your soil temp is 55degs ?

His timing is ok. He'll just put a 2nd app down sooner. I shoot for Fed 14thish. I had planned on this past weekend with the rain chances but wasn't able to. I will for sure later this week/weekend. Lets say on avg pre emergent gives you a 100 day protection. Some last longer. That's why you'll see a 90 day reap on the spring schedule. It will give you a 10 day buffer to get the 2nd app out before the 100 days. Then you're pretty well covered through summer. A lot of people will use Prodiamine(Barricade) as the first app then come back and use Dithiopyr(Dimension) as the 2nd app. Dithiopyr will provide some post emergence control of crabgrass. And that's why people use it as the 2nd app. Prodiamine sticks to the soil better than Dithiopyr and one of the reasons used as the first app since it's less likely to wash away in the spring rains.

Use whatever schedule you like just remember what day you put your first app down and plan accordingly for your 2nd app. And remember these do need to be water in with about a 1/4" of water(depending on product and label instructions)

Kind of off topic but what kinda luck you have spraying 24d stuff in these temps on winter weed? Specifically trimec.

winter weeds will die when the temp gets a little warmer,mow and water. in Sept put down a pre emerg for your winter weeds

The only difference is it will take longer before you see the weeds dying off. It will still work just give it a little more time to do so.

This will stop fall weeds not winter weeds. You need to reapply a pre in December for winter weeds and annual winter grass.

Is there a better cold weather killer. I know Celsius and quinclorac need to be warmer to kill.

Not really. I would stay with the 24d. It still will work as I said but it's just quicker the warmer the temps are. If you want it quicker try to hit a warming trend of 3-4 days. Actually look for warmer nights as that will help too.

To check back on this the area I did this is outstanding, basically no weeds, crab, dallis, only burmuda filling in. I may do entire 2 acres this winter