Double variable outputs 32767 always instead of user input - c++

Question

I'm writing code that asks about rainfall each month, then outputs yearly total, monthly average, min, and max rain month (index). My code is almost complete, except that instead of outputting the max value the output always shows the max range of the variable type 32767 (e.g. if rain is 70mm and maximum, console shows 32767 always). Thanks for your help. I'm self-learning.
I have tried the following code.
#include<iostream>
using namespace std;
int main(){
const int numMonths = 3;
double monthlyRain[numMonths]={0,0,0};
string monthName[numMonths]= {"Jan", "Feb", "Mar"};
int count = 0;
int indexWettest = 0;
int indexDriest = 0;
double yearTotal=0, monthlyAverage=0;
double monthHighest;
double monthLowest;
monthLowest = monthlyRain[0];
monthHighest = monthlyRain[0];
// enter monthly rain;
for (int count=0; count < numMonths; count++){
cout << "Please enter amount of rain in " << monthName[count] << endl;
cin >> monthlyRain[count];
}
// print month and corresponding rain amount;
cout << "Month --- Rain(mm)" << endl;
for (int count = 0; count < numMonths; count++){
cout << monthName[count] << " " << monthlyRain[count] << endl;
}
// calculate year total;
for (int count = 0; count < numMonths; count++){
yearTotal += monthlyRain[count];
}
// calculate average monthly rainfall;
monthlyAverage = yearTotal/numMonths;
// find month with lowest rainfall;
// find month with highest rainfall;
for (int count = 0; count < numMonths; count++){
if (monthlyRain[count] > monthHighest){
monthHighest = monthlyRain[count+1];
indexWettest = count;
}
}
// PROBLEM IS HERE!;
for (int count = 0; count < numMonths; count++){
if (monthlyRain[count] < monthLowest){
monthLowest = monthlyRain[count];
indexDriest = count;
}
}
cout << "Total yearly rain fall is: " << yearTotal << endl;
cout << "Average monthly rainfall is: " << monthlyAverage << endl;
cout << "The driest month is " << monthName[indexDriest] << " with rain amount of " << monthLowest << endl;
cout << "The wettest month is " << monthName[indexWettest] << " with rain amount of " << monthHighest << endl; //<< monthName[indexWettest];
return 0;
}
Expected result is the user input.

Answer 1

Read compiler warnings.
main.cpp:35:19: warning: 'yearTotal' may be used uninitialized in this function [-
Wmaybe-uninitialized]
yearTotal += monthlyRain[count];
Line that declares yearTotal should be double yearTotal = 0;
Same with other variables. Always initialize them.