This thread reminds me how we all have different perspectives & interpretations. Yes, it is s...l....o...w, as in very, but that's what I love about summer. I much prefer slow over crazy, busy, hectic. That's probably because I go to Negril to relax. It's been very slow in the summer for years. I usually stay June & July & I'm on the beach. I don't know how anyone can be in Negril in the summer w/ no AC. Not me.
As June flows into July the shower/rain patterns change & they become more frequent & earlier in the day but early July is at the mid point of that progression. Your location on the beach also makes a difference. It can be raining at Treehouse & clear as can be at Travellers. Last summer was quite interesting weather-wise. There was always a breeze so it felt very comfortable.
Being a Floridian I'm used to hot & humid in the summer. One thing I've learned through many long stays in the summer... Negril beats Tampa any day. The temperature is easily 5-7 degrees cooler during the day, as much as 8-9 degrees cooler at night. The humidity is easily 10-15% lower in Negril. As an avid weather watcher (comes w/ being a runner & a wimp in cool - below 75 - weather), Negril is MUCH more comfortable than FL, at least if you're on the beach. It'll be in the low 70's at night, upper 80's during the day, humidity in the mid-high 70's. If it's rained, the whole scenario changes... steamy.
Last summer, I was probably the only person on the beach where I stay for a week when I first arrived in June. The property's population increased & decreased over the weeks. More Jamaicans around July 4th because that's about when school is out for the summer there. I like the coziness of small groups of people vs the crowded hoards of February. If you want action, you'll find it; just not as much as other times of year. If you like relaxing, it's a great time to be in Negril. That's my take, for what it's worth.