The Negro River Valley is one of the most important fruit production regions in Argentina. Every year, meteorological factors produce money lost, because of damages in fruit trees and misuse of farmers' resources. This is a region placed north of the Patagonia plain. Its mean level is 35 m below plain level and its direction is mainly W to E in Neuquén longitude and NW changing to SW in Alto Valle longitude.
An analysis of 29 years statistics in conventional stations is presented and a power spectrum analysis of temperature and wind speed is calculated along the latitude of this valley (39° S) considering four points located from Neuquén to Villa Regina longitude for frequencies from 1.14 10E-5 min -1 to 0.5 min-1 .
The used data are: Neuquén, Alto Valle and Villa Regina conventional meteorological station records and temperature, wind speed and wind direction series, obtained from automatic weather stations registering every minute in Allen, and Colonia Valentina towns. The analysis of 29 years Argentine National Meteorological Service statistics (1961-1990) show the topographical influence in wind direction: in Neuquén, the most frequent direction is W sector, and in Alto Valle, both W and SW show similar frequencies, presenting the conduction of flow within the valley depression.
Most energy is concentrated in 24 hs and 4 days periods, both in temperature and wind speed spectrum. For minor than one day period, temperature series present maximum values in 12 Hs, 6 Hs and 2 Hs periods at the plain station, and 5-7 hs, 3 hs and 2 hs periods for the station within the valley.
Kinetic energy spectrum presents maximum for 5 hs, 3 hs and 1 h period.