Add this code to the Custom CSS field on the Style tab of your Weather widget’s settings:
.eapp-weather-detail-locationName {
font-size: 20px;
}
.eapp-weather-detail-currentTemp {
font-size: 20px;
}
.eapp-weather-detail-weatherName {
font-size: 20px;
}
.eapp-weather-forecast-detail-component * {
font-size: 20px;
}
.eapp-weather-forecast-item-date {
font-size: 20px;
}
.eapp-weather-forecast-item-temp {
font-size: 20px;
}
.eapp-weather-daily-item-date {
font-size: 20px;
}
.eapp-weather-daily-item-day {
font-size: 20px;
}
.eapp-weather-daily-item-max {
font-size: 20px;
}
.eapp-weather-daily-item-min {
font-size: 20px;
}