The effect that you have is called orange peel because it looks like the bumpy skin of an orange. If it is really minor, you may be able to get by without sanding and just spray again but probably you will want to sand the bumpsdown to where they don't show and respray. Be sure that the surface has all the sanding dust off before spraying.
If you left a spray can or the can of paint and thinner in the garage over night, it may be a little colder than 60. The product temperature is more important than air temperature. There are ways to warm a spray can but they can be dangerous. Having a spray can burst is no fun to clean up after so be very gentle if you try. It's best if you are using a spray can to just leave the can in a warmer house before use. If you really have to warm it, put the can in a pan and add hot water from your domestic water supply, which should be tempered with cold water to no more than 100 degrees. You don't want to heat the can, just warm the product/paint up to about 80-85 degrees at the hottest.
If you are using a spray compressor driven rig, use the basic principles of the above info to gently warm the paint before spraying. Be careful and do not try to control a flaming or electrical heat source. Just warm water works best.