Hi muetzekatze,
yes, I’d go with something lighter in terms of material—so preferably cotton, bamboo, or microfiber, rather than merino or wool.
I’d also choose a light openwork pattern that looks airy and loose.
I just finished my holiday triangular shawl.
For it, I chose a lightweight cotton-polyacrylic blend that’s really soft and cozy, along with an airy openwork pattern that creates beautiful waves as you knit—both along the edge and throughout the shawl—all in colors perfect for a beach vacation.
I also have to say that I find a triangular shawl a bit more versatile, since you can wear it as a shawl or drape it over your shoulders when you’re wearing a top, for example. It’s even big enough that if you drape it over your shoulders, bring the ends forward, then back under your arms, and tie them in a knot at the back, it almost looks like a little jacket.
I hope to finish the pattern in the next few days so that many can still be knitted before summer.
Best regards
Nici