diff --git a/main.c b/main.c
--- a/main.c
+++ b/main.c
@@ -142,7 +142,7 @@ int main(void)
 }
 
 // Read temperature and update global temp vars
-int16_t temp = 0;
+int32_t temp = 0;
 uint8_t temp_frac = 0;
 
 void update_temp() {
@@ -181,10 +181,15 @@ void update_temp() {
         }
 
         if(temp_units == TEMP_UNITS_FAHRENHEIT) {
-            temp *= 10; // fixed point mul by 1.8
-            temp *= 18;
-            temp /= 100;
+            temp *= 9; // fixed point mul by 1.8
+            temp /= 5;
             temp += 32;
+
+            temp_frac *= 9;
+            temp_frac /= 5;
+            temp_frac += 32;
+            temp += temp_frac/100; // add overflow to above
+            temp_frac %= 100;
         }
     }