We totally get it. Even as adults, sunny days are the ultimate temptress to take a longer lunch break or cut out of work a little early. But for kids in school, that's not an option, and staring out the window and daydreaming about recess won't get them anywhere.
Make sure that they're getting the outdoor fun that they so crave after the dismissal bell rings. Barbecue and eat dinner on the patio. Encourage them to play with the neighborhood kids. Ensuring that they get their daily dose of fun in the sun (even if it's technically dusk) after school means that they won't feel like they're missing out as much between 9 to 3.