April, not so much. 

You will be attacked by a thousand evil black gnats and mosquitoes whose only existence is to torture you. 

That's why we went in March. 

I got out of work early, packed the bags with every imaginable warm thing we owned, because I knew it was going to be in the 20s at night. 

Snowpants? check. 

Chili, oatmeal, cocoa, and sandwiches? Check. 

I loaded up the car and picked him up from work. 

"Where are we going?" He asked. 

"It's a surprise," I said. 

As we fought our way through traffic and arrived at sunset, he was surprise. 

I was upset. 

All of the campgrounds had been taken for the night, and the nearest campsite was at least an hour away. 

We drove though the park gates, trying to find a reasonable place to sleep. 

Luckily, we found a large group of campers that were staying the night for the "Buffalo Run."

It was a group of ultra-marathoners and their families. Although we couldn't light fires, it was still amazing to look at the stars and eat sandwiches. 

The next day, we explored. We walked near the Salt Lake, mountain biked, and enjoyed the wildlife. 

The only close call we had, was a random bison that decided to wander on the dry part of the Salt Lake. That is no telephoto lens people. I only had my portrait lens with me.
I was less than twenty feet away from a giant, 1400 pound behemoth. 

"Oh great, I'm going to get gored by a schizophrenic bison," I thought, because the only bison I had ever seen belonged in herds.   

I tried not to make eye contact too much while it stared at me, it's pointy horns glistening in the sun.
It looked back, marked it's territory, and continued to walk across the lake bed like a drunk bison.
Whew.
I knew these bison were used to seeing people, but that one was a little too close for my comfort.
After getting over the fear of being attacked, they were absolutely gorgeous to watch.
I even found myself with a sudden urge to pet their fur.
Don't worry, I didn't.