Query date field
Gets all pages created until today
Add-PSSnapin microsoft.sharepoint.powershell -ea 0
$webUrl = "https://yourSitecollection"
$listName = "Pages"
$web = Get-SPWeb $webUrl
$list = $web.Lists[$listName]
$value = [DateTime]::Today
$date = Get-Date $value -Format "yyyy-MM-ddTHH:mm:ssZ"
#SPUtility.CreateISO8601DateTimeFromSystemDateTime method to achieve the same.
$query = new-object microsoft.sharepoint.spquery;
$query.Query = "<Where><Leq><FieldRef Name='Created'/><Value Type='DateTime'>"+ $date +"</Value></Leq></Where>";
$items = $list.GetItems($query)
$items.Count
Or you can query date directly, compared to today's date
<Where>
<Geq>
<FieldRef Name="MyDateColumn" />
<Value Type="DateTime">
<Today OffsetDays="-5" />
</Value>
</Geq>
</Where>
In case of need to include time, extend Value tag
<Value Type='DateTime' IncludeTimeValue='True'></Value>