there was a lengthy, well-written account of the recent weather in
yesterday's (8/4/92) New York Times' science section.  it appears that the
global temperature has been lowered by approximately 1degree F in the past
year.  that much, i believe, can be attributed to the eruption of Pinatubo.
however, local variations (shifts in the jet stream, el Nino, etc) can mask
or heighten Pinatubo's effect. here in the northeast temperatures have been
considerably below average since mid-March due to a southward dip in the jet
stream but the Pacific northwest has suffered warmer than normal
temperatures.
 
 i, too, have noticed a dearth of yellowjackets this summer.  it would be
interesting hear reports from the Pacific northwest.