The weather has been very wet, and I fear we're facing a Spring like last year. God, I hope not. But if we do, I have just the thing, a collect (prayer) from the old Universalist Gospel Liturgy (1861 edition). It is with the occasional collects, page 149, if you have a copy.
Raining. [suggested readings] Titus iii. 4-6. Mal. iii. 10.
Giver of all good, who art baptizing this house by the waters poured from the hollow of Thy hand: We praise Thee for the washing of regeneration richly shed upon us through Jesus Christ our Saviour; and humbly we pray for the renewing of the Holy Spirit, in the consecration from on high.
Thy faithfulness, O Lord, is above the clouds. Open Thou the windows of heaven, and pour upon us a blessing for which we shall find no room, that our souls may be filled with devotion to Thee, and overflow in peace and charity to all the world.