Walk into any park in Pokémon GO and you’ll see the same few species appearing over and over. Change the weather, and the whole map shifts. Come back two weeks later, and the Machop that dominated last visit has been replaced entirely by Ralts. None of this is random — and once you understand why, you can put yourself in the right place at the right time, every time.
Pokémon GO uses a four-layer spawn system: fixed spawn points on the map, biomes that determine which species appear at each point, nests that temporarily focus a location on one species, and weather that boosts the frequency and quality of type-matching encounters. These systems were redesigned significantly when Niantic launched a formal Biomes feature on Earth Day 2024, tying real-world geography more directly to your map than ever before.
This guide breaks down each layer of the spawn system as it works in 2026, then shows you how to use them together to find more of the Pokémon you actually want.
Verified against April 2026 game build. Specific values may change following Niantic server updates.
Quick Start: What To Do Before You Read the Rest
If you want to skip straight to action, here’s the checklist. The sections below explain why each step works.
- Look for parks on your map — nests almost always appear in green spaces
- Check today’s in-game weather — identify which two or three types are boosted
- Prioritize catches that match current weather (better IVs, bonus Stardust)
- Find active nests via community Discord or The Silph Road before making a trip
- Walk while using Incense — moving cuts the spawn interval from 5 minutes to 1 minute
- Stack Incense + Lure at a busy PokéStop for maximum spawn density
- Note the exact minute a rare Pokémon appeared — that spawn point repeats at the same minute each hour
- Mark Thursdays at midnight UTC in your calendar — that’s when nests rotate worldwide
What Is the Pokémon GO Spawn System?
Every wild encounter starts with a spawn point — a fixed location on the map where the game server places Pokémon at regular intervals. But the spawn point only determines where Pokémon can appear. What actually shows up there depends on three additional layers stacked on top of it.
Think of it as a filtering system:
- Spawn point — can a Pokémon appear at this location at all?
- Biome — which species pool does this point pull from?
- Nest — has a nest override collapsed that pool to one species?
- Weather — are any types getting boosted frequency and quality right now?
These layers don’t replace each other — they stack. A Forest biome spawn point inside a Magikarp nest, during rainy weather, will produce almost exclusively Magikarp at higher levels than normal. Remove the nest, and you get the full Forest pool with Water/Bug types bumped up by rain. Remove the weather, and you’re back to the base Forest distribution.
How Spawn Points Work
Spawn points are fixed positions placed by Niantic using the S2 geometry library — a system that divides Earth’s surface into a hierarchical grid of cells. Pokémon GO uses Level 20 S2 cells (roughly 17m × 17m each) as the smallest unit for spawn point placement. The coverage of those cells is determined by OpenStreetMap data — if the terrain at a cell location has sufficient OSM mapping, it can host a spawn point.
The practical implication: urban areas generate more spawn points than rural ones. A city center with detailed road, building, and park data in OSM produces far more eligible L20 cells than a sparsely-mapped rural road. This is why walking through a city park gives you dozens of active spawns while the same distance in a remote area might produce none.
Each spawn point activates on a fixed schedule. Most spawn windows run for 15, 30, 45, or 60 minutes — the server assigns the duration, and the Pokémon despawns when it expires. The timing is consistent: if a spawn point fired at 3:15 PM, it will fire again at 4:15 PM. Players who track specific high-value spawn points often note what minute they appeared in order to predict the next window.
Biomes: How Your Real-World Location Shapes Encounters
Before April 2024, Pokémon GO used a loose “pots” system that roughly mapped terrain types to species pools. On Earth Day 2024, Niantic replaced this with four named biomes tied directly to OpenStreetMap terrain classifications. Your location’s biome determines which species pool your local spawn points draw from.
