Frost Chart: Vancouver UBC

The attached Frost charts and table have been constructed by Robert Wishlaw from data provided by Environment Canada and redistribution must occur only under the terms of the Environment Canada LIMITED USE SOFTWARE AND DATA PRODUCT AGREEMENT posted at

http://www.climate.weatheroffice.ec.gc.ca/prods_servs/tables/attachment1_e.html

The Vancouver UBC weather station ceased operation in 1995. It was located at latitude 49d.15m., longitude 123d. 15m. and at an altitude of 87 metres.

Code:

Last-Frost DayOfYear FirstFrost DayOfYear Frost-FreeDays

1958-03-10    69     1958-11-15    319        250
1959-03-23    82     1959-11-12    316        234
1960-03-12    72     1960-12-04    339        267
1961-03-06    65     1961-11-16    320        255
1962-03-13    72     1962-12-12    346        274
1963-02-02    33     1963-11-20    324        291
1964-03-13    73     1964-11-14    319        246
1965-03-27    86     1965-11-13    317        231
1966-03-21    80     1966-11-10    314        234
1967-03-13    72     1967-11-28    332        260
1968-03-30    90     1968-11-16    321        231
1969-03-13    72     1969-11-29    333        261
1970-03-09    68     1970-10-27    300        232
1971-03-21    80     1971-10-28    301        221
1972-04-11   102     1972-10-29    303        201
1973-03-17    76     1973-11-01    305        229
1974-03-14    73     1974-11-03    307        234
1975-04-05    95     1975-11-11    315        220
1976-04-01    92     1976-11-26    331        239
1977-03-28    87     1977-11-18    322        235
1978-03-05    64     1978-11-10    314        250
1979-02-22    53     1979-11-13    317        264
1980-03-08    68     1980-11-13    318        250
1981-04-12   102     1981-11-28    332        230
1982-03-17    76     1982-11-11    315        239
1983-04-10   100     1983-11-29    333        233
1984-02-05    36     1984-10-31    305        269
1985-03-10    69     1985-11-11    315        246
1986-02-22    53     1986-11-08    312        259
1987-02-25    56     1987-11-17    321        265
1988-02-03    34     1988-12-14    349        315
1989-03-04    63     1989-12-11    345        282
1990-03-24    83     1990-12-02    336        253
1991-03-05    64     1991-10-28    301        237
1992-01-19    19     1992-11-23    328        309
1993-02-26    57     1993-11-22    326        269
1994-02-25    56     1994-12-02    336        280

 

I don't see any info for the month of January. It's not covered in either of the 2 charts.

Cheers, LPN.

 

Hi LPN:

The chart for the last frost in spring contains the month with the last frost and the two previous months. The chart for the first frost in autumn contains the month with the first frost and the two following months.

The charts were constructed like this because my interest was in determining the probability of first and last frost and not in graphing all occurences of frost during the year.

Robert Wishlaw

 

Here, derived from the table posted earlier in this thread, is a chart, with a linear least square fit trend line, of the annual contiguous frost-free days at UBC 1958-1994.

Robert Wishlaw

 

Interesting, thanks! I wonder how the years after '94 to present compare?
Cheers, LPN.

 

And how long till the first complete frost-free year??

 

It's already happened in Victoria, BC. This according to my brother the weather buff who read this in one of his publications. Not sure of which year or any of the details. Perhaps worthy of a search to find the validity of the claim?

Cheers, LPN.

 

The weather station at Gonzales Heights in Victoria which has temperature records beginning from 1898 recorded its first frost-free winter in 1925-1926. Since then, frost-free winters were recorded on approximate average every five years.

Between February 2 1988 and November 22 1993 there was no frost recorded at the Gonzales Heights station.

At the Agassiz Canada Department of Agriculture weather station the first frost-free winter occured in 2004-2005. Agassiz CDA began keeping temperature records in 1889.

Robert Wishlaw

 

"Between February 2 1988 and November 22 1993 there was no frost recorded at the Gonzales Heights station."

That's astonishing! That's 5 years 9 months (and change) without a frost at the Gonzales station.

Cheers, LPN.

 

Here, with a linear least square fit trend line, are charts of the annual contiguous frost-free days at the Agassiz CDA 1892-2003 and Fort St. James 1895-2003 weather stations.

Robert Wishlaw

 

According to the Canadian Climate Data site for "Victoria Gonzales Hts," data is missing for the winter of 1989. But there surely was hard frost, for a severe Arctