… and even if you encounter a limit, you can switch to a different sensor - the rtl_433 documentation lists several sensor types manufactured/distributed by Acurite:
[10] Acurite 896 Rain Gauge
[11] Acurite 609TXC Temperature and Humidity Sensor
[40] Acurite 592TXR Temp/Humidity, 592TX Temp, 5n1 Weather Station, 6045 Lightning, 899 Rain, 3N1, Atlas
[41] Acurite 986 Refrigerator / Freezer Thermometer
[...]
It might be cheaper (and more robust) to use a Zigbee approach though:
20 USB for the dongle (e.g., Zigbee 3.0 USB Dongle Plus | ZBDongle-E | ITEAD STUDIO OFFICIAL) plus 10 USD/sensor.
Which way is right really depends on which additional sensor types you are going to use.
Edit:
rtl_433 does support MQTT which makes an additional script unnecessary, see Fleet management using openHAB for an worked example.