Here we go again...I've heard a bunch more excuses on why people can't fit a workout into their day.
Now it has to do with the kids being out of school, or it's too hot, or not having enough energy at the end of the day.
I can answer those three for you right now...
Take your kids outside to play, they need the fresh air and exercise just as much if not more than you do.
It's been beautiful lately, but even if you're overly sensitive to the sun and heat, most gyms are still indoors and they have the a/c on. If this isn't enough for you then make your workout revolve around swimming.
If you don't have enough energy at the end of the day, try working out first thing in the morning. For many folks, this is the preferred time of day. You can also make sure you are fueling your body with the appropriate nutrition and a decent amount of sleep.
There's always time for a workout, even if it's a short one, something (to an extent anyway) is always better than nothing.