Temperature sensitivity

I’m curious how others are when seasons change. The past couple of years, I have had to adjust things dramatically with temperature changes. Here in Australia, I believe (as do many indigenous people) that we have more than 4 seasons, although because I live in the small subtropical region on the east coast, we most likely have only 2 or 3 weather type changes over a year.
In Summer, insulin works quickly and my doses seem to run out faster. But in Winter, I am really struggling with hypos.

I remember that when I was at a party some considerable years ago, I was sitting on a couch around a fire outside, and I fell asleep. The fire went out and obviously my body used its reserves to keep me warm (alcohol certainly wouldn’t have helped), and I woke up to what must have been an extremely low hypo, as I couldn’t talk! Fortunately for me, I had a friend there that knew immediately what was going on and kept bringing me cups of warm water with buckets of sugar dissolved into it.

I have been finding that of late, hypos have increased overnight which I have attributed to me turning the heater off when I go to bed. My house is not that cold overnight (around 18°C), but I can’t contribute the 1-2am hypos to anything else, considering that my ‘usual’ hypo time is generally between 4-6am and can be explainable (I’m in the process of adjusting dose times in an attempt to stop my drops at that time of day).
So I was wondering, how sensitive is everyone else to temperature and temperature changes? How have those of you that are in the Northern Hemisphere gone with the high heats that some regions have been getting?


My hypos almost always are due to exercise, or taking too much bolus or taking it too early. I don’t seem to be effected by temperature. I used to notice I’d have a spike from a hot shower but that seems to have subsided. I have not noticed going low due to cooler or colder weather though (as you do) but perhaps the reaction would be similar to a shower - hot causes spikes while cool lowers (in your case).

We have been having temps here in the 100+ F range but I don’t notice it specifically effecting my BGs, other than higher BGs caused by lower activity due to the heat.


I’ve noticed the same thing with temperature, although here its seasonal from 35 C down to -30 C, obviously with heating and AC to compensate. I just adjust my basal to compensate. I wouldn’t say its as significant as intense exercise but still impacts my basal.

I have no scientific mechanism for why it happens, but I suspect its along the lines you describe. When I’m warm, no extra energy is needed to maintain a steady body temperature. When I’m cold, especially outside, I need to burn fuel to maintain body temp.


What Karl said is a good point, if your body is working to stay warm it can make a difference.

Other things can just be differences in overall activity. For example, if you spend winter chopping firewood or do different things than you do in the summer. Like if the summer is too hot and you mostly stay indoors and are less active.

Or differences in body weight can be a factor.


I’m much more insulin sensitive in the heat and warm months. Wintertime seems to add some extra insulin resistance.

I’ve seen some post on here about our bodies having a seasonal hormonal shift that contributes to alternating resistance/sensitivity.


The heat helps me adsorp the insulin, well, that’s what I think :wink: I can’t prove it, even empirically.

I suspect we all live in different temperature regimes. I live in Oregon, I go from 15F(-10C) in the winter to extremes of 120F(50C) in the summer. I don’t think that the temperature alone is the issue; the difference in sunlight contributes to a difference in my attitude to everything. I feel great in summer, bummed in winter.

To be honest I don’t think my ability to control my BG is better in either season; it may well be, but I can’t prove that. It should be because my skin is more set up to adsorp the subcutaneous insulin when it is hot, but I’m not sure that is enough to compensate for my own set of elephants in the capillary.


Cheers to everyone for your responses.
I was simply curious about how it might affect others.

I think as me and my D get older, I’m becoming more sensitive to subtle differences. It has also been a cooler winter where I live this year, so that may also play a part in what is going on with my body.

I guess the tell will be when it starts to warm up going into the warmer months and I need to add extra insulin to my regime.


@SBee You are right on the money about the insulin being quicker in the heat. As you warm up, the capillaries dilate to keep you cool. This will cause you to absorb the insulin faster.

My worst times of year are spring and fall. I live in Michigan in the United States, and our spring and fall temps can swing between 40F and 80F (4.5C and 26.6C) and this generally causes severe hypos in me. To add to the problems, our weathermen on the local news station are only about 50% accurate on good days so guessing what adjustments you need to make for the weather can be an interesting time.

surviving these weather conditions every year has been made much easier with glucose sensors.

I hope this helps, and you definitely not alone in this.


Thanks for your insight @MichaelS.

I would suggest checking out weather underground! They rely on people’s personal weather stations for the data. I find that weather forecasts are so generalised for regions, and because the ‘official’ weather stations tend to be located in airports, which with the exception of the inland airports, are generally right on the coastline (in Australia anyway). The difference between what happens there compared to where I am, can mean the difference of up to 5°C and the humidity can also change dramatically.
I also contribute, by having my own PWS. Then I always know for sure what is going on!

I find it fascinating to see the difference in my doses between the seasons. Being halfway through winter, I have substantially reduced my insulin requirements and I think I need to continue the reductions as I am still having far too many hypos.
So far, I have reduced my daily basal by 12u (I am MDI), and that seems like a considerable amount to me. I’m looking forward to seeing my endo soon, to see what his thoughts are!

1 Like

I have often noticed:
I need more insulin when I’m out in the hot sun, even if wearing sunscreen or skin not exposed. Even a little sunburn will cause a large increase in insulin need.
I go low much more easily in the cold if I’m exercising.
We lived for some years in a house with 2 flights of stairs outside access that I ordinarily used. Carrying in groceries this way most of the year didn’t seem to affect my blood sugar. But, if I did it when the weather was around freezing or lower, I’d see a noticeable drop in my blood sugar level.


Welcome to FUD @Dxin1955. Thanks for posting, that makes our site more interesting for everyone! I am just hypothesizing, I wonder if the reduction in capillary flow during really cold weather means there is more insulin available to uptake when you do warm back up. Do you think the drop occurred while you were exposed to the cold, or after when you warmed back up?


Interesting question. In recent years, if I’m going for a long walk in the cold, I pre-program my t-slim to “exercise” or suck a lifesaver periodically (since I am in the habit of taking regular long walks, I don’t ordinarily feel the need to do that, but, in normal times, instead raise the basal if I have not walked or done something aerobic for more than 1 day). Not cold now, can’t check, but my feeling is that the lower bg could be felt while still outside.


Welcome to FUD! The more the merrier. :laughing: :+1:

This whole thread was a very interesting read. I will be mindful of everything I’ve read, being this is my first full set of seasons on Humalog or any bolus insulin. Being I was diagnosed back at the end of May, I have seemingly only learned how my blood sugars work in tandem with my insulin regimen in the hot weather. Should be interesting to see what Winter does to my levels!

@Dxin1955 that’s interesting that it wasn’t post-walking in the cold, but during that you felt the drop in BG. It’s good that you can recall though, means you’re paying attention to your body. :slightly_smiling_face: This means that you’ll be able to really zone in on your care, we look forward to getting to know you better on here!


The heat from a hot bath always makes my sugars go up, I think it has to do with the blood flow around the Dexcom sensor being increased, but I’m no scientist.

I struggle to keep my feet warm CONSTANTLY. But have been told there is no nerve or blood vessel damage so it’s just cold feet. This seems absurd to me, because it’s sometimes so bad I have to soak the. In hot water or blow dry them throughout the day. Still, no other diagnosis there (seen 2 podiatrists and my Endo about this).

In the crappy weather I try to keep up with the gym because outdoor walks and other activities are lessened, so that can make a difference (less movement), but nothing super noticeable.


I have had this discussion with other long-term T1s, and found that the insulin-need response to temperature varies widely. But, some of us (seemingly not all) do have a noticeable one. I only notice the going low problem the cold when I am exercising. I have raised my basal in heat waves occasionally, but there are activity-level issues there. I’ve mostly been living in the mid-atlantic region since home bg monitoring was available. I had a friend in the colder northeast who had the opposite experience: he lowered his basal in the summer and raised it in winter. But it seemed most in that long-termer group didn’t have a significant difference.


@Dxin1955 it’s definitely interesting to see how each person has responded to my post.
It’s now spring where I live, and I have started to increase my basal insulin now that the weather has started to warm up.
I do feel that it took me all winter to find the right dosages for myself, and now I have to do it again for the warmer months. I’m keeping better records of my changes in my insulin regimes this year however, so hopefully when winter starts again, I’ll be ready for it!


@PP777 mine always go up after a shower too. If I need to calibrate (I have the dexcom g5 still), then I put it off until well after I get out otherwise it will not be correct.

I struggled with cold feet and cold hands for some time and was getting weird pins and needles in my hands after sleeping, but I wasn’t sleeping on that side. I too thought it could have been neuropathy. So I went to my GP and we spoke about carpal tunnel and a whole lot of things. I was also getting restless leg symptoms.

Turns out, I was low in iron and vitamin d, so perhaps something for you to check out for yourself?


Interesting. I know I’m not anemic, was just tested, so I guess I’m not low on iron, but no idea re Vit D. I take a multi daily, and eat pretty healthy…I’ll ask my doctor about this! Thanks:)


I see the same thing; I get a positive spike after a shower. That’s a very localized skin temperature raise - maybe the water is 100F or thereabouts. On the other hand when I swim I don’t see a rise. I pretty much only swim when the water is 80F or more (the heat pump on the swimming pool is most of my electric bill) but then I see the expected drop from exercise over the next few hours.

I came to the same conclusion as you - my G6 is very sensitive to localized temperature changes.

I don’t notice particular feelings of cold in my extremities, I do have signs of diabetic neuropathy. It causes lack of temperature sensitivity, not excessive sensitivity. It causes other weird sensations as well, fortunately I haven’t experienced those yet.

Sensitivity to cold can be a sign of reduced blood flow; an extreme example is Raynaud’s Syndrome. Sufferers have excellent nerves but defective blood supply. I think in a lesser form it’s a general problem faced by those of us who are getting older; our whole plumbing system isn’t working as well as it used to.

I use heated gloves while skiing (hey! I don’t like cold.) Heated insoles and heated socks are readily available on Amazon; might be worth a try.


Yes, definitely! When I was pregnant and had GDM, there were a few 100+ degree days, and I didn’t have an air conditioner at the time (yes, I know, it was dreadful). While I did try to stay as cool as I could (drove around in an air-conditioned car, stood in front of a good fan, ate ice cubes, etc.), I did notice that my blood sugar levels SKYROCKETED. Someone on my diabetes treatment team told me that I should expect to have to pre-bolus a lot more on exceedingly hot days than otherwise. Not sure if this just applies to pregnant ladies, or to everyone diabetic in general, but that was my experience.