Try this out, with a few different time zones, time picker set to a few days or so.

search.spl

| gentimes increment=1s 
    [ makeresults 
    | addinfo 
    | rename info_max_time -> end info_min_time -> start 
    | fields start end 
    | convert timeformat="%m/%d/%y:%H:%M:%S" ctime(*) as * 
    | format "" "" "" "" "" ""] 
| rename starttime -> _time 
| fields 
| bin span=1h _time as hourly 
| eval evalhourly=round(relative_time(_time,"@h")) 
| bin span=12h _time as twelvehour 
| bin span=24h _time as twentyfourhour 
| eval evaldaily=round(relative_time(_time,"@d")) 
| bin span=1d _time as daily 
| convert ctime(*) as *_human 
| stats values(*) as *