Carnations thrive in temperatures between 50°F to 70°F (10°C to 21°C). They appreciate cool nights, so aim to keep your indoor environment on the cooler side if possible. Additionally, carnations prefer moderate humidity levels. If you live in a dry climate or have indoor heating that dries out the air, consider using a humidifier or placing a tray of water and pebbles near your plants to increase humidity. Consider planting carnations in Australia when the risk of frost has passed. In regions with milder winters, late winter to early spring may be suitable.