Our Valentine's Day Traditional Post

And here's a grammatical tip for the day:

There are only three important points you need to remember:

Capitalize both the V and the D in 'Valentine's Day'.

Make sure you include a possessive apostrophe in 'Valentine's Day'. The day is named for Saint Valentine, so it 'belongs' to him. (Check our guide to apostrophe usage if you're not sure why this matters.) Modern usage generally drops the 'Saint' or 'St.' prefix, though you can throw it in if you like.

The noun 'valentine' (describing the card you send or the individual you're pursuing) doesn't have a capital. So you can ask "Did you get my valentine?" or "Did you get my Valentine's Day card?"
Accuracy isn't always sexy, but it matters.

Source: https://www.lifehacker.com.au/2013/02/how-to-spell-valentines-day-correctly/