Working temperature range
Keep Grammostola grossa around 19–25°C. Use that as a practical captive range and avoid prolonged exposure to temperatures well outside it.
Guarani Giants do not need the enclosure to hit one exact number all day. Normal small room fluctuations are easier to manage than repeated heating and cooling adjustments.
Measure the shelf, not just the room
Check the temperature where the Grammostola grossa enclosure actually sits. Shelves near windows, radiators, computers or external walls can differ from the centre of the room.
A thermometer placed near the enclosure gives more useful information for a Guarani Giant than a reading taken across the room.
Avoid direct heat on the enclosure
Do not attach a heat mat directly to a Grammostola grossa enclosure. Small containers can develop concentrated hot areas that are much warmer than the surrounding room.
If the room is genuinely too cold for Guarani Giants, warm the room instead and check the temperature at enclosure level. That gives a more even and controllable result.
Summer heat
During hot weather, keep Grammostola grossa out of direct sunlight and watch rooms that heat up during the afternoon. A closed window area can become much warmer than expected.
Do not respond to a warm day by soaking the Guarani Giant enclosure. Temperature and substrate moisture are separate husbandry issues.
Winter conditions
In winter, check the coldest part of the day where Grammostola grossa is kept. Rooms can cool overnight even when daytime readings look comfortable.
If room heating is used, remember that it may also dry Guarani Giants enclosures faster. Adjust watering to the actual drying rate rather than assuming winter always means wetter substrate.
Use behaviour as context
Temperature readings for Grammostola grossa should be considered alongside normal feeding, retreat use and moulting. One slightly different reading is less useful than a consistent pattern over time.
If a Guarani Giant suddenly changes behaviour, check temperature along with water, moisture and recent disturbance instead of assuming temperature is the only cause.