"It is ten minutes past two."

Translation: Mae hi'n ddeg munud wedi dau.

[Jb11131999]

So mae'n and mae hi'n both can be used for time?

[Mwsogl]

Mae'n is the squished form of Mae hi'n.

[NoelGoetowski]

I believe it's pronounced squeeshed.

[djzeus01]

"ddeng?"

[mizinamo]

Gareth King says in Modern Welsh: A Comprehensive Grammar:

Deg has an alternative form deng which generally appears before
time-words beginning with m-: deng munud ten minutes, deng mis
ten months, deng nmlynedd (NM of blynedd) ten years; and by the
same token in the numerals deng mil ten thousand and deng miliwn
ten million. Note also deng ⁿniwrnod (NM of diwrnod) ten days, deng
milltir ten miles and deng modfedd ten inches. In most other cases,
deg o° is the preferred construction – deg o °fapiau ten maps.

(ⁿ and ° indicate mutations.)

[JohnReid8]

From what I can tell, it's used before vowels, but not before consonants.

But it is possible that I'm not reading Wiktionary right on this one.

[StephenDunscombe]

It's a weird form that only shows up in certain sentences, and I can't for the life of me remember what the rule is.