Mass outbreak

In Generation II, if the player registered a certain Trainer in the Pokégear, that Trainer occasionally calls to tell the player that they saw or heard about a large number of Pokémon in a certain area. Until midnight (in-game time), the swarming Pokémon appear in the given area with much greater frequency than the usual 1%. Only one swarm can appear per day. The player can force a particular swarm to appear if a swarm has not already appeared that day by first deleting all possible phone numbers except the swarm Trainer's and then repeatedly toggling Daylight Savings Time by speaking with the player's Mom in New Bark Town. There is a 50% chance of triggering a phone call every time DST is changed.

In Generation III, in addition to making rare Pokémon temporarily more common, this feature can be combined with record mixing to allow the player to catch Pokémon that cannot be caught at all normally. Pokémon encountered through mass outbreaks will also have a predefined set of moves.

After entering the Hall of Fame, every time the player wins a battle, there is a ~0.5% (328/65536) chance that the game will generate an outbreak; this does not apply to link battles, e-Reader battles, the Safari Zone, or the Battle Tower/Frontier. After an outbreak is generated, the television program announcing it will appear the next day. Once the television program has been watched, the outbreak becomes active.[1] Outbreaks last until the end of the day after they became active, during which time the swarming Pokémon will have an appearance rate of 50%.

The record mixing feature of Pokémon Ruby, Sapphire, and Emerald allows players to give an outbreak they've seen to other players, regardless of whether that outbreak would naturally occur in the player's game. The traded outbreaks will be announced on television in the following days after mixing records.

Mass outbreaks were largely expanded in Generation IV. Once the player attains the National Pokédex and has entered the Hall of Fame, a "swarm of Pokémon" will appear every day in a particular location, 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 talking to Lucas/Dawn's sister or by watching the Sinnoh television ^DPPt, or by listening to Professor Oak's Pokémon Talk ^HGSS.

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

The species of an outbreak seems to be determined using a formula, because it is not chosen randomly when the player starts the game that day. Even if the date is edited, the next swarm will always be the same. 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.

Many of the Pokémon obtained through mass outbreaks are outside of the Sinnoh Pokédex, and are usually otherwise exclusive to other regions.

Due to the high encounter chances for Pokémon that appear during outbreaks, they make for longer and better chains when using the Poké Radar.

#	Pokémon		Location	Levels	Game
016		Pidgey	Route 229	51	D	P	Pt
081		Magnemite	Fuego Ironworks	28-29	D	P	Pt
083		Farfetch'd	Route 221	28, 29Pt	D	P	Pt
084		Doduo	Route 201	2	D	P	Pt
096		Drowzee	Route 215	19Pt, 20, 21DP	D	P	Pt
098		Krabby	Route 226	52	D	P	Pt
				48-49	D	P	Pt
100		Voltorb	Route 218	28, 29Pt	D	P	Pt
104		Cubone	Route 203	4	D	P	Pt
108		Lickitung	Lake Valor	34, 36	D	P	Pt
127		Pinsir	Route 229	48-49	D	P	Pt
177		Natu	Route 224	53	D	P	Pt
				50	D	P	Pt
206		Dunsparce	Route 208	16	D	P	Pt
				18	D	P	Pt
209		Snubbull	Route 209	16	D	P	Pt
				18-19	D	P	Pt
220		Swinub	Route 217	34	D	P	Pt
222		Corsola	Route 230	50	D	P	Pt
				48	D	P	Pt
225		Delibird	Route 216	32	D	P	Pt
			Route 217	32-33	D	P	Pt
231		Phanpy	Route 207	5, 7Pt	D	P	Pt
238		Smoochum	Lake Acuity	35	D	P	Pt
246		Larvitar	Route 206	16	D	P	Pt
263		Zigzagoon	Route 202	3	D	P	Pt
283		Surskit	Lake Verity	2	D	P	Pt
287		Slakoth	Eterna Forest	10, 11Pt	D	P	Pt
296		Makuhita	Route 225	50-51	D	P	Pt
				48-49	D	P	Pt
299		Nosepass	Route 206	14	D	P	Pt
300		Skitty	Route 222	39Pt, 40	D	P	Pt
309		Electrike	Valley Windworks	7	D	P	Pt
				9-10	D	P	Pt
325		Spoink	Route 214	21Pt, 22, 23DP	D	P	Pt
327		Spinda	Route 227	55	D	P	Pt
				53-54	D	P	Pt
359		Absol	Route 213	20	D	P	Pt
374		Beldum	Route 228	53	D	P	Pt
				51-52	D	P	Pt

