Not at this point.
Sending more often than every 15 minutes will reduce the battery lifetime of the Sensor. We are still looking into this feature, and it is a potential feature on our roadmap that could be rolled out after release to existing Sensors.
Also please note that most real-world temperature changes are very slow compared to our default 15min reporting interval. To take a concrete example, an air conditioner that has been configured to a specific temperature will take one hour or more to actually cool down, or heat up, a room to that temperature, depending on the temperature change. During this time, you will have multiple data points to monitor the change in temperature.