As darkness descended around 8 p.m. on July 1, a half hour after sunset (which occurred at 7:32 p.m.), most troops on both sides were exhausted and slept soundly after the day's arduous work. Firing virtually ceased, including pickets. Both armies dispatched pickets to avoid being taken by surprise, however, the moon rose at 7:53 p.m. and was full, so any threatening movements by a large group of enemy soldiers would have been readily detected. A brief stir did occur on the north summit of Culp's Hill from a reconnaissance made by a small group from the 25th Virginia but it was repelled by the 7th Indiana. However, significant reinforcements were moving up on both sides and this might cause issues: a lost segment of the Union Third Corps nearly triggered an encounter against Wilcox's Alabama brigade posted west of Seminary Ridge but the former realized their predicament and were able to quietly withdraw under the cover of darkness. Sporadic picket firing resumed in some places the next day around 4 a.m., or early dawn - sunrise came at 4:35 a.m., and a few isolated cannon shots were heard in the early morning as gunners tested ranges.
The night of July 2 was a different story. While fighting again generally tapered off with the onset of darkness opposite the Union left/Confederate right, it was just getting started on wooded Culp's Hill, not quieting down there until 10 p.m., although occasional outbreaks took place until past midnight. The assault by Hays and Avery on East Cemetery Hill ended not long after 8 p.m., and a contemplated Confederate assault against West Cemetery Hill was called off at the last minute. Again, the nearly full moon was a major factor, rising at 8:38 p.m.
Heavy fighting by artillery and infantry again resumed a few minutes before 4 a.m. on July 3 on Culp's Hill, while Confederate batteries opened at an early hour against the Union center for approximately an hour.
In summary, night fighting was generally avoided because it was often not possible to determine friend from foe, and any movement was difficult and disorienting. Artillery effectiveness was also substantially diminished. Fears multiply among humans with the onset of darkness, and officers are hard pressed to exert control over men whose actions cannot be observed or judged, and thus cannot be relied upon.