Source: Matt Molloy and Sean Keane - "Contentment Is Wealth" 
There is a lovely version of this at Brother Steve’s tinwhistle pages. Played by Tommy McCarthy and called "The First Month of Summer".
Does anyone have a transcription for the version of this played by Daimh and At First Light. It is quite different having been changed to the key of C so it would fit on the pipes!!
The version on Tripswitch:
T:The First Month of Spring
N:setting from ‘Tripswitch’ by Donal O’Connor & John McSherry
cAfA G2EG | G2EG cded | cA3 GE3 | [1 GA B/c/d efed :| [2 GA B/c/d e3d ||
c3e geae | geeg a3g | geeg a2ge | eddc defa |
ge3 geae | geeg a3g | efa2 ageg | fdec dfed ||
The First Day Of Spring https://thesession.org/tunes/4475 has more spring in it!
You’ll find it in CRÉV in A (ok for boxes and fiddles) and in Trip to Sligo in D (ok for flutes!)
And, after all that, myself and a few friends play it in G - how low can you get? 8)
The First Month Of Spring, X:4
The last tune in the set ‘C tune’ on the Daimh album The Pirates of Puirt.