Wednesday 1st August (or 19th July according to other sources) marks the Ancient Egyptian New year, traditionally marked the start of the Nile flood, started by the tears of Aset (Isis) over the death of Asar (Osirus). The exact correlation of the Egyptian New year to the modern calendar is disputed, but I favour the linking with the heliacal rising of Sirius (dawn visibility of Sirius) as this star, known to the Egyptians as Sopdet (pronounced Soppday) was closely associated with Aset.
In the Northern Hemisphere, this is also the Pagan Celebration of Lunasa, this is the start of the harvest, season of pregnancy, ripening, transformation and peace. This marks the height of the northern summer, when the Earth is most alive. Spellings vary for this Celtic/Gaelic Festival, which can be called Lughnasadh or Lúnasa (this latter 'Irish' spelling ironically appears closest to what most English-speakers would regard as the phonetic pronunciation — luu-na-sa), see atriptoireland.com for more on this. It is certainly the great festival of Lugh, or Lug, the great Celtic Sun King [Egyptian origins spring to mind here] and God of Light, with August is Lugh's sacred month. As someone interested in etymology (the study of words) I am thinking that surely the word 'light' (especially with the peculiar silent 'gh' which came to be identified with a host of other rhyming words in English such as sight and fright) comes from 'lugh'?
According to Celticdruidtemple.com, Lughnasa translates as "the games of Lugh" (pronounced as Lou or sometimes Luff) and alludes to the assembly for games coinciding with the first of three harvests. The month of August is apparently called Lughnasadh in Gaelic and it marks the last day of summer. This was a specifically Gaelic holiday and many of the other Celtic cultures also celebrate an autumn festival known by a range of names. As Beltaine on 1st May marks the start of summer - Lughnasa marks the end of summer. Lughnasa is historically linked with Lugh, a leading Celtic deity and hero. These games with a bull sacrifice and major feast [with interesting echoes of the Egyptian Bull cult where Ausar (Osirus) was portrayed as a bull-headed deity), which I believe led to the unfortunate Mediterranean Bull Fighting tradition], and for some it was the start of a trial marriage.
In some Wiccan and modern Pagan traditions, this festival for honouring Lugh is known as Lammas (see thoughtco.com). Allegedly, the word Lammas derives from an Old English phrase hlaf-maesse, translating as loaf mass. Lammas was an annual ritual, recogniing a community's dependency on what Thomas Hardy referred to as 'the ancient pulse of germ and birth.'"