The Wednesday Office hymns, "from the Оctave of the Epiphany until the 1st Sunday in Lent"

From Hymn melodies for the whole year from the Sarum Service books, for Wednesdays in Epiphanytide the hymns are as follows:

From the Оctave of the Epiphany until the 1st Sunday in Lent - On Wednesdays:

Mattins: Rerum Creator optime... ... ... 15
Lauds: Nox et tenebre et nubila... ... ... 17
Evensong: Celi Deus sanctissime ... ... ... 20

There are in total 21 hymns for this season:  3 different hymns per day, for each day of the week.  Each day's hymns for this period, including texts and audio files, are available at the following links:

• Sunday
• Monday
• Tuesday
• Wednesday
• Thursday
• Friday
• Saturday

The Wednesday hymn for Mattins during this period is Rerum Creator optime; Hymn melodies prescribes it to be sung to melody #15:

The Liber Hymnarius has a version of this in Latin, sung to melody #15; click the arrow to listen to the mp3:

Rerum creator optime (saec. VI?)
Meter: 8.8.8.8
Melody: d e f g eg f e f
  H.IV, p. 198

TPL says this about the hymn:

Attributed to Pope St. Gregory the Great (540-604). This traditional Matins hymn is used in the Liturgia Horarum for the Office of the Readings for Wednesdays of the 1st and 3rd weeks of the Psalter during Ordinary Time. Likewise it is found as the Matins hymn for Wednesdays in the Roman Breviary.

Here are the words in Latin and English; the translation is by John Henry Newman (1801-1890).

RERUM Creator optime, rectorque noster, respice; nos a quiete noxia mersos sopore libera.	WHO madest all and dost control, Lord, with Thy touch divine, cast out the slumbers of the soul, the rest that in not Thine.
Te, sancte Christe, poscimus; ignosce tu criminibus,1 ad confitendum surgimus morasque noctis rumpimus.	Look down, Eternal Holiness, and wash the sins away, of those, who, rising to confess, outstrip the lingering day.
Mentes manusque tollimus, Propheta sicut noctibus nobis gerendum praecipit Paulusque gestis censuit.	Our hearts and hands by night, O Lord, we lift them in our need; as holy Psalmists give the word, and holy Paul the deed.
Vides malum quod gessimus;2 occulta nostra pandimus, preces gementes fundimus; dimitte quod peccavimus.	Each sin to Thee of years gone by, each hidden stain lies bare; we shrink not from Thine awful eye, but pray that Thou wouldst spare.
Sit, Christe rex piissime, tibi Patrique gloria cum Spiritu Paraclito, in sempiterna saecula. Amen.	Grant this, O Father, Only Son and Spirit, God of grace, to whom all worship shall be done in every time and place. Amen.

At Wednesday Lauds during this period, the prescribed hymn is Nox et tenebre et nubila, sung, according to Hymn melodies,  to melody #17:

LLPB offers this mp3 (in English) of Nox et tenebre et nubila sung to melody #17; they call it "Ye Clouds and Darkness."

Here's TPL on this hymn:

This hymn is a cento from the Morning Hymn of the Cathemerinon of Prudentius (384-413). It is a traditional hymn for Lauds and is the hymn for Lauds for Wednesday for the 1st and 3rd weeks of the Psalter during Ordinary Time. Likewise it is found as the hymn for Wednesday Lauds in the Roman Breviary.

Here are the words in Latin and English; the translation - this is the set of words on the audio file, not the ones at TPL - is anonymous: 

NOX et tenebrae et nubila, confusa mundi et turbida, lux intrat, albescit polus: Christus venit; discedite.	YE clouds and darkness, hosts of night, That breed confusion and affright, Begone! o’erhead the dawn shines clear, The light breaks in, and Christ is here.
Caligo terrae scinditur percussa solis spiculo, rebusque iam color redit vultu nitentis sideris.	Earth’s gloom flees broken and dispersed, By the sun’s piercing shafts coerced: The day-star’s eyes rain influence bright, And colors glimmer back to sight.
Sic nostra mox obscuritas fraudisque pectus conscium, ruptis retectum nubibus, regnante pallescet Deo.	-
Te, Christe, solum novimus, te mente pura et simplici rogare curvato genu flendo et canendo discimus.1	Thee, Christ, alone we know; to Thee We bend in pure simplicity; Our songs with tears to Thee arise; Prove Thou our hearts with Thy clear eyes.
Intende nostris sensibus vitamque totam dispice: sunt multa fucis illita quae luce purgentur tua.2	Though we be stained with blots within, Thy quickening rays shall purge our sin; Light of the Morning Star, Thy grace Shed on us from Thy cloudless face.
Sit, Christe, rex piissime, tibi Patrique gloria cum Spiritu Paraclito, in sempiterna saecula. Amen.	All laud to God the Father be, All praise, eternal Son, to Thee; All glory, as is ever meet, To God the holy Paraclete.

At Wednesday Vespers, the hymn prescribed by Hymn melodies during this period is Celi Deus sanctissime, sung to melody #20:

LLPB offers this mp3 (in English) of Celi Deus sanctissime sung to this tune; they call it  "Most Holy Lord and God of Heaven."

One really interesting thing about the daily Vespers hymns is that they recapitulate the 7 days of Creation!  For instance,  TPL says this about Celi Deus sanctissime:

Attributed to Pope St. Gregory the Great (540-604). This hymn continues with the theme of Creation present in the Vespers Hymns for Monday and Tuesday. Here the work of the fourth day, the creation of the heavenly bodies in the firmament, is chronicled (Gen 1, 14-19). This hymn is traditionally sung at Wednesday Vespers and is used in the Liturgia Horarum at Vespers for Wednesdays of the first and third weeks of the Psalter during Ordinary Time. Likewise the hymn is also found in the Roman Breviary for Wednesday Vespers.

Here are the words in Latin and English; the translation - again, this is the set of words on the audio file, not the ones at TPL - is by Maurice Frederick Bell, 1906.

CAELI Deus sanctissime, qui lucidum centrum poli1 candore pingis igneo augens decori2 lumine.	MOST HOLY Lord and God of heaven, who to the glowing sky hast given the fires that in the east are born with gradual splendors of the morn;:
Quarto die qui flammeam solis rotam constituens, lunae ministras ordini, vagos recursus siderum,3	Who, on the fourth day, didst reveal the sun's enkindled flaming wheel, didst set the moon her ordered ways, and stars their ever-winding maze;
Ut noctibus, vel lumini diremptionis terminum, primordiis et mensium signum dares notissimum:	That each in its appointed way might separate the night from day, and of the seasons through the year the well-remembered signs declare:
Illumina cor hominum,4 absterge sordes mentium, resolve culpae vinculum, everte moles criminum.	Illuminate our hearts within, and cleanse our minds from stain of sin; unburdened of our guilty load may we unfettered serve our God.
Praesta, Pater piissime, Patrique compar Unice, cum Spiritu Paraclito regnans per omne saeculum.	O Father, that we ask be done, through Jesus Christ, thine only Son; who, with the Holy Ghost and thee, doth live and reign eternally.