On average, the air is driest around September 28 th, when the relative humidity can drop below 66% three days out of four. On the other hand, the air is likely to be most humid around September 23 rd, where relative humidity levels can rise above a very humid 87% three days out of four.
Green cards are valid for 10 years for permanent residents, and 2 years for conditional permanent residents. After this period, the card must be renewed or replaced. Cards issued between January 1977 and August 1989 do not have document numbers or expiration dates and are valid indefinitely.
As a green card holder you may travel abroad multiple times and re-enter, as long as you do not intend to stay outside the U.S. for 1 year or more, however leaving the U.S. for more than 6 months may already cause suspicious of your intent to abandon your residency.