relentless. But then the dragonflies will grow in numbers, with plentiful food, and the cycle will repeat.
It's natural.
Global warming may shift habitats, but these ticks are normally here. They're not new.
You might be recalling wind chill temperatures, which would not be relevant here. They're subjective perceived temperatures for hairless apes.
However it does occasionally get to (real) -40C ish in Edmonton area, and they now have populations of blacklegged ticks. But very small populations.
Like I said above, the issue is not the absolute lows or highs, it's durations of cold, which impact their ability to recover and produce large quantities of eggs in the spring. This was literally in an article I was reading about ticks the other day, don't make me hunt for it.
Black legged ticks are not new to Ontario, but they absolutely are to places like central Alberta. And the Lone Star tick is moving north for similar reasons and will be established here in Ontario shortly as well.
I'm also 20 minutes to downtown, outside of rush hour, so I stand by the ease of saying "Ottawa".
No you don't get my address, but temperatures in cities and at airports are warmer than rural areas in winter. Where I live, I'm also higher up by several hundred feet, and it all matters. I don't blame you for checking, but the city of Ottawa encompasses a lot of rural land.
It can rain torrents in part of southern Ottawa, but Ottawa weather stations could remain dry.
My point about snow and leaves, is that if there is snow cover, they're completely happy, insulated, nestled in the leaves.
I don't doubt you read an article, and from a reputable source, I just don't buy their assertions. Lack of snow cover would be a bigger predictor than overall temp.
I know this because I farm and grow grapes and have meticulously poured over weather charts for the whole province. (Survival cut off for hybrid and wild grapes is really around -32C or so. Vinifera... maybe -20C)
I think you believe temperatures are far more homogeneous than they are. On my way home, 500M of road over a hill makes 35C turn into 31C.
And no, weather stations aren't everywhere. I think the nearest one is 20km away.