How distance from sea affect weather and climate

Landmasses heat up more quickly than water bodies as it receives solar radiation from the sun, but also loses heat more quickly than water. So, in hot seasons, most especially at daytime, the sea or ocean remains cooler than the continent and therefore reduces the temperatures of adjacent lands. In cold seasons and at night, the sea remains warmer and therefore raises the temperatures of places close to it.

We can therefore say that the sea moderates the climate of the coastal areas by keeping the temperatures not too high and not too low, or at means.

On the other hand, the continental interiors are really hot during the hot season and during the day, but very cold during the cold season and at night. We say that the temperatures there are at extremes or the interior lands experience continentality.

Also places close to the sea experience land and sea breezes. During the day as the land gets heated up more quickly than the sea, the hot air over the land rises, and a local low pressure is created over it, and cooler air from the sea rushes to the low-pressure area to take the place of the risen air. this is known as sea breeze.

Source

At night, the sea retains its warmth longer than the land, the air over the sea rises, and there is a local low-pressure zone created over it. Air from the land then rushes to the low-pressure zone over the sea to take the place of the risen air. This is known as land breeze.

Source

Land breezes and sea breezes are responsible for increase in humidity levels, they cause higher precipitation and normal temperature in areas affected. When the winds are very strong it can result in thunderstorms.

Reference
http://www.ecn.ac.uk/what-we-do/education/tutorials-weather-climate/climate/factors-affecting-climate
https://www.toppr.com/bytes/land-breeze-and-sea-breeze/
http://www.physicalgeography.net/fundamentals/7o.html
http://www.bbc.co.uk/schools/gcsebitesize/geography/weather_climate/climate_rev3.shtml