I agree, it has been a very wet summer.
I too would prefer the dash in this case, but the comma has a long history of being used to set aside thoughts and insert pauses.
For vetbridge’s example, I would write either:
I agree. It has been a very wet summer.
I agree—it has been a very wet summer.
I agree; it has been a very wet summer.
But not with a simple comma.
I’m not saying the comma in that case is wrong. I’m pretty sure it’s okay. Stylistically, thought, I prefer the other optinos.
OK, we’ve reached agreement on the subject/verb issue. We seem to still be debating the comma issue, but with no end in sight perhaps we should just agree to disagree.
Can we move on to the much more important issue relating to the choice of the adjective “relentless”? Clearly, if rain is relentless, it does not relent. In the OP, therefore, the rain is NOT relentless; in fact the rain HAS relented and allowed for a few really nice days. Can any of you find me a more accurate adjective?
Sure. I started this mess, lemme see if I can offer up a reasonable replacement.
" The rain has been fuckin’ awful, uncle. "
" The rain has been a near-constant. "
" The rain has not relented until recently. "
" The mind-numbing sound of the raindrops on the old quonset-hut roof has nearly driven me insane. I know what they want of me- and while it’s beyond doubt that they’ll get their answers, it is incumbent upon me to provide reasonable resistance. Some say resistance is futile- I say, nay. "
“Persistent” is the first adjective that comes to mind. Perhaps “stubborn”?
I posted mine before I saw yours. I like this one, except that I would omit the last hyphenated sentence. I would also omit “nearly” in the first sentence. 
I’d word it slightly different, but still aid you in your love of commas Cartooniverse;
"We are enjoying a summer of relentless rain, which brings terrific fruit, and a few really nice days.” This still supports your original construct alluding to the rain bringing the fruit and gives you two, yes two, commas. 
"We are enjoying a summer of relentless rain and a few really nice days, which brings terrific fruit.” This points out that both the rain and the nice days bring the fruit.
Say the same thing in a parenthetical way
"We are enjoying a summer of relentless rain (which brings terrific fruit) and a few really nice days.”
Or, using a semi-colon partially satisfies your comma lust, brings more of a pause to the sentence, as well as finishes up the sentence with a bang- an exlamation mark. Kinda tells him you’re okay with the weather and love fruit.
"We are enjoying a summer of relentless rain and a few really nice days; bringing terrific fruit!”
i believe #2 would be correct but for the lack of agreement between nouns in its two sentences – “rain” in the first sentence, and “rains” in the second. The first sentence implies one long storm occasionally broken by calm. The second sugests a series of rainstorms and calms. Either sentence is correct on its own, but as parts of a paragraph they are subject to a larger set of logical rules.
#1 is incorrect because because “come” and “fruit” are not in agreement. “Come” should point to a plural form of the noun, “comes” to a singular. Acceptable structures are “comes fruit” or “come fruits”.
#3 is incorrect because because of a lack of agreement between “that” and"rains". In a different context, “that rains” might be an acceptable phrase if “rains” was functioning as a verb. In the the present context, however, “rains” must be perceived as a noun, because the phrase “of that” should be pointing to a noun. And as a plural noun. the proper pointer to “rains” should be “those”.
They are all wrong.
I’m quite certain that my terminology for for my rexplations is all wring, I am working off of dim memories from Catholic grade school, the last place I studied fprmal sentence structure.
Let’s just accept snetence one as correct. The paragraph may be unnecessary but it is not wrong.
Yours:
My correction:
With all of that rain comes terrific fruit.
OR
With all of that rain come terrific fruits.
Yours:
My correction
With all of the rain comes terrific fruit.
Yours:
My correction:
With all of that rain comes terrific fruit.
OR
With all of those rains come terrific fruits.
OR
With all of these rains come terrific fruits.
I would use a full colon instead of a semi-colon. Or even a dash.
Actually, “With all of the rains comes terrific fruit” is already correct. It’s a little awkardly worded, but still gramatically sound.
