Sure but Houston has a roof and uses it... From a 2016 article: "For the night game on July 6, the outside temperature in Houston felt like 105 degrees, but inside the air-conditioned ballpark, it was a comfortable 73 degrees." and from a 2023 article: "Houston had just seven out of 81 home games played with an open roof at Minute Maid Park last season."
Hot and dry weather usually leads to drier baseballs which travel farther when hit. The average temp at Fenway in Boston from June-September is around the 70s but more importantly it hits an average of 76 in June, 83 in July, and 80 in August.
I'm not saying Houston was an ice box but hitting in warmer temperatures should help Bregman at Fenway if it's a hot, warm day that he probably wouldn't have experienced in Houston tbh because the roofs would be closed (outside of April or some games in September per the 2023 article).