It is very good for environmental use. I measure temp and humidity in urban areas for a study I'm currently conducting. It is really accurate (checked with other sensors). I'm rating it with 4 instead of 5 stars, because it has relatively fast response time ( from 9.6 C to reach room temperature 27.2 C, needed approximately 7 minutes -attached image-), but not as fast as I need for my environmental purposes. Response time decreased dramatically when I attached a fan near the sensors ( 9.7 C to reach 27.2 C needed approximately 2 minutes - attached image-). Overall, I'm very pleased with this data logger.