Presa la Angostura Weather Records (MXN00026069)

The annual mean temperature here has fallen by 0.08 C (0.00 to 0.16) per decade over 1938 to 2008. In Fahrenheit: 0.15 F (0.01 to 0.29) per decade. The slope is a straight line fitted to 60 complete years; the brackets give its 95 percent interval.

Across 22 years with a frost, the median last spring frost at Presa la Angostura falls on 22 January and the median first autumn frost on 14 December, which leaves a median of 319 days between them.

A day with at least 43.2 mm (1.7 in) of rain is expected about once in 2 years. A day with at least 111.5 mm (4.4 in) of rain is expected about once in 100 years.

The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 55 years of values from 1938 to 2009.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 103.6 mm (4.1 in) in 1966; 96.8 mm (3.8 in) in 1990; 85.6 mm (3.4 in) in 1948.

2 changes were suspected in the annual mean temperature of Presa la Angostura, at 1968 and 1992. Each is measured against neighbouring stations.

• Relative to 5 neighbouring stations, the station's annual mean temperature from 1968 ran 0.9 C (1.6 F) higher than in the years before (likely change).
• Relative to 5 neighbouring stations, the station's annual mean temperature from 1992 ran 0.6 C (1.2 F) lower than in the years before (likely change).