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Colorado

John Martin Reservoir

John Martin Reservoir is a Colorado reservoir in Bent County; its largemouth bass shift with the season between shallow cover and deeper water.

Surface
11,685acres
Primary species
Largemouth
§ 01Today on the water · John Martin Reservoirvia Open-Meteo · 21:45 local
Air temp
96.2°F
Barometric
29.66″
↓falling 24h(-0.12)
Wind
5mph
from SSW
Moon
Waning Gibbous
day 20.4 · 68% lit

Air conditions sampled near the lake center, not measured on the water · refreshed ~15 min

§ 03Next 3 daysvia Open-Meteo · interpretation
  1. 2
    sepWed

    Stable window

    hi 97° · lo 61°

    Anytime through the day. Quiet weather day; lean on seasonal pattern and structure.

    ── light w wind · settled

  2. 3
    sepThu

    Stable window

    hi 96° · lo 63°

    Anytime through the day. Quiet weather day; lean on seasonal pattern and structure.

    ── light w wind · settled

  3. 4
    sepFri

    Tougher window

    hi 95° · lo 71°

    Pick the calmest hour and stay flexible. Conditions push hard today; bite likely shrinks. Plan around the calmest gap.

    ── strong se wind · bite likely shrinks

§ 04Field notesColorado

Where it is

John Martin Reservoir sits in Bent County, Colorado, covering about 11,685 acres. Largemouth use the shallow cover and the deeper water as the calendar moves.

Seasonal pattern

Spring. Early warming sends largemouth into the shallows to stage and spawn, the calmest sun-fed water leading the move.

Summer. Warm water moves largemouth onto deeper structure and shade; the early and late hours are the better windows.

Fall. Dropping temperatures pull bait and largemouth back toward shallow water in a wider, roaming feed.

Winter. In cold water fish hold deep and inactive; ease off the pace and keep presentations quiet.

Key structure

  • Transitions from soft to hard bottom
  • Shoreline cover near quick depth changes
  • Shade lines and overhead cover in the warm months
  • Submerged wood, brush, and laydown cover

Let the season pick the water before any one spot does.

Forage

Largemouth track baitfish and the panfish around the same cover on John Martin Reservoir, season to season.

Access

Around John Martin Reservoir in Bent County, public access exists; confirm ramp and launch status locally as levels change through the year.

Regulations

Check current state and local regulations before fishing; limits and seasons can change.

§ 05Sources & field guides

Field guides

Data & references

  • Today's conditions — Open-Meteo, refreshed every ~15 min
  • Moon phase — local astronomical calculation, no external API
  • Lake area, depth, structure — Identity, surface area, coordinates and county/state are from the ProjectD canonical waterbody index (snapshot conus-20260518-v1, group gnis:00203834). Maximum depth and regulation links were not available from an acceptable source and are intentionally omitted.
  • Regulations — verify current state and local regulations before fishing

Last revised · Back to Lake Guide