other than helicopters

alternate not required 91.169(b)

1 hr before + 1 hr after ETA

• ceiling will be at least 2,000 feet above the airport elevation
• 3 SM visibility

if an alternate is required 91.169(c)

at ETA

• precision: 600 ft ceiling, 2 SM visibility
• non-precision: 800 ft ceiling, 2SM visibility

finally... (for the alternate)

If no instrument approach procedure has been published...

and no special instrument approach procedure has been issued...

the ceiling and visibility minima are those allowing descent from the MEA, approach, and landing under basic VFR