Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Commercial
Flight Crew Last 90 Days 50; Flight Crew Total 1020; Flight Crew Type 60
Situational Awareness
Deviation / Discrepancy - Procedural FAR; Inflight Event / Encounter Weather / Turbulence
Flight Crew Returned To Departure Airport
Weather
We had filed IFR to get out of GFK. No ice had been reported by [another of] our aircraft that had left prior to us; in fact; one even reported above freezing temperatures aloft. It began to rain as we taxied out. Temperature on the ground was +1 Celsius. I decided to stay in the pattern since the aircraft was wet and not risk hitting a freezing layer on the departure and freezing the moisture to the fuselage; knowing from the weather briefing that there were several freezing levels above us. Other aircraft currently in the traffic pattern had reported no ice; so I was set on staying close by. As soon as we hit traffic pattern altitude the ice reports began to roll in from other aircraft in the pattern. In the 900 feet we climbed to traffic pattern altitude; the temperature had dropped to -1 Celsius. The rain froze to the fuselage and we called Tower to make a full stop. We performed a no-flap landing and had an uneventful arrival back at Grand Forks.
A PA-44 pilot took off in rain at +1C and was surprised when ice started to form as they approached pattern altitude and the temperature had dropped to -1C.  They remained in the pattern and landed ASAP.