How to read every hour - Interrupts


I need some help. I have an Arduino Mega and I need this micro to be constantly reading from an ultrasound sensor. The problem is that I want to read from a temperature sensor once per hour. I have done some numbers with the TIMER1, but I am only alowed to throw an interrupt if it is less than 4,19 secons with a 1024 prescaler, because the timer1 has only 16 bits. Therefore, I think using the interrupts are not the best way to do this. Any solution?

Thank you.

Can't you use millis(), like blink without delay?

If, by "constantly reading" you mean regular sensible intervals, perhaps you can just use a counter and read the temperature after a multiple.

Read Ultrasound once a second and count +1
If count +3600, read temp and count =0

Besides using millis() or delay(), you could use an
external clock shield.

I would use an alarms based library such as TimeAlarms.