Mass outbreak

My Pokémon Ranch explains the general mechanics of a Mass Outbreak.

Mass Outbreaks (Japanese: 大量発生 mass outbreak), also known as swarms, is a feature that allows the player to catch Pokémon that are usually rare in their games. Mass Outbreaks became available starting in Generation II.

Generation II

Mass Outbreaks originated in Generation II. The player could register certain trainers with the phone feature of the PokéGear, in which they would occasionally call the player to give advice of a Pokémon outbreak and its location.

Pokémon		Area	Notifier
	Marill	Mt. Mortar	Hiker Parry
	Yanma	Route 36	Bug Catcher Arnie
	Dunsparce	Dark Cave	Hiker Anthony
	Snubbull	Route 38	Schoolboy Chad
	Qwilfish	Route 32*	Fisherman Ralph
	Remoraid	Route 44*	Fisherman Wilton

Generation III

In Generation III this method allowed the player to catch Pokémon that would not be caught normally. This was possible due to the Record Mixing feature of Pokémon Ruby and Sapphire. The outbreaks were advised by televisions in houses, where the Pokémon and its location was told.

Pokémon		Area
	Lotad	Route 114*
	Seedot	Route 117*
	Surskit	Routes 102 and 114
	Skitty	Route 116

Generation IV

Mass Outbreaks were largely expanded in Generation IV. By also using the Poké Radar and Dual-slot mode in Pokémon Diamond and Pearl, players can get all Pokémon excluding Tangela, Tropius, the starters, and legendaries of previous generations, while Tangela, Tropius and two Legendary Trios can be regularly acquired in Pokémon Platinum.

Many of the Pokémon obtained through Mass Outbreaks are outside of the Sinnoh Dex, and are usually exclusive to other regions. Once the player attains the National Pokédex, every day in a particular location, a "swarm of Pokémon" appears. By this term it is meant that the probability of finding the given Pokémon grows from 0% to 40%, making this very easy. Outbreaks last only one day and are random events. However, the player can obtain information about the current outbreak by talking to, depending on their own gender, Dawn's or Lucas's sister in Sandgem Town, or seeing the news report on a TV.

Due to higher catching rates for Pokémon that appear during outbreaks, they make longer and better chains when using Poké Radar.

The species of an outbreaks seems to be determined using a formula, because it is not chosen randomly when the player starts the game that day. It is also possible that the species is determined the day before, though there is no additional evidence to support this. If the DS clock is changed or a different DS is used, then the game will detect this and will not change the species swarming until 12:00 AM.

When players all join the same group, they will all experience the same outbreak on any given day.

Pokémon		Location	Levels	Game
	Pidgey	Route 229	51	D	P	Pt
	Magnemite	Fuego Ironworks	28, 29	D	P	Pt
	Farfetch'd	Route 221	28	D	P	Pt
	Doduo	Route 201	2	D	P	Pt
	Drowzee	Route 215	20, 21	D	P	Pt
	Krabby	Route 226	52	D	P	Pt
	Voltorb	Route 218	28	D	P	Pt
	Cubone	Route 203	4	D	P	Pt
		Route 202	3	D	P	Pt
	Lickitung	Lake Valor	34–36	D	P	Pt
	Pinsir	Route 229	48, 49	D	P	Pt
	Natu	Route 224	53	D	P	Pt
	Dunsparce	Route 208	16	D	P	Pt
	Snubbull	Route 209	16	D	P	Pt
	Swinub	Route 217	34	D	P	Pt
	Corsola	Route 230	50	D	P	Pt
	Delibird	Route 216	32	D	P	Pt
		Route 217	32, 33	D	P	Pt
	Phanpy	Route 207	5	D	P	Pt
	Smoochum	Lake Acuity	35	D	P	Pt
	Larvitar	Route 206	14–16	D	P	Pt
	Zigzagoon	Route 202	3	D	P	Pt
		Route 201	3	D	P	Pt
	Surskit	Lake Verity	2	D	P	Pt
	Slakoth	Eterna Forest	10	D	P	Pt
	Makuhita	Route 225	50, 51	D	P	Pt
	Nosepass	Route 206	14	D	P	Pt
	Skitty	Route 222	40	D	P	Pt
	Electrike	Valley Windworks	7	D	P	Pt
	Spoink	Route 214	22, 23	D	P	Pt
	Spinda	Route 227	55	D	P	Pt
	Absol	Route 213	20	D	P	Pt
	Beldum	Route 228	53, 54	D	P	Pt

See also

• Dual-slot mode
• Poké Radar