In agreement with the above sentiments - usually pick up a pesky summer cold
in June and July and is characterised by an increased susceptibility to 'Sea King Nose' (itchy nose caused by a particular airframe vibration harmonic - well that's my theory and i'm sticking to it!!) and the odd sniffle / sneeze.
Bad hayfever, ie streaming / puffy eyes, blocked sinuses etc i would suggest are a no-no...but if it's mild, then a 'summer cold' is fine i reckon.