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

#	Pokémon		Location	Levels	Game
113		Chansey	Route 13	23	HG	SS
132		Ditto	Route 47	34	HG	SS
183		Marill	Mt. Mortar	15	HG	SS
193		Yanma	Route 35	12	HG	SS
206		Dunsparce	Dark Cave	2-3	HG	SS
209		Snubbull	Route 38	16	HG	SS
211		Qwilfish	Route 32	40	HG	SS
223		Remoraid	Route 44	20	HG	SS
261		Poochyena	Route 1	2	HG	SS
278		Wingull	Vermilion City Surfing	35	HG	SS
280		Ralts	Route 34	10-11	HG	SS
302		Sableye	Route 9	13-15	HG	SS
303		Mawile	Route 9	13-15	HG	SS
316		Gulpin	Route 3	5	HG	SS
333		Swablu	Route 45	23	HG	SS
340		Whiscash	Violet City Fishing	10/20/40 Old/Good/Super Rod	HG	SS
343		Baltoy	Route 3	5	HG	SS
366		Clamperl	Route 19 Surfing	35	HG	SS
369		Relicanth	Route 12 Fishing	40 Super Rod	HG	SS
370		Luvdisc	Route 27 Surfing	20	HG	SS
401		Kricketot	Viridian Forest	3	HG	SS
427		Buneary	Route 25	8-10	HG	SS

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

Unlike in previous games, mass outbreaks can be manipulated by soft resetting the game, but only if the player has not saved their game at all that day. When the game is restarted, there will be a different Pokémon swarming.

During winter, the monitor may occasionally not report on outbreaks, which is due to parts of Route 8, where Croagunk can be found, becoming frozen during Winter and not allowing the Pokémon to be caught there. All outbreaks in these games have a level range of 15-55.

#	Pokémon		Location	Levels	Game
046		Paras	Route 11	15-55	B	W
056		Mankey	Route 15	15-55	B	W
083		Farfetch'd	Route 1	15-55	B	W
084		Doduo	Route 12	15-55	B	W
102		Exeggcute	Route 18	15-55	B	W
161		Sentret	Route 7	15-55	B	W
193		Yanma	Route 14	15-55	B	W
204		Pineco	Route 16	15-55	B	W
228		Houndour	Route 9	15-55	B	W
235		Smeargle	Route 5	15-55	B	W
236		Tyrogue	Route 10	15-55	B	W
261		Poochyena	Route 9	15-55	B	W
285		Shroomish	Route 11	15-55	B	W
311		Plusle	Route 6	15-55	B	W
312		Minun	Route 6	15-55	B	W
313		Volbeat	Route 3	15-55	B	W
314		Illumise	Route 3	15-55	B	W
353		Shuppet	Route 13	15-55	B	W
360		Wynaut	Route 2	15-55	B	W
449		Hippopotas	Route 4	15-55	B	W
453		Croagunk	Route 8	15-55	B	W

All outbreaks in these games have a level range of 40-55 and an encounter rate of 40%.

#	Pokémon		Location	Levels	Game
022		Fearow	Route 15	40-55	B2	W2
079		Slowpoke	Abundant Shrine	40-55	B2	W2
083		Farfetch'd	Route 1	40-55	B2	W2
084		Doduo	Route 12	40-55	B2	W2
097		Hypno	Dreamyard	40-55	B2	W2
122		Mr. Mime	Route 20	40-55	B2	W2
162		Furret	Route 7	40-55	B2	W2
166		Ledian	Route 22	40-55	B2	W2
168		Ariados	Route 22	40-55	B2	W2
177		Natu	Route 5	40-55	B2	W2
185		Sudowoodo	Route 20	40-55	B2	W2
187		Hoppip	Route 18	40-55	B2	W2
195		Quagsire	Route 8	40-55	B2	W2
204		Pineco	Route 16	40-55	B2	W2
277		Swellow	Route 13	40-55	B2	W2
284		Masquerain	Route 11	40-55	B2	W2
311		Plusle	Route 6	40-55	B2	W2
312		Minun	Route 6	40-55	B2	W2
313		Volbeat	Route 3	40-55	B2	W2
314		Illumise	Route 3	40-55	B2	W2
317		Swalot	Route 9	40-55	B2	W2
332		Cacturne	Reversal Mountain	40-55	B2	W2
450		Hippowdon	Desert Resort	40-55	B2	W2

