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, are a feature introduced in Generation II that allows the player to catch Pokémon that are usually rare or otherwise unobtainable.

Generation II

Mass Outbreaks originated in Generation II. Once the phone numbers of certain Trainers are registered in the player's Pokégear, those Trainers will occassionally call to tell the player thay they saw or heard about a large number of Pokémon in a certain area; for the next 30 minutes after such a call (in real time, not play time), the swarming Pokémon will appear much more frequently in the given area.

Pokémon Gold and Silver

Pokémon		Location	Notifier
	Marill	Mt. Mortar	Hiker Parry
	Yanma	Route 35	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 allows the player to catch Pokémon that cannot be caught normally and make rare Pokémon temporarily more common. This was possible due to the record mixing feature of Pokémon Ruby and Sapphire. The outbreaks are advised by televisions in houses, where the Pokémon and its location is told.

Pokémon Ruby, Sapphire, and Emerald

Pokémon		Location	Level	Game
	Lotad	Route 114*	13	R		S		E
	Seedot	Route 117*	13	R		S		E
	Surskit	Routes 102 and 114*	15	R		S		E
	Skitty	Route 116	15	R		S		E

Generation IV

Mass Outbreaks were largely expanded in Generation IV. Once the player attains the National Pokédex, every day in a particular location, a "swarm of Pokémon" appears, which changes the probability of finding the given Pokémon from 0% to 40%. Outbreaks last only one day and are random events. Information about Mass Outbreaks can be found in Sandgem Town, by watching Sinnoh television, or by listening to Professor Oak's Pokémon Talk.

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

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.

Pokémon Diamond, Pearl, and Platinum

By also using the Poké Radar and Dual-slot mode in Pokémon Diamond and Pearl, players can get all Pokémon excluding Tangela, Tropius, the starter Pokémon, and legendary Pokémon 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 Pokédex, and are usually exclusive to other regions. 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 in Diamond, Pearl, and Platinum.

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

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	49–52	D		P		Pt
	Voltorb	Route 218	28, 29	D		P		Pt
	Cubone	Route 203	4	D		P		Pt
		Route 202	3,4	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	18	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	10,11	D		P		Pt
	Makuhita	Route 225	48-51	D		P		Pt
	Nosepass	Route 206	14	D		P		Pt
	Skitty	Route 222	40	D		P		Pt
			36-40	D		P		Pt
	Electrike	Valley Windworks	7,9,10	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	51-54	D		P		Pt

Pokémon HeartGold and SoulSilver

The feature also appears in HeartGold and SoulSilver, where all the wild Pokémon available include all those that were available in Generation II, Ditto, Chansey, and Pokémon from Hoenn and Sinnoh. Information or swarms can now be found by listening to Professor Oak's Pokémon Talk on the Pokégear radio.

Pokémon		Location	Levels	Game
	Chansey	Route 13	23	HG			SS
	Ditto	Route 47	34	HG			SS
	Marill	Mt. Mortar	15	HG			SS
	Yanma	Route 35	12	HG			SS
	Dunsparce	Dark Cave	2-3	HG			SS
	Snubbull	Route 38	16	HG			SS
	Qwilfish	Route 32	40	HG			SS
	Remoraid	Route 44	20	HG			SS
	Poochyena	Route 1	2	HG			SS
	Wingull	Vermilion City*	35	HG			SS
	Ralts	Route 34	10-11	HG			SS
	Sableye	Route 9	13-15	HG			SS
	Mawile	Route 9	13-15	HG			SS
	Gulpin	Route 3	5	HG			SS
	Swablu	Route 45	23	HG			SS
	Whiscash	Violet City	40	HG			SS
	Baltoy	Route 3	5	HG			SS
	Clamperl	Route 19	35	HG			SS
	Relicanth	Route 12*	40	HG			SS
	Luvdisc	Route 27*	20	HG			SS
	Kricketot	Viridian Forest	3	HG			SS
	Buneary	Route 25	8-10	HG			SS

Generation V

Black and White

The lookout stations in Unova have a monitor inside that will alert the player where an outbreak is taking place.

Pokémon		Location	Levels	Game
	Paras	Route 11	?	B			W
	Mankey	Route 15	?	B			W
	Farfetch'd	Route 1	?	B			W
	Doduo	Route 12	?	B			W
	Exeggcute	Route 18	?	B			W
	Sentret	Route 7	?	B			W
	Yanma	Route 14	?	B			W
	Pineco	Route 16	?	B			W
	Houndour	Route 9	?	B			W
	Smeargle	Route 5	?	B			W
	Tyrogue	Route 10	?	B			W
	Poochyena	Route 9	?	B			W
	Shroomish	Route 11	?	B			W
	Plusle	Route 6	?	B			W
	Minun	Route 6	?	B			W
	Volbeat	Route 3	?	B			W
	Illumise	Route 3	?	B			W
	Shuppet	Route 13	?	B			W
	Wynaut	Route 2	?	B			W
	Hippopotas	Route 4	?	B			W
	Croagunk	Route 8	?	B			W

See also

• Dual-slot mode
• Poké Radar