ASSOS WOMEN'S BASE LAYERS
Wait! Don't cut the sleeves off your interActive Summer base layer when July rolls around! Assos makes a sleeveless version -- it's called the Hot Summer base layer and it features all the fabric and fit delights of the Summer version, but it comes sans sleeves. The soft piping on the arm holes is worlds more comfy than what you'd get by giving your Summer version the Fiskars treatment.
Assos recommends using the interActive Hot Summer base layer in a temperature range of 84 to 102 degrees. (Any hotter than that and you need to go swimming instead!) Available in sizes Small-TIR, in two colors -- Black and White.
One final note: Assos base layers are not specific to men or women. They are designed to be unisex.