Mass Outbreaks in Pokémon Legends: Arceus can be seen on the map when choosing where to travel. Choosing a location with an Outbreak will guarantee you the chance to take part in it. They will only have four Pokémon spawned at any given time until they run out. Typically, mass outbreaks will spawn anywhere from 10-15 Pokémon before they go away. Mass Outbreaks greatly increase shiny chances. Research Tasks help increase that Shiny Pokémon appearing in outbreaks.

The majority of Pokémon species in Hisui can have a Mass Outbreak in the region(s) where they normally spawn in the overworld, with the exception of five categories:

• Pokémon species that never appear in the overworld (Mythical and Legendary Pokémon, Sneasler, Overqwil, Hisuian Electrode, etc.);
• Pokémon species that appear exclusively as fixed Alphas in the overworld (such as Infernape, Torterra, Empoleon, Rapidash, Dusknoir, etc.);
• Pokémon species that appear exclusively in the Space-Time Distortions (starter lines, Eeveelutions, Magnemite line, Johtonian Sneasel line, Cranidos and Shieldon lines, etc.);
• Pokémon species that exclusively appear flying in the overworld (Togetic, Togekiss, Hisuian Braviary, Magnezone, Crobat).

Also, Pokémon that normally spawn only during the day or at night in the overworld can have an Outbreak at any time of day, such as Drifloon or Zubat that normally only spawn at nighttime, but can outbreak during the day as well.

Hisui Dex #	National Dex #	Pokémon		Possible outbreak location(s)					Levels
				Obsidian Fieldlands	Crimson Mirelands	Cobalt Coastlands	Coronet Highlands	Alabaster Icelands
010	399		Bidoof	✓	✓			✓	?
011	400		Bibarel	✓	✓	✓		✓	?
012	396		Starly	✓		✓			?
013	397		Staravia	✓		✓			?
014	398		Staraptor	✓		✓			?
015	403		Shinx	✓			✓		?
016	404		Luxio	✓			✓		?
017	405		Luxray	✓			✓		?
018	265		Wurmple	✓					?
019	266		Silcoon	✓					?
020	267		Beautifly	✓		✓			?
021	268		Cascoon	✓					?
022	269		Dustox	✓		✓			?
023	077		Ponyta	✓					?
025	133		Eevee	✓		✓		✓	?
034	041		Zubat	✓	✓		✓	✓	?
035	042		Golbat	✓	✓		✓	✓	?
037	425		Drifloon	✓		✓		✓	?
038	426		Drifblim	✓		✓		✓	?
039	401		Kricketot	✓	✓				?
040	402		Kricketune	✓	✓				?
041	418		Buizel	✓		✓			?
042	419		Floatzel	✓		✓			?
043	412		Burmy	✓	✓	✓	✓	✓	?
044	413		Wormadam	✓	✓	✓	✓	✓	?
045	414		Mothim	✓		✓	✓		?
046	074		Geodude	✓	✓	✓	✓		?
047	075		Graveler	✓	✓	✓	✓	✓	?
049	234		Stantler	✓		✓	✓	✓	?
051	446		Munchlax	✓				✓	?
052	143		Snorlax					✓	?
053	046		Paras	✓	✓	✓	✓		?
054	047		Parasect	✓	✓	✓	✓		?
055	172		Pichu	✓	✓				?
056	025		Pikachu	✓	✓	✓			?
058	063		Abra	✓				✓	?
059	064		Kadabra	✓				✓	?
061	390		Chimchar	✓					?
062	391		Monferno	✓					?
064	427		Buneary	✓				✓	?
065	428		Lopunny					✓	?
066	420		Cherubi	✓	✓		✓		?
067	421		Cherrim	✓	✓		✓		?
068	054		Psyduck	✓	✓	✓	✓		?
069	055		Golduck		✓	✓	✓		?
070	415		Combee	✓	✓	✓			?
071	416		Vespiquen		✓				?
072	123		Scyther	✓			✓		?
075	214		Heracross				✓		?
076	439		Mime Jr.	✓					?
077	122		Mr. Mime	✓					?
078	190		Aipom	✓		✓		✓	?
079	424		Ambipom			✓		✓	?
080	129		Magikarp	✓			✓		?
081	130		Gyarados	✓		✓	✓		?
082	422		Shellos	✓		✓			?
083	423		Gastrodon	✓		✓			?
084	211		Qwilfish	✓		✓			?
086	440		Happiny	✓		✓		✓	?
087	113		Chansey	✓		✓		✓	?
088	242		Blissey					✓	?
089	406		Budew		✓		✓		?
090	315		Roselia		✓		✓		?
092	455		Carnivine		✓		✓		?
093	548		Petilil		✓				?
095	114		Tangela		✓	✓			?
097	339		Barboach		✓		✓		?
098	340		Whiscash		✓		✓		?
099	453		Croagunk		✓		✓		?
100	454		Toxicroak		✓	✓	✓		?
101	280		Ralts		✓			✓	?
102	281		Kirlia		✓			✓	?
103	282		Gardevoir					✓	?
105	193		Yanma		✓		✓		?
106	469		Yanmega				✓		?
107	449		Hippopotas		✓		✓		?
108	450		Hippowdon		✓		✓		?
109	417		Pachirisu		✓				?
110	434		Stunky		✓		✓		?
111	435		Skuntank		✓		✓		?
112	216		Teddiursa		✓		✓		?
113	217		Ursaring		✓		✓		?
115	704		Goomy		✓		✓		?
116	705		Sliggoo		✓		✓		?
118	095		Onix		✓		✓		?
120	111		Rhyhorn		✓		✓		?
121	112		Rhydon				✓		?
123	438		Bonsly		✓		✓		?
124	185		Sudowoodo		✓		✓		?
125	108		Lickitung		✓			✓	?
126	463		Lickilicky					✓	?
127	175		Togepi		✓	✓			?
130	387		Turtwig		✓				?
131	388		Grotle		✓				?
136	092		Gastly		✓		✓	✓	?
137	093		Haunter		✓		✓	✓	?
140	198		Murkrow		✓	✓			?
143	363		Spheal			✓			?
144	364		Sealeo			✓			?
145	365		Walrein			✓			?
146	223		Remoraid			✓			?
147	224		Octillery			✓			?
148	451		Skorupi			✓			?
149	452		Drapion			✓			?
150	058		Growlithe			✓			?
152	431		Glameow			✓		✓	?
153	432		Purugly			✓		✓	?
154	066		Machop	✓		✓	✓	✓	?
155	067		Machoke	✓		✓	✓	✓	?
157	441		Chatot			✓			?
158	355		Duskull			✓		✓	?
159	356		Dusclops			✓		✓	?
161	393		Piplup			✓			?
162	394		Prinplup			✓			?
164	458		Mantyke			✓			?
165	226		Mantine			✓			?
166	550		Basculin			✓	✓	✓	?
168	037		Vulpix			✓			?
170	072		Tentacool			✓			?
171	073		Tentacruel			✓			?
172	456		Finneon			✓			?
173	457		Lumineon			✓			?
174	240		Magby			✓			?
175	126		Magmar			✓			?
180	436		Bronzor				✓	✓	?
181	437		Bronzong				✓	✓	?
182	239		Elekid				✓	✓	?
183	125		Electabuzz				✓	✓	?
185	207		Gligar				✓	✓	?
187	443		Gible				✓	✓	?
188	444		Gabite					✓	?
190	299		Nosepass				✓		?
192	100		Voltorb				✓		?
194	479		Rotom				✓		?
195	433		Chingling				✓	✓	?
196	358		Chimecho				✓	✓	?
197	200		Misdreavus				✓	✓	?
199	173		Cleffa				✓		?
200	035		Clefairy				✓		?
202	215		Sneasel				✓	✓	?
205	361		Snorunt					✓	?
206	362		Glalie					✓	?
207	478		Froslass					✓	?
212	220		Swinub					✓	?
213	221		Piloswine					✓	?
215	712		Bergmite					✓	?
216	713		Avalugg					✓	?
217	459		Snover					✓	?
218	460		Abomasnow					✓	?
219	570		Zorua					✓	?
220	571		Zoroark					✓	?
221	627		Rufflet					✓	?
223	447		Riolu					✓	?