As my first post noted, when considered alone, that second sentence is indeed gramatically correct. However, when coupled with the first sentence in a paragraph, and parsing on the assumption that the first sentence is correct, the second is wrong in that “rains” disagrees with the “rain” of sentence one.
Does this mean I’ve won the parsong bee? What is my prize?
I can only thank the academy for not holding the grammar or spelling or even appropriate word selection against me. ;j
I’ve been away for a few days, and am not able to fully post in here right now.
Boyo Jim, the Academy will be in touch when the Adjudication Panel has completed its review. ( pushy… who writes their speech this early? )
As an aside, I love this thread. Be back soon.
#1 is incorrect grammatically, since it contains a disjuncture in number between subject (inverted to be at the end of the sentence) and verb.
#2 and #3 are both correct, but carry somewhat different meaning. #3 is implying that the quantity of rain is causing a plethora of particular fruiting bodies on plants – lots of apples, oranges, berries, peaches, or other fruits in the foodstuff sense.
#2 is implying that the wet summer has caused intense fructification of the plantlife, with everything growing extensively. When Jesus said, “By their fruits you shall know them,” he was not implying that they will be carrying lots of apples. Rather, “fruit” in the singular is being used, more or less literally in sentence #2, to imply lots of presumably-desirable growth, much as Jesus used the plural metaphorically to imply moral growth evinced in daily life.
First off, all three are incorrect.
AND is a coordinating conjunction. As such, a comma will only precede it when it’s in a list of 3 or more items.
So the first sentence would be grammatically correct as:
“We are enjoying a summertime of relentless rain and a few really nice days.”
The second sentence could be easily solved by conjugating the verb properly and inverting the sentence structure.
Terrific fruits come with all of that rain.
Terrific fruit comes with all of that rain.
Terrific fruits come with all of the rains.
Terrific fruit comes with all of the rains.
If you insist on keeping the sentence structure beginning with the dative “rain”, the sentence structure without a comma is correct. Just make sure that the verb is conjugated with the nominative (fruit).
With all of the rains come terrific fruits.
With all of the rains comes terrific fruit.
With all of that rain comes terrific fruit.
With all of that rain come terrific fruits
The use of the serial comma, which the first clause of your post appears to be dealing with, is undoubtedly correct. But commas are also used to separate clauses and longer phrases, and I would therefore say that your comment is incorrect as applied to the OP. (Note that the last sentence is not only a disagreement with you but an example of proper use of the comma with “and” in clausal structure.)
As for the remainder of your comment, the thrust is deriving the “terrific fruit(s)” from the rainy weather, so the inversion is syntactically sound, and your restructuring to place subject first, while grammatically and syntactically sound, is not good style, since the point of the clause is to derive the fruits from the rain, which should therefore come first.
I’ll respectfully disagree with you. The above sentence is a composite of two dependant clauses both beginning with coordinating conjunctions. It is therefore not grammatically correct. If you begin a sentence with a coordinating conjunction, it becomes a default dependent clause and the clause needs to be followed by a comma and then (eventually) an independent clause.
Coordinating conjunctions:
I’ll agree with you, but since the question wasn’t about style, which can eschew the bounds of grammar, this is irrelevant. It is more awkward to begin a sentence with a D-V-N structure (dative-verb-nominative), especially since the conjugation is contigent on the secondarily placed noun. YMMV.
I cannot disagree, stpauler, with your assertion on strict usage of conjunctions. However, good English does recognize the occasional usage of conjunctions to introduce sentences, particularly “But” used as an adversative adverb instead of its normal function as conjunction. My sentence which you parsed is therefore grammatically correct, even though contrary to the normal use of conjunctions.
Restated: “Conjunctions should not be used to start independent sentences. But there are good stylistic grounds that do not contradict proper grammar for their occasional use in the linking of independent statements into a proper expository whole.” Do you see a fault with the adversative “but” in that statement?