1961, based on this advertisement in the Benton Harbor Michigan News-Palladium on May 11, 1961.
The original mailing envelope has a return address for GRIT, a periodical for rural folks. The recipient's address includes a ZIP code, putting the mailing date some time after 1963, when ZIP codes were introduced.
Patt-o-Rama is another one of those syndicated house name patterns that are so hard to research.
Despite the "quaint old-fashioned charm," the writer still points out the functional reason for the bonnet - it shades your face. 1963 puts this bonnet pattern on the cusp of a transition from primarily functional to nostalgic or costume use. This pattern could well have served both uses. It's easy to imagine the bonnet and apron made up in red and white gingham and worn by all the ladies running booths at a church social or bazaar. Then again, this may have simply been the preferred headgear for an older woman who was accustomed to the style.
The Patt-o-rama brand is also at an interesting point in the history of unprinted patterns. By 1961 all of the big pattern companies were offering printed patterns. Patt-o-rama gamely reminds the maker that with their pattern, there are "no margins to trim," "no tracing wheels," and "no fabric waste." But again, an older woman would have grown up with unprinted patterns.
The apron pattern is entirely unremarkable (and about 10 years later, I'd make an almost identical apron in my first Home Ec class, in avocado green cotton-poly, if memory serves.)
But the bonnet was interesting.
Did sunbonnet styles change over time? How different was this bonnet from say, Butterick 5340, from the early part of the century? Superficially, not very different, as it turns out. The overall dimensions of the crowns are almost identical. The brim of the Patt-o-rama bonnet is shallower by about 1 1/2" (but still quite deep enough to completely shade the face - the illustration doesn't do justice to the depths of the brim.)
Interestingly, the Butterick bonnet confines the curtain to the back of the bonnet, while the Patt-o-rama bonnet brings the curtain across the bottom of the brim, to shade the sides of the neck.
The construction of the bonnets is a little different. The Butterick bonnet combines the crown and the curtain into a single piece, using a simple fold at neck level to create a casing for the back drawstring.
The Patt-o-rama bonnet has a separate piece for the curtain (piece J, which they call a ruffle) as well as for the drawstring casing (piece I.) Butterick assumes you'll have some narrow tape on hand to use as drawstrings. The Patto-o-rama pattern instructs you to cut and sew drawstring ties from narrow rectangles.
Patt-o-rama 8500 is a good quality pattern. The pieces are accurately cut and the notches and circles matched well. The written instructions contained a couple of slightly confusing typographical errors, and were a bit jumbled - probably from lack of space - but the construction illustrations were clear.
I made the bonnet up from some pink calico I had on hand. Chambray would provide a slightly sturdier bonnet.