Which is correct
"In Jan 2009" or "On Jan 2009"
During is the meaing, and during is better form (to me). Nothwithstanding that,
http://dictionary.cambridge.org/define.asp?key=39634&dict=CALD
"on" is improper unless it is specific.
http://dictionary.cambridge.org/define.asp?key=55337&dict=CALD
Bob Pursley is right.
Use "in" when you are referring to anytime during a particular month or year.
In January 1960, she had her 17th birthday.
In 1997, the school gained several grants for partnership academies.
Use "on" when you are referring to a particular day/date in a month and/or year.
On September 4, 1992, my first grandchild was born.
A powerful typhoon hit Taiwan on July 28, 2008.
The correct phrase is "In Jan 2009."
When indicating a specific month and year, we generally use the preposition "in" to show that something happened within that timeframe. So, we say "in January 2009" to convey that an event occurred during that month.
On the other hand, we use the preposition "on" when referring to specific days or dates. For example, we say "on January 1, 2009" to indicate a particular day within the month of January.
To summarize:
- Use "in" with months to show an event happening within a month (e.g., "in January 2009").
- Use "on" with specific dates to refer to a particular day within a month (e.g., "on January 1, 2009").