Is it
太陽光線は暖かいけどまぶしく、肌に刺すようです
or
太陽光線は暖かいけどまぶしくて、肌に刺すようです
What's the difference between くて and く?
This construction is not limited to i-adjectives. You can have similar pairs with verbs. In general, you can continue a sequence of predicates with either
彼は階段で転び、泣いた。
太陽光線は暖かいけどまぶしく、肌に刺すようです
彼は階段で転んで、泣いた。
太陽光線は暖かいけどまぶしくて、肌に刺すようです
The stem form is the neutral way of connecting predicates. It just lists predicates. On the other hand, the て-form is close to participles in English, adds additional meanings, and imposes the following restrictions:
Reference: Kuno, Susumu (1973). The Structure of the Japanese Language MIT Press.
I think it's no different than English when you use two adjectives to describe one noun, or one adverb that describes one adjective, that in turn describes one noun. Ex:
In this case, the difference in meaning is almost negligible. I think this would translate almost directly to Japanese:
At least this is how I always think of it.
However, if it were something like "unexpected" and "interesting", only "unexpectedly interesting article" makes sense ("unexpected, interesting article" doesn't). This seems to fit with Japanese in that you can't really connect adjectives with 〜くて when the meanings are "opposite" or don't really complement each other.