For context I work in a grocery store, and the entire fall-winter time I can't recall seeing a single preggo in the store at all. Now that it's beginning to warm up lately, I've seen a lot more. I believe I saw three in one shift, and one today as I left a different store. 

It seems to me that most come out in warmer weather, or it's just easier to single them out since there is less layers.

I see them all the time, regardless of the time of year. Afaik, the weather doesn't affect anything either. I see the same amount of pregnant women at the dead of winter as when it's 100 degrees outside.

i see more that i am employed, but it is still sparingly

I gotta go with spring, summer, and fall season I notice a lot more pregnant women coming out

Spring or summer. July to October tends to be the most popular birth times in the US too.

Where I live in So CA (the desert region), pregnancy seems to occur more commonly from Oct-Apr when the weather is cooler and in a mild, warm climate. I was born in Feb. and my brother the following year in Apr., but some of my family and personal friends (or their female partners) were fine with being pregnant in the summers. Today on Easter weekend, it's nearing 100 degrees high!