Here in the Kansas City area trails can seem to be closed due to wet conditions rather frequently.  It can be frustrating when you have about 4 very specific time periods when you can get to a trail for a run through out the week.  Then it rains closing the trail when you can go but it's all sunny skies and open while your stuck inside at work on a Saturday.  That's how it goes and it pays to be flexible and have other options figured out so you don't miss a workout because of a little rain.

The Trail is Closed Workouts

Switch run day for weights day.  

I don't plan out my workouts for the week, I just kinda know what I need to get done  each week then write it down once it's done.  Weights today, run tomorrow just as long as I get it all in by the end of the week.

Find a crushed gravel trail or paved trail.

These kind of trails will stay open pretty much always so they can be a go to and you still get to stay off the road.  If you are on the east side of Kansas City check out Little Blue Trace or Lake Vista Recreational.

Run the road.

I know it's not super fun dodging cars and all but you can get to know your neighborhood better this way.

Stairs

Find a set of stairs and fit your entire workout into a small space.  Check out my stair workout.

Gym

There is always the treadmill, or switch things up and try a class.