Tag Archives: Portland Weather and Climate

Latitude and Energy: A Beginning Point

45º!  In my previous post I suggest, for reasons of solar gain and intensity, that we gardeners might have better luck choosing plants for our gardens if we chose them from our own latitude, north and south.  The intensity of the sun’s radiation varies with latitude, decreasing as we move away from the equator toward the poles.  Like all horticultural suggestions you should take this with a grain of salt…er, soil.  Follow that line around the Earth from Portland and you can run into a lot of difficulty.  Spin a globe and take a look.  Following the 45 parallel east takes us along the Columbia Gorge, across the Blue Mountains, Hell’s Canyon, the resort town of McCall, Idaho, elevation one mile, the Frank Church River of No Return Wilderness and more of the Rockies, on across the northern Plains, through South Dakota, Minnesota, Michigan, our ‘frozen heartland’ and east through New York and just outside Portland, Maine.  These are highly varied landscapes with conditions almost always colder, different rain patterns, more extreme weather conditions than ours with corresponding plant communities.  In Europe 45º passes through northern Provence, with weather strongly influenced by the adjacent Mediterranean Sea and the massive Sahara Desert that lies beyond, the Piedmont region of Italy, Croatia, the Black Sea, the Steppe country including Uzbekistan, into northern mountainous China and southern Mongolia and finally, the Japanese island of Hokkaido, its capital, Sapporo, a couple degrees south, with its remarkable annual ice festival. 

The list of landmarks found along the southern 45th is very short, as the vast majority of its length is defined by open ocean.  Still it crosses New Zealand’s South Island, only again making landfall in the south of Argentina where it narrows down toward the continent’s southern tip and the Chonos Archipelago of small Chilean islands comprised of submerged mountain tops.  On the later the landscape is dominated by compact cushion plants.  These few places have strong maritime influences and are much effected by the unimpeded weather sweeping off of Antarctica.  Much of this sounds limited and extreme when I think of plants adapted for our region. Continue reading

Winter 0f ’18 -’19: Cloudy, Mild With a Chance of….On Weather, Zones & Plants

It’s 41ºF at 5:30am on Mar. 12 as I begin to write this.  We appear to have come out of the longest sustained ‘cold’ period of the winter of ’18-’19 which began on February 4 and continued through Mar. 11, a period of 36 days.  Over those days we had freezing minimum temps at PDX, the official NOAA reporting station for the Portland area, on 26 of them.  On two of those days, Feb. 6 and 7, PDX recorded the winter’s lowest temp, 23ºF, making it a zn 9a winter, mild for us historically and especially so for the temperate US as a whole, much of which was experiencing its own much colder temps.  It’s mid-March and our high temps have climbed well above what they were and our forecasts call for milder, more ‘normal’ highs and lows now locally.  It looks likely that not only are we going to be on the ‘warm side’ of normal, but that our lows have shifted into a pattern well out of the freezing range.  (State ODF meteorologist, Pete Parsons, calls for a pattern of slightly warmer and drier weather than normal over March, April and May with the highest chance of this during May.) 

While weather consists of moments, recorded data points, we attempt to make sense of it in its patterns over time…our experience of it.  In this we are much like our plants.  Plants too have their ‘expectations’ of the weather and those conditions that take them outside of them, outside their familiar patterns, the relatively quick changes and perturbations, as well as the longer sustained patterns, and extremes, are ‘noticed’ and make a difference.  How does this winter compare? Continue reading