Based on what you said, this is what I think you're trying to achieve.
INSERT INTO #TempTable(sCliNum, dtProc, sAssignNum, sCollectNum, cFees, cAdj1, cAdj2, year, month, day)
SELECT
sCliNum,
dtProc,
sAssignNum,
sCollectNum,
cFees,
cAdj1,
cAdj2,
DATEPART(yyyy, dtProc), -- year
DATEPART(mm, dtProc), -- month
DATEPART(dd, dtProc) -- day
FROM DailyHist