Route 31

16 species to catch in 1 area of this location, across 5 game versions.

Data from Pokemon HeartGold only: exact levels and the encounter rate for each Pokémon.

in tall grass

Conditional slots 20 for 11 species — time of day, weather, radio and other switches

The game keeps these slots separate from the base ones. Condition sets exclude each other (it cannot be morning and night at once), and the source does not say whether a condition adds a slot or replaces the whole table — so we list them row by row instead of adding them to the rate on the tile.

Pokémon	Conditions	Level	Rate
Caterpie	in the morning	4–5	24%
	during the day	4–5	24%
	radio off, in the morning	4	10%
	radio off, during the day	4	10%
Metapod	in the morning	5	5%
	during the day	5	5%
Pidgey	in the morning	3	20%
	during the day	3	20%
	radio off, in the morning	3	10%
	radio off, during the day	3	10%
Rattata	at night	4–5	25%
	radio off, at night	4	10%
Bellsprout	radio off	3	10%
Hoothoot	at night	5	4%
Spinarak	at night	3	20%
	radio off, at night	3	10%
Linoone	radio on Hoenn Sound	3	10%
Whismur	radio on Hoenn Sound	3–4	20%
Bidoof	radio on Sinnoh Sound	3	10%
Buizel	radio on Sinnoh Sound	3–4	20%

while surfing (Surf)

with the Good Rod

with the Old Rod

with the Super Rod

by headbutting trees (Headbutt)

Conditional slots 6 for 4 species — time of day, weather, radio and other switches

The game keeps these slots separate from the base ones. Condition sets exclude each other (it cannot be morning and night at once), and the source does not say whether a condition adds a slot or replaces the whole table — so we list them row by row instead of adding them to the rate on the tile.

Pokémon	Conditions	Level	Rate
Exeggcute	common tree	3–4	10%
	rare tree	5–6	10%
Hoothoot	common tree	3–4	50%
	rare tree	5–6	50%
Spinarak	rare tree	5–6	15%
Pineco	common tree	3–4	15%

The red marker is Route 31. A diagram, not a world map — distances are not to scale, but directions and connections match the game. The legend below the drawing explains each symbol.

• Route — number inside
• Sea route — Surf only
• City
• Interior — cave, forest, tower; placed next to its entrance
• Path between places
• Path that requires Surf
• Entrance to an interior — not a passage to the other side

Directions read from the map layout in the games — from how the screens connect to each other. We know them for Kanto, Johto, Hoenn and Sinnoh; in other regions you will not see this section, because we have no source for the topology.