Try this:
=AVERAGEIFS(Sheet1!$B$2:$B$849,Sheet1!$A$2:$A$849,"<"&M130)

Signature
Biff
Microsoft Excel MVP
>I am trying to use the averageifs function to determine the average
> temperature given a specific date. When referenceing the dates to useI am
[quoted text clipped - 22 lines]
> data is less than the reference (when treated as a serial number). No the
> dates/times are not listed as text.
T. Valko - 04 Feb 2008 22:33 GMT
Or, since you only have one criteria you could use:
=AVERAGEIF(Sheet1!$A$2:$A$849,"<"&M130,Sheet1!$B$2:$B$849)

Signature
Biff
Microsoft Excel MVP
> Try this:
>
[quoted text clipped - 29 lines]
>> the
>> dates/times are not listed as text.