Chinese weather periods
立春 Lìchūn "Beginning of spring"
雨水 Yǔshuǐ "Rain Water"
惊蛰 Jīngzhé "Awakening of insects"
春分 Chūnfēn "Mid spring"
清明 Qīngmíng "Clear and bright"
谷雨 Gǔyǔ "Rain for the grains"
立夏 Lìxià "Beginning of summer"
小满 Xiǎomǎn "Partially filled grains"
芒种 Mángzhòng "seed sowing"
夏至 Xiàzhì "Summer Solstice"
小暑 Xiǎoshǔ "Slight Heat"
大暑 Dàshǔ "Great Heat"
立秋 Lìqiū "Beginning of autumn"
处暑 Chǔshǔ "End of heat"
白露 Báilù "White dew"
秋分 Qiūfēn "Autumn Equinox"
寒露 Hánlù "Cold dew"
霜降 Shuāngjiàng "Frost descends"
立冬 Lìdōng "Beginning of winter"
小雪 Xiǎoxuě "Slight snow"
大雪 Dàxuě "Big snow"
冬至 Dōngzhì "Winter solstice"
小寒 Xiǎohán "Slight cold"
大寒 Dàhán "Extreme cold"


What you have mentioned in your question, the hottest period, I think it is 大暑, end of July, the hottest time in Northern hemisphere.