The coming weekend "is billed by some as the most important for soybean weather this summer", Richard Feltes, vice-president of research for brokerage RJ O'Brien, said.
And ahead of it, investors booked a few more profits, but proved reluctant to give back too much ground.
Sure, the forecasts remain entrenched that the Midwest heatwave will wane, leaving more modest temperatures for Monday's US Labor Day holiday, and giving some reason to take out risk premium.
"The cold front that comes through this weekend is strong," WxRisk.com said, flagging the latest run of the GFS weather model, which forecast that temperatures in North Dakota and Minnesota will by Sunday fall to the upper 60s-mid-70s Fahrenheit.
It will be in the upper 80s in with Iowa, South Dakota and Wisconsin, cooling on Monday.
"But it's dry," the weather service said.
The take of MDA Weather Services was that "rains this weekend should improve moisture a bit across the north western and eastern Midwest, and will be most beneficial in Indiana, Ohio, and Minnesota.
"However, the rains will likely be too limited to significantly improve moisture and crop conditions across Iowa, northern Missouri, western Illinois, and western Wisconsin."
Furthermore, "the drier pattern in central and western areas next week will allow moisture shortages to build once again".
'Reasons for risk premium'
So while the end of month and last day before a long weekend both signalled position closing, and potentially profit-taking on the market's start-of-week rally, investors were reluctant to take it too far.
Weather forecasts are "still offering solid reasons for risk premium, especially in the soybeans", Benson Quinn Commodities said.
Mr Feltes said: "November soybeans are of $0.60 a bushel from recent highs, which may be enough."
Besides there were other reasons to believe the rally might not be about to collapse yet, despite a caution from Rabobank that it will likely prove "short lived".
One is the imminence of crop progress data, on Tuesday, expected to reveal falls of 2-4 points in the percentage of corn rated "good" or "excellent", and 3-5 points in soybeans, according to Mr Feltes.
(Of course, after that, could the market witness a drop on "buy the rumour, sell the fact" thinking?)
Another was a further US export sales to China, in soybeans, of 110,000 tonnes for 2013-14, indicating that high prices have not put buyers off.
Furthermore, Morgan Stanley put in a call for rises in soybean and, especially, corn prices, cautioning over the weather dent to production prospects, with Macquarie lowering its yield estimates too.
And there were no deliveries in Chicago in expiring September corn or soybean contracts, indicating that cash markets remain more attractive for sellers.
(There were 651 contracts delivered for soyoil.)
Chicago soybeans for November ended down 0.8% at $13.57 ½ a bushel, but still up 2.2% for the week.
US Commodities put in some apparently decent reasons to be cautious on corn, including the spread of harvest, with "yields in Southern Indiana on corn were reported at 240 bushels per acre", and those in Louisiana, Georgia, Texas and Arkansas "huge".
Furthermore, "world competition remains aggressive. Ukrainian corn FOB is at $4.10 a bushel for fall trading, basis December".
Indeed, basis levels were "down sharply" on corn in Gulf ports on Thursday, by $0.40 a bushe, "on an increase in the southern corn harvest", the broker added.
Still, while these factors may come more into play next week, for now December corn managed a gain, adding 0.1% to $4.82 a bushel, up 2.6% for the week.
Spring vs winter
And with corn firm, winter wheat managed to hold pretty steady too, closing down just 0.25 cents at $6.54 a bushel in Chicago for December delivery.
There were no deliveries against the expiring September contract, although the same could not be said for Minneapolis wheat, for which there were 106 lots tendered.
Spring wheat for December fell 0.4% to $7.30 ¼ a bushel in Minneapolis.
And while the International Grains Council lifted its estimate for the world harvest in 2013-14 by 4m tonnes to 697m tonnes, this remained short of the US Department of Agriculture figure of 705.4m tonnes.
'Rainfall was severely deficient'
Furthermore, ideas of the Australian harvest are fading again, with Rabobank cautioning that Australian officials could be on course to make a 2.5m-tonne downgrade to their crop estimate.
"August rainfall was severely deficient in northern New South Wales with only 3mm-12mm of rainfall on wheat farms," Gail Martell at Martell Crop Projections said.
"This was the second straight month with very dry conditions sharply reducing the wheat potential."
And ideas of demand remain decent too, supported by strong US and European export data on Thursday.
In fact, Egypt unveiled its second tender in four days, although this was not announced until after the close of markets.
In Europe, Paris milling wheat for November closed down 0.5% at E187.25 a tonne, depressed in part by a German farm ministry forecast of a 24.9m-tonne domestic crop, and saying quality was generally good too.
London wheat for November eased 0.2% to E157.75 a tonne, given some support by weaker-than-expected stocks data on Thursday.
Among soft commodities, cocoa dropped 1.7% to $2,436 a tonne for New York's December contract, given little support by a trim to 52,000 tonnes, from 60,000 tonnes, in the International Cocoa Organization estimate for the world deficit in 2012-13.
A 19,000-tonne upgrade to the production outlook more than outstripped an increased estimate for consumption.
And, with Brazil's real weakening again, it was tricking for arabica coffee and raw sugar, major Brazilian products, to rise either, in terms of dollar-denominated New York futures prices.
Best-traded arabica coffee futures for December ended down 1.1% at 116.30 cents a pound in New York, the weakest for a nearest-but-one contact since July 2009.
Raw sugar edged 0.2% down to 16.34 cents a pound for October delivery.
Macquarie flagged pressure on prices from outside Brazil too, thanks to "accelerated selling of old crop sugar stocks in India, where mills are taking advantage of record weak rupee values.
"This has led to weakening Asian premiums for physical raw sugar."