Wet weather will somewhat influence how much moisture flour will absorb, but that’s not the problem here. Trying to substitute cake flour for all-purpose flour is the culprit, no question.
The first thing you’ll notice when substituting cake flour for all-purpose is how much less liquid it absorbs. If you use the amount your recipe usually calls for, you’ll be surprised to find that rather than dough, you’ve created something more like thick, sludgy soup. There are also other less-readily noticeable differences.
Wheat consists of protein, fat and carbohydrates, and is described as either hard or soft, depending on its protein content. The protein is what concerns us here. The proteins in flour, glutenin and gliaden, together form gluten when combined with liquid and mechanical action like mixing or kneading. Gluten is what gives strength and structure to baked goods like breads, pastry or cake, and to pasta.
Since the average consumer doesn’t consider the protein content of flour, millers usually describe their product by its properties, i.e., cake, pastry, all-purpose or bread flour. There’s even self-raising flour, which should be self-explanatory – it has leavening ingredients added, and is used for biscuits, quick breads, and cookies.
Bread dough needs a lot of structure to contain the carbon dioxide given off by fermenting yeast so it rises properly, and pastry and cake need enough to hold their shape but not so much that they’re tough. Pasta needs to be strong enough to roll out without breaking.
It follows, then, that bread flour is highest in protein at 12 to 14%. Cake flour is the lowest in protein at 6 to 8%. In addition to being lowest in protein, cake flour is also specially bleached to increase its ability to hold sugar and water, which makes for a tender product. (This bleaching process is not the same as the one that’s meant when a flour is referred to as “bleached” or “unbleached.”) All-purpose is somewhere in the middle at 10 to 12% protein.
In Italy, 00, or doppio zero, flour is used for pasta making. It’s a soft flour, not because it’s low in protein, but because of how finely it’s milled and how much of the germ and bran have been removed. Its protein content can vary, depending on what it’s used for, just like flours here. Some people seek it out for pasta-making. But Marcella Hazan, the generally acknowledged doyenne of Italian cooking in the US, finds unbleached all-purpose flour is easy to work with and produces pasta which is “plump and has marvelous texture and fragrance.” Going back to all-purpose flour for your pasta should resolve your problems.