Absolutely anywhere could fit those criteria! ‘Not too hot, not too cold, not too much sitting around but not too much activity (but some activity) and culture but not boring culture’ seems to be the mainstay of most of our family holidays. Places in recent years that have been a success with my kids that fit those criteria include:
St Lucia. We stayed on a chocolate farm and went down to the beach each day (it was a very covid-restricted holiday, so our accommodation choices were limited.) We also climbed the pitons, did a full day chocolate tasting and making session, hiked up to waterfalls in the jungle, and snorkelled. There would have been the options to scuba dive, sail, sunset cruises, zipwiring, or just sitting around if needed.
Turkey. We’ve been here twice, and love it. We spent a week on a filet one time, and stayed in a glamping pod on a beach the other. There are Lycian cities and ruins to look at, including some under the sea. We sea kayaked over one of them. There is also gorge-scrambling, tubing, paragliding (if you are brave!) sailing, and of course just sitting around.
Mexico. You’ve got zipwiring over the jungle, swimming in cenotes and caves, sailing, scuba, swimming with turtles, dolphins, whale sharks, there’s Mayan ruins, lost cities in the jungle and on cliff tops, it’s fabulous. Just a slight concern about security atm.
Jordan. Petra, biblical sites, the Dead Sea, scuba in the Red Sea, dune bashing, hiking, camel trekking and camping in Wadi Rum, Roman cities, crusader castles, and of course, sitting around and doing nothing if you so wish. Amazing place, my current favourite. We spent 10 days there last year and it was not long enough!
Our wish list for the future includes Costa Rica, Japan, Greece, Florida, Thailand and Vietnam.
The weather, and whether is is too hot, depends entirely on what time of year you go, of course.