The four biomes and their representative spawns:
| Biome | Real-World Setting | Common Spawns | Notable Exclusive |
|---|---|---|---|
| Forest | Wooded parks, tree-covered areas | Bulbasaur, Caterpie, Weedle, Oddish | — |
| Beach | Coastal areas, shorelines, harbors | Magikarp, Psyduck, Seel, Squirtle | Wiglett (Beach only) |
| Mountain | Elevated terrain, rocky or highland areas | Sandshrew, Clefairy, Zubat, Diglett | — |
| City | Urban built-up zones, commercial areas | Pidgey, Machop, Gastly, Caterpie | — |
Biome boundaries aren’t drawn by Niantic manually — they inherit OSM tags. A park labeled “forest” in OSM maps to the Forest biome; a beach-tagged shoreline becomes the Beach biome. This means biomes in your city can be checked using third-party tools that visualize the OSM-based biome overlay.
The most consequential biome fact for completionists: Wiglett can only be found in Beach biomes. It was confirmed during the “Rediscover Kanto” event that certain species are biome-locked, making geographic awareness directly relevant to your Pokédex progress.
Nests: The Biome Override That Resets Every Two Weeks
A nest is a real-world location — almost always a park or nature reserve — where one specific Pokémon species spawns far more frequently than normal. When a nest is active, that species can account for 80–90% of all spawns in the area, temporarily overriding whatever the biome pool would normally produce.
How the Rotation Works
Nests operate on a strict global schedule: every 14 days, on Thursdays at 00:00 UTC, every nest worldwide switches to a new species. The replacement is random — there’s no pattern or cycle connecting one migration to the next. A Ralts nest has an equal chance of becoming Machop, Gastly, or anything else in the nestable pool.
Two types of migrations happen:
- Standard migration: The automatic Thursday rotation. Species is randomly reassigned globally.
- Forced migration: When an in-game event removes a species from the spawn pool (for example, a Bulbasaur event that pulls wild Bulbasaur into the event’s exclusive pool), any nest containing that species can’t function normally. The system shifts the nest’s Pokédex index up or down by one position. This is why you might see a Bulbasaur nest become Ivysaur mid-event — not because the nest migrated, but because the species it was pointing to became unavailable.
Which Pokémon Can Nest?
Not every species is nest-eligible. The following are excluded: regional exclusives (Tauros, Farfetch’d, Kangaskhan, etc.), most fully evolved Pokémon, species that hatch from 10km eggs, and several other species based on Niantic’s internal criteria. Roughly 130+ unevolved species across Generations 1–5 are confirmed nestable — the majority of the common wild pool.
How to Identify a Nest
The game gives no in-game indicator that a location is a nest. You identify one by observation: if one species accounts for 4 out of every 5 spawns in a park, it’s a nest. Community tracking sites (The Silph Road nest atlas, regional Discord servers) maintain near-real-time nest records submitted by players after each migration. Visiting these resources before a trip saves the trial-and-error of walking a park blind.
Nests are the primary reason serious players make dedicated trips to specific parks. Nest-farming — repeatedly catching the same species in a concentrated area — is the most efficient way to build candy for rare unevolved Pokémon that rarely appear in the normal wild pool.
Weather Boosts: The Spawn Multiplier Most Players Ignore
Weather is the most impactful real-time modifier to the spawn system. The game reads your device’s local conditions and applies a type boost that affects spawn frequency, encounter level, IVs, Stardust rewards, and combat damage simultaneously.
Seven weather states are active in Pokémon GO, each covering two to three types:
| Weather | Boosted Types |
|---|---|
| Sunny / Clear | Fire, Grass, Ground |
| Rainy | Water, Electric, Bug |
| Partly Cloudy | Normal, Rock |
| Cloudy | Fairy, Fighting, Poison |
| Windy | Psychic, Flying, Dragon |
| Snow | Ice, Steel |
| Fog | Dark, Ghost |
A weather-boosted Pokémon appears on your map with light blue spinning rings around it. That ring signals a specific set of changes to the encounter:
- Wild level cap raised from 30 to 35 — you can catch Level 35 Pokémon in the wild, which is otherwise impossible
- IV floor guaranteed at 4/4/4 — every stat (Attack, Defense, HP) has a minimum of 4 out of 15; a 0 IV weather-boosted Pokémon does not exist
- 25% extra Stardust when caught
- Matching types appear more frequently at spawn points during that weather
- 20% damage bonus (rounded down) for matching-type moves in Gym and Raid Battles
The IV floor is the detail most players miss. A Level 35 Dragonite with a guaranteed 4/4/4 minimum is significantly better catch quality than the same Dragonite on a cloudy day — which could have 0 IVs. During Windy weather, every Dragon-type on your map is L6+ with a 4/4/4 floor. If you’re building a strong raid attacker, this is the most efficient time to stock up.
One caveat from Niantic’s official help: “The weather information in Pokémon GO might occasionally be incorrect or unavailable at some times or in some places.” The game pulls weather data from an API that can lag behind real conditions by 30–60 minutes. If the boosted type doesn’t match what’s outside, the system may simply be catching up.
Weather boosts do not apply in GO Battle League, Field Research rewards, Timed Research, or Trainer Battles. The bonus is strictly for wild encounters and Raid Battles.
Castform is the only Pokémon that physically changes form with weather. It appears as Normal-form in standard conditions, Rain-form during Rainy weather, Snow-form in Snow, and Sunny-form when Sunny. Catching all four forms requires tracking Castform across different weather states.
Items That Directly Modify Spawns
Two items let you add spawns beyond what the base map provides:
Incense creates a personal spawn bubble that only you can see:
- Stationary rate: 1 Pokémon every 5 minutes
- Moving rate: 1 Pokémon per minute (or per 200m traveled, whichever comes first)
- Duration: 60 minutes
- Visibility: Only you see these spawns
Lure Modules are attached to a PokéStop and affect everyone nearby:
- Spawn rate: Every 3–5 minutes
- Duration: 30 minutes
- Visibility: All players within range of the PokéStop
The key tradeoff: Lures are more efficient per Pokémon per hour but lock you to one spot. Incense performs best when you’re walking through new spawn point coverage. At a high-density PokéStop, stacking both gives you the Lure’s public pool and the Incense’s personal pool simultaneously — they run independently.
Specialty Lures (Mossy, Glacial, Magnetic, Rainy) restrict the Lure pool to specific types — Mossy for Grass/Bug/Poison, Glacial for Water/Ice, Magnetic for Electric/Steel/Rock, Rainy for Water/Electric/Bug. These are the closest the game comes to manually setting a mini-biome at a PokéStop.
Practical Tips by Player Type
The spawn system rewards different strategies depending on what you’re trying to accomplish. Here’s how each player type should prioritize the layers:
| Player Type | Priority | Best Spawn Strategy |
|---|---|---|
| New player | Fill Pokédex fast | Cover Forest and City biomes (widest species variety); walk with Incense active to maximize spawn point coverage |
| Casual player | Efficient sessions | Check weather before opening the app — focus on boosted types for the free 25% Stardust bonus; drop a Lure at your regular PokéStop |
| IV hunter | High-quality catches | Prioritize weather-boosted encounters (guaranteed L35 cap / 4/4/4 floor); nest-farm to chain the same species and roll for top IVs |
| Stardust farmer | Maximum Stardust | Combine weather-boosted catches + Star Piece for the best Stardust-per-Pokémon rate available in the wild |
| Completionist | Biome exclusives + rare species | Map all four biomes in your city; Beach biome is required for Wiglett; check nest migration tracking sites weekly |
| PvP-focused | Specific IV spreads | Nest-farm PvP Pokémon during migration windows (low ATK IVs matter for PvP); weather-boosted spawns eliminate the worst rolls, narrowing your search |
If your situation doesn’t fit a single row — for example, you want good IVs and Stardust — combine strategies: hunt weather-boosted encounters in a nest area during a Stardust-boosted event.
Common Mistakes
1. Treating Weather as Visual Decoration
Most players notice the spinning rings but don’t change their behavior. A Level 35 encounter with a 4/4/4 IV floor is a fundamentally better catch than anything in the normal wild pool — the top IV threshold is narrower, and the encounter is already at a higher power level before any Stardust investment. If the weather matches a type you care about, prioritize those spawns.
2. Visiting Nests Without Checking the Migration Date
Nests rotate every 14 days on Thursdays at 00:00 UTC. A nest tracking report from Tuesday may describe a species that rotated out two hours ago. Always check the migration date on any community source before making a trip. Most tracking tools display “X days since last migration” — anything over 13 days means a reset is imminent.
3. Standing Still with Incense
The 5-minute interval when stationary gives you 12 Pokémon per hour from Incense. Walking at a consistent pace cuts that to 1 per minute — 60 Pokémon per hour. If you’re using Incense on a route through multiple spawn points, you’re getting both the Incense spawns and the base map spawns simultaneously. Standing still wastes most of Incense’s value.
4. Assuming Pokémon Appear Everywhere Equally
Biome boundaries mean your City spawn point will never produce a Beach-exclusive like Wiglett regardless of how long you wait. If a specific species isn’t appearing, it’s likely a biome mismatch, not bad luck. Third-party tools that overlay biome data onto the Pokémon GO map can show you exactly which biome each area of your city belongs to before you travel.
5. Confusing Event Spawns with Biome Changes
During Community Days and spotlight events, Niantic overrides the normal biome and nest distributions entirely. A Charmander Community Day floods the map with Fire-types not because the biome changed, but because the event layer sits above all other spawn logic. Normal biome and nest distributions resume once the event ends. If you see unusual spawns, check the current active events before concluding your local pool has changed permanently.
6. Expecting Pokémon in Areas with No Spawn Points
If a rural stretch of road shows no wild Pokémon, the most likely explanation is that there are no active spawn points — not a biome or weather issue. Spawn point density correlates directly with OSM map coverage. Areas with sparse mapping simply don’t qualify for spawn points under Niantic’s L20 cell rules. Incense can generate personal spawns in these areas, but no amount of waiting will produce base-map encounters where no spawn points exist.
FAQ
Why do the same Pokémon appear at the same spots every day?
Because spawn points are fixed locations, not random positions that reset daily. Each point has a biome assignment and a consistent species pool. The point fires at the same clock intervals — if a Caterpie appeared at 3:15 PM, the same spawn point will fire again at 4:15 PM, 5:15 PM, and so on. This looks random at first but becomes highly predictable once you realize the map is a grid of fixed points each operating on their own schedules. Biome and weather shift which species appear at a given point, but the point itself doesn’t move.
Does weather boost increase shiny rates?
No. Weather boosts raise encounter level and guarantee an IV floor, and increase how frequently matching types spawn — but the underlying shiny encounter probability doesn’t change. A weather-boosted Dragonite has the same shiny rate as a non-boosted one. The practical advantage of weather during a shiny hunt is volume: Windy weather puts more Dragon-types on the map, giving you more rolls at the same odds. You’re not improving the probability per encounter; you’re getting more encounters per hour of play.
How do I tell a nest from a spot that just has high natural spawns of one species?
A nest concentrates one species to roughly 80%+ of all spawns in the area — walk through it and you’ll see the same Pokémon almost exclusively. A biome with a high natural rate for a species still shows variety: several Machop alongside Geodude, Mankey, and occasional Primeape in a City/Mountain area would be normal. The reliable test is the ratio. If you walk a full circuit of a park and 8 of 10 spawns are the same species, it’s a nest. If you see 4 species sharing the spawns with one appearing more often, it’s just a biome lean — and it won’t collapse to near-exclusivity like a nest does.