These weather parameters are usually related to sunny weather conditions:

• High pressure - Sunny weather typically occurs when high pressure dominates the atmosphere. High pressure brings sinking air which suppresses cloud formation.
• Low humidity - With high pressure and sinking air comes lower humidity. Clear skies allow more sunlight to reach the surface, heating and drying the air.
• Warm temperatures - More direct sunlight reaching the ground leads to warmer daytime highs during sunny periods. The strongest sun and highest temps are seen at equatorial regions.
• UV levels - Sunny skies increase surface UV levels which can be very high in areas like the tropics and at high altitudes without cloud cover/pollution.
• Daytime heating - Land and water absorb more direct heat during extensive sunshine, impacting daily temperature cycles and local weather patterns.

And this is how sunny weather affects people:

• Psychology effects - Sunshine impacts human behavior by naturally elevating mood through vitamin D production and other psychological factors. This effects activity levels, work productivity and more.