I have 2 outlets on a screened porch which sometimes get wet. They have no reset buttons. Are these safe? If not

As a general statement these should be GFI outlets. Check the breaker for these outlets to see if it is a GFCI.

Outdoor electrical outlets should have some type of covering to protect against the weather and a possible short circuit.

outdoor electrical outlet cover | eBay

Water and electricity don't mix.

They will likely operate normally, but in time they can corrode from moisture exposure. This will weaken them internally and they may disintegrate eventually leaving both an unusable outlet and one subject to an electrical malfunction such as a short or an open. Shorts cause fires. Every outlet in a wet area needs a couple of things:
It needs to be protected from moisture.
It needs to be "monitored" by some sort of GFCI device, whether it be the outlet itself or the circuit.
Protection from moisture ensures the outlet will stay dry and in a usable condition.
The GFCI device ensures that you or others will be safe when using this outlet.
It is advisable to make both changes in this situation. If you are capable of doing this safely, fine... but since you asked the question I would think your best option would be hiring some qualified electrician to make these outlets "safe".