averageifs help!

Hi all.
Working with Excel 2010. Attached spreadsheet to this post.

• Wind Data Tab
  This tab is filled with readings of wind speeds. I am only concerned with Date (column A) and Wind Data (int) (Column H). No additional calculations in this tab.
  
• Calculation Tab (conveniently named )
  I am trying to automate the ability for someone to enter a date period and have the average wind speed displayed. There are three areas. One where they can enter just a period, any period; One that produces the "weekly average"; finally one for all daily wind speed averages.
  
• I've left my attempt to use =averageifs in J3. =AVERAGEIFS('Wind Data'!$H$2:$H$16000;'Wind Data'!A2:A16000;">="&H3;'Wind Data'!A2:A16000;"<="&I3)... but obviously this isn't correct.
  - I'm guessing that the same formula can be entered into each of the cells Highlighted yellow (i.e. in each category - date range, week range, day range), but that might not be right either...

There's a lot more formatting etc. to do in the Calculation tab, but i'm stuck here at this formula. anything you guys can do to help will be greatly appreciated!!!

wind speed analysis.xlsx

I've never been so happy to have someone break wind in my general direction!
Thanks again.

It was my treat.

one final question...
what does the & sign do in this equation?
=AVERAGEIFS('Wind Data'!H2:H16000,'Wind Data'!A2:A16000,">="&Calculations!B3,'Wind Data'!A2:A16000,"<="&C3)

just so i understand, nothing urgent.

thanks again!

It's a concatenation symbol. It means "and" and is used for combining things and designates that the items before and after are separate.

A1 = pretty
B1 = pink
C1 = unicorns

D1 = A1B1C1 = A1B1C1 - This is no good!
D1 = A1&B1&C1 = prettypinkunicorns - Hurray!

Without & Excel thinks you're just referring to text or a named range.

young grasshopper learn much today

Very much appreciated.