Season 14 EU:

What	When
Season 14 [EU] Signups Open	5th of November (20:00 CET)
Season 14 [EU] Signups Close	13th of December (23:59 CET)
Season 14 [EU] Seeding	14th of December
Season 14 [EU] Round 1 starts	4th of January
Season 14 [EU] Round 10 starts (last round)	8th of March
Last date to play regular season games	19th of March
Season 14 [EU] Draw Show	21st of March
Season 14 [EU] Playoff Group Stage starts	22nd of March
Season 14 [EU] Rare Cup Finals	10th of April
Season 14 [EU] Epic Cup Finals	11th of April
Season 14 [EU] Legendary Cup Finals	17th of April
Season 14 [EU] Mythic Championship Finals	18th of April
Season 14 [EU] Playoffs end	18th of April

Season 6 NA:

What	When
Season 6 [NA] Signups Open	6th of September
Season 6 [NA] Signups Close	25th of October
Season 6 [NA] Seeding	26th of October
Season 6 [NA] Round 1 starts	9th of November
Season 6 [NA] Round 8 starts (last round)	18th of January
Last date to play regular season games	29th of January
Season 6 [NA] Draw Show	31st of January
Season 6 [NA] Playoff Group Stage starts	1st of February
Season 6 [NA] Epic Cup Group Stage	1st of February - 19th of February
Season 6 [NA] Epic Cup Finals	21st of February
Season 6 [NA] Legendary and Mythic Group Stage	1st of February - 25th of February
Season 6 [NA] Legendary Cup Finals	27th of February
Season 6 [NA] Mythic Championship Finals	28th of February
Season 6 [NA] Playoff Ends	28th of February

Season 13 EU:

What	When
Season 13 [EU] Signups Open	5th of July (20:00 CEST)
Season 13 [EU] Signups Close	9th of August (23:59 CEST)
Season 13 [EU] Seeding	10th of August
Season 13 [EU] Round 1 starts	24th of August
Season 13 [EU] Round 10 starts (last round)	26th of October
Last date to play regular season games	6th of November
Season 13 [EU] Draw Show	8th of November
Season 13 [EU] Playoff Group Stage starts	9th of November
Season 13 [EU] Rare Cup Finals	28th of November
Season 13 [EU] Epic Cup Finals	29th of November
Season 13 [EU] Legendary Cup Finals	5th of December
Season 13 [EU] Mythic Championship Finals	6th of December
Season 13 [EU] Playoffs end	6th of December

Season 5 NA:

What	When
Season 5 [NA] Signups Open	19th of April
Season 5 [NA] Signups Close	21st of June
Season 5 [NA] Seeding	22nd of June
Season 5 [NA] Round 1 starts	6th of July
Season 5 [NA] Round 8 starts (last round)	24th of August
Last day to submit replays	4th of September
Season 5 [NA] Draw Show	6th of September
Season 5 [NA] Playoff Group Stage starts	7th of September
Season 5 [NA] Epic Cup Group Stage	7th of September - 1st of October
Season 5 [NA] Epic Cup Finals	4th of October
Season 5 [NA] Legendary and Mythic Group Stage	7th of September - 8th of October
Season 5 [NA] Legendary Cup Finals	10th of October
Season 5 [NA] Mythic Championship Finals	11th of October
Season 5 [NA] Playoff Ends	11th of October