Solar modules are not working at Night or rainy days. Some types of Solar modules can work partially in cloudy days but if its very dark or rain, they will not work.
Unlike the early days of solar power when systems had to be sized for peak loads, a grid-connected (On-grid solar inverter) PV system seamlessly switches to draw electricity from the utility grid when needed. As such, Solar companies uses an annual production target, averaging out sunnier days with cloudy days.
