What would happen if there was no moon?

The Earth-Moon system via NASA.

The moon holds a significant relationship with the Earth: if there were no moon, our daily lives as humans would significantly change.

1. Nights would be unbelievably darker,
2.  the water might spread across the planet equally 
3. our days would last between 6 and 12 hours, rather than the 24 hours we experience now
4. tides would be 1/3 of the size they are now
5. we would see an increase in wind speeds.

http://www.crazyhippo.in/understanding-the-universe/

The first and most noticeable shift would be during the night. Nights would be much dark, as the moon reflects light from the sun to the Planet during the night hours. Scientists say that we would not be able to see the hands in front of our face during the night without the moon without the human-made lights.Not only would the nights be darker, but our days would also change.

Just as the Earth exerts a gravitational pull, the moon also exerts a gravitational pull on the Earth. The moon pulls on the Earth and slows down the Earth’s rotation. The moon’s pull creates a bulge near the Earth’s equator, which means there is a lower level of water at the poles.The gravity of the Moon causes the ocean on our planet to rise and fall. There is some friction between the moving water and the spinning Earth as the water moves around. This friction triggers a minor slowing in Earth's rotation. If no moon existed then the water could spread equally across the earth and reduce the amount of friction.
This means that the earth would not slow, which then means that the hours of our days would change. Suddenly, without the moon, our days would last between 6 and 12 hours, rather than the 24 hours we experience now. If our days became this short, then we would have significantly more days in our calendar year. Instead of 365 days in a year, we would have over a thousand.
Since the moon affects the altitude and movement of Earth’s water, our ocean tides would shrink. High tide occurs where the ocean bulges toward the moon, or where the moon pulls the ocean towards it. On the opposite side of our planet, the ocean bulges away from the moon, creating another high tide. The low tides occur on either side of the bulges. Remember that the Earth is rotating, so high tide becomes low tide as the Earth turns.

Scientists suggest that without the moon, tides would be 1/3 of the size they are now. High tides would be much smaller than they are now, and low tides would be even lower. This is because the sun would be influencing the tides, not the moon; however, the sun has a weaker pull, which would decrease the tides.

https://www.freepik.com/free-vector/diagram-showing-earth-tides-with-earth-moon_6550794.htm

The change in the Earth’s rotational speed and a change in the Earth’s tilt would also affect the Earth’s weather patterns. If the moon slows down the Earth’s rotation, then the moon also affects the wind and wind speeds on our planet. Without the moon, we would see an increase in wind speeds. Winds could become much faster and much stronger without the moon.

Additionally, we might  see a change entirely in seasons. The moon affects the angle of the Earth’s tilt. Currently, the Earth sits at a 23.5-degree tilt. This means our planet leans slightly to one side as it sits in space. The tilt creates what we know as seasons and changing weather. Without the pull of the moon, this tilt would change. Either the tilt would become extreme, leading to extreme and severe seasons, or the tilt would decrease, and we would see almost no seasons at all.


Source: https://nineplanets.org/questions/what-would-happen-if-there-was-no-moon/