Temperature Range

How do I set temperature range from minimum temperature to maximum temperature into this coding?

if (millis() - loopTime >= 5000) {
loopTime = millis();

float t = espert.dht.getTemperature();
float h = espert.dht.getHumidity();

if (!isnan(t) && !isnan(h)) {
String outString = "{"temperature":"" + String(t) + "", ";
outString += ""humidity":"" + String(h) + "", ";
outString += ""name":"" + String(espert.info.getId()) + ""}";
espert.println(outString);
espert.mqtt.publish(outTopic, outString);
// espert.oled.clear();
// espert.oled.println(String("....") + millis());
}
}

delay(100);

If I read to you a list of numbers, how would you work out the biggest and the smallest?

How do I set temperature range from minimum temperature to maximum temperature into this coding?

I'm not exactly sure what you're asking, but the following code will limit t to 50.

if t > 50
     t = 50;

AWOL was giving a hint as to how to find the max and min and remember them.

I am not sure what you want.
Constrain can be used to limit output to an interval, constrain() - Arduino Reference

If you want to keep track of min and max temperature, compare the min value to current temp reading. If current is lower, change min to current. Do the same with max.