cold last night

Yesterday I saw a couple of guys at work cleaning up the swimming pool and arranging the pool chairs. Last week they hid all the pool chairs and yesterday they put them back, I wondered why. It was cold yesterday so I did not think any one would want to swim in the pool. The guys that clean up the swimming pool were also trying to put a caution sign on the swimming pool fences. I thought about asking them but I was busy working and never got the chance. There was probably a pool party last night after I got off from work. Anyhow, it was cold last night and not good to have a pool party.