Am I being a total cow?

Same. Its been HELL but I dont think the heat is nice for everyone.

I think it’s a bit silly of her. She’ll just lose loads of business. Could she come earlier?

The only time my cleaner didn’t come was once she had moved her slot to the afternoon and it was the day of the red heat warning so at least 38 outside. Which I thought was fair

Yesterday was around 33 here. She came at 10. All fine - I did ask her and she said she likes the heat. So it is really rare to need to cancel. Just find a new cleaner.

She is unprofessional and lazy imo! Most of us just get on with work whatever the weather and temp as people are relying on us and it’s out JOB and we have to pay the bills! I’d find a new cleaner who isn’t constantly cancelling and is more professional and reliable

It sounds like she's under the misapprehension that she has the upper hand. And by thinking you'd be a cow to get rid of her only feeds her belief.

You are the employer, and like any employer you want someone who does the job you need doing. She no longer fits that requirement, as a result entirely of her own choice, so it is perfectly reasonable to terminate her employment and recruit someone else who does. That is not being a cow, that is taking a business decision that works for you. Take feelings out of it.

Move cleaners just tell her the truth. You are happy with her services but you need them when it's 25 degrees and above so have moved to someone else

This is what I'd do OP. If you find the new one is as good or better, I would dismiss her then. In the meantime, you are no worse off while she is refusing to come.

You could also get temporary/one-off cleans from a company to tide you through the hot months - surely it can't go on much past August.

Never occurred to me the cleaner wouldn't work due to the heat. Gardener maybe, but not a cleaner, she is INDOORS. I am working also!
My cleaner showed up.
Personally, I would get a different cleaner.

find someone else...thats mad.

I tried to tell my cleaner she didn’t have to come and she Insisted. I stocked up on ice lollies and cans of cold drink for her. The poster saying invest in aircon like it’s a fiver is hilarious

That's fair enough but I'm pretty sure a lot of self-employed cleaners have issues that you're not aware of. It's one of those jobs that's always available but physically very difficult. It's definitely my Plan B job if all else fails but I have chronic health issues so I'd be hanging on by a thread if I actually had to be a cleaner. So it's a bit ignorant to say that she should try working in a school because she might not even survive 30 minutes. That's not your problem of course but this is the reality for a lot of women.

Yes I can understand not wanting to clean in this heat but as you point out she is unreliable anyway , so I would find someone else

I'd quietly be looking elsewhere - being frequently let down by a cleaner would, in my mind, be worse than just getting into a schedule and doing it myself.

If I was you I'd see if I could get someone to come and do a one off clean this week. If they're not as good as your usual cleaner, keep it as a one off. If they are as good/better consider changing to them for regular cleans.
I did see where the cleaner was coming from. I'm not a professional cleaner but I am taking much longer to clean in the heat so I could understand a cleaner being worried about not being able to meet standards and potentially damaging their reputation. However, you kindly offered less work recognising the impact the heat could have but got quite a blunt response so you shouldn't be worried about her feelings or loss of work.

Does she mean 25C outside in the shade, or 25C in your house? Some houses are cooler than outside on hot days, and some are much hotter. If you want to keep her on, perhaps you could ask whether keeping your home below 25C would be enough to persuade her to come.
However, since she keeps cancelling and doesn't mind risking staying away for weeks at a time, she doesn't sound keen on working for you so probably a change would be better than hanging on.

@Rugrats2020 25°C is not an extreme temperature, it’s warm. It’s uncomfortable for physical work. But it’s not medically dangerous for most people. If she’d said “I can’t work above 30°C,” or “I need shorter shifts in heat,” that would be reasonable. But 25°C is a threshold we now hit constantly, especially in the last few summers. If she sticks to this rule, she’ll be unavailable for most afternoons, for most of June–August, and for many days in May and September. That’s not a workable arrangement.

She’s self‑employed so she can choose her limits, but you can choose your cleaner. Self‑employed means she sets her own conditions, but you’re not obligated to accommodate them if they don’t meet your needs. Her rule is her boundary. Your need for reliability is your boundary. They don’t match. That’s nobody’s fault but it’s incompatible.

You’ve just had major surgery, and for me this is the mean bit, at your most vulnerable/needy, she is letting you down. This is the part that matters most. You’re not asking for frivolous cleaning. You’re asking because you’re recovering, you physically can’t do certain tasks and you need someone dependable. She knows this. She still cancelled. That tells you everything you need to know about her reliability.

You offered reasonable adjustments, You weren’t rigid. you said do half, take breaks, sit down, I’ll make drinks. but she still said no. So it’s not about flexibility, it’s about her refusing to work in conditions that are normal for the season.

Would you be a cow for replacing her? Absolutely not. You’re not firing her for being ill, having childcare issues, having a one‑off emergency, or struggling in a heatwave. You’re replacing her because she has declared she won’t work in the conditions that exist for months of the year. That’s not sustainable. If anything, she’s the one making the decision for you.

The kindest way to handle it? Well you can keep it simple and guilt‑free:
“Thanks for letting me know. With the temperatures we’ve been having, I’m going to need someone who can work consistently through the summer. I’ll need to find another cleaner, but I wish you all the best.” No drama. No guilt. No debate.

For me the question of whether or not she has to go, rests squarely on whether you want a cleaner who works only in spring and autumn, or a cleaner who works when you actually need them? Because that’s the choice she is giving you - and you are the client, you did not employ her for irregular work.

You’re not being a cow, and she’s not being unreasonable either. This is a commercial relationship. She’s told you the basis on which she’ll provide the service, if that doesn’t work for you then you’re well within your rights to look elsewhere.

Could she be pregnant and finding the heat is effecting her more than it might usually??

But if you’re having a hard time to decide whether or not to stick with her now - when she doesn’t want to work at 25 degrees….

You’ll have no chance bringing yourself to replace her when she takes maternity leave…

I’d try and find a reliable cleaner now - when you need it!

Could you use an agency for the summer and use her in the winter? If she has an issue with you not wanting her in the summer under 25 degrees, then I'd use the agency year round.

I understand her viewpoint, and she may have her own health issues, but knowing you've had an operation, I think she could have been more flexible this week. I think she's going to find herself with significantly fewer clients.

What decent reliable cleaner? OP doesn’t have one!

so funny and so predictable!

Sack her off OP, employ someone decent, but don’t do your own cleaning.

When it was super hot I asked my cleaner not to vacuum, as there’s no way I would have vacuumed in that heat. She switched to deep clean of bathrooms instead.

Yea no that’s ridiculous. If she can’t do the job you need to find someone who can.

Absolutely this. If you’ve explored other options like working in the evening etc, there does come a point when you look for something else that suits you

Just find another cleaner, I'm sure you won't be the only one of her clients to do this. My cleaner has worked on all the hot days and has just asked to start earlier.