I will be attending an afternoon wedding next month at a farm venue, a very well-oiled type of venue despite the rural setting. Temps so far predicted in mid-60's and attire will include a mix of Indian and Western.
In my dreams I might have the dreamy Ralph Lauren  dress and boots outfit. 
I am showing an option from what I've got in my closet now that is a dress + short boots + tights.  The dress is Adrianna Papell and boots PG gray suede. The dress was originally targeted as more winter holiday with the red, but I think would work fine since is floral and multicolor. At risk of wearing "ugly gray tights" I used the gray to be "reading" the light lavender in the dress print and bookend a gray tissue wool wrap and silvery accessories, and also the dress arms and end of hem is unlined lace-net which reads not-black. I was thinking that would be a softer theme for daylight setting. 
I know, "tall boots" would be great, and I could be in the market for same, but would need them to be my "forever" boots (almost), flat riding style for 13" calves and so think that's a tall order (!) to deal with on short notice and will risk making a hasty purchase. Plus would likely be black.
Booties are neither as close-fitting on the leg as ideal nor as flower-potty as some so in my biased mind, can work for this outdoor theme sort of like a cowboy boot would. An alternative is black tights and more fitted Munro plain black bootie or a short PG black bootie (Find).

I still fear I might be too chilly if it's actually in 60's, any breeze, clouds. I have a couple of black jackets but then would be a LOT of black. My accomodation may be to wear tights-under-tights. I'm limited to sleeveless thermal underlayer due to lace sleeves.
Also, for details, I could add some thin silver arm bangles--though all bracelets are hard to fit. One problem is I'm cheap re: bracelets since they are not my go-to jewelry, but I don't want them to LOOK cheap.

1-dress with gray tights and PG gray suede bootie. Can't find my Find for boot.
2-Hobo silver envelope clutch. This is a different style from my Hobo gala clutch but same leather. I duplicated when I found them each on sale because I get more dressy v. casual looks from them and the silver leather is pretty timeless for my wardrobe.
3-flat silver round dangle earring, clip-on! In my conceit, I think the clip is less intrusive on these (plus maybe I am too "mature" to worry) and the dress neckline and print does not lend itself as well to necklace for accessorizing. 
4-5 Outfit with gray wrap. The wrap is not very dressy but the wool knit "molds" well so stays put in a variety of configurations and is maybe-kinda warm.

I'm sorry my photo lighting is so bad; the dress Find shows the colors better and so IRL the outfit is more colorful and lighter than it appears in these photos. 

What do you think? Fire away, comments and suggestions welcome. If I'm totally off track I could go back to drawing board. I have a black pants and bootie option for lower half, but not the right tops/jackets for fall-day-outdoors.

ETA: The weather forecast is now for 80 degree high— warm, and about 15 degrees warmer than first predicted! So I won’t freeze.
I had to rethink my tights. I know I love gray opaque tights with these boots in general because I’m a low- contrast leg lover. But they don’t go with the dressier look and aren’t needed now for the temp. I tried sheer off - black and it just didn’t send me, too much contrast and I think in part because the boots aren’t real fitted on the ankle and because the boots are more casual.
Then I remembered my DK “semi- opaque “ black tights. ( no photo) They “ read” somewhere between black and dark gray because not fully opaque, and are silky- looking, slight sheen. So to me they seem to bridge the moderate dressiness of the dress but bit of weightiness of the suede bootie and are more low- contrast than a sheer dark hose. I think that will do.
I won’t have to wear a jacket but can have my wrap in my purse to be fuss- free, not wrapped up unless needed.
It’s funny because at these temps, I’ll bet the “ younger ladies” will be sporting bare legs and shoulders and happy they can wear their lightweight dresses, whilst for me, I’m happy I will only need 1, or maybe 2, layers!