Join the club mate, I live in Aus now and its above 30C every day. My kitchen feels like standing in an oven when I cook food and at night I sleep with a fan on my face.
It's a battle that will never get any easier, and you're going to have to fight it every day.
Might as well man up and cook the damn food.
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p.s. Reward yourself for winning those small mental battles. For instance, for the past many(many) months I've been drinking bad things... beer, fruit juice, energy drinks, etc etc. Last week I decided it was time to get back on my old(and very successful) Water + Green Tea only method. It's tough because after having a can of coke or a nice dry frosty beer, green tea and tap water isn't very appealing.
So, for 5 days if I wanted a beer/soda, I'd make myself have a mug of hot/cold green tea first. This week, I've kept the green tea and dropped the soda's and beer.
It's the bait & switch method.
Another one...
When I was struggling with cooking consistency(like you are now), I decided to reward myself every time I cooked. Find something sweet, some sort of treat or beer or whatever you want, and give yourself little rewards for doing the right thing. Then cut out the rewards, and doing the right thing won't seem as difficult.
It's like dog training, make him roll over and give him a treat every time. Then make him roll over and give him a treat sometimes.
Then make him roll over and give him a treat rarely.
Then make him roll over and you won't have to give him a treat.
Train yourself
p.s. listen to music while you're cooking. My cooking sessions can last well over two hours(i cook for a week in advance), and nothing passes the monotony like music or audiobooks.