This poem is from Aígidecht Aithirni, or ‘The Guesting of Athirne.’ Athirne was a satirist and poet of the Ulaid, who, in this tale, went to stay with his foster-son for a night but got delayed each time he attempted to leave. The tale is preserved in three different manuscripts, and are of varying lengths and detail. Four of the poems detail the good things about a particular season.
Fó sín smarad síthaister,
sám fid forard dorglide
nach fet gaíthe glúaiss;
Glass clúm caille clithaige,
cerba srotha saebuisci,
sén i fótán fó.
Summer is a fine season for long journeys,
Calm is the high, choice wood
that no breath of wind stirs.
Green is the plumage of the sheltering wood,
streams of wandering water are dried up,
there is a good omen in the fine turf.
From A Golden Treasury of Irish Poetry A.D. 600 to 1200, edited and translated by David Greene and Frank O’Connor, pp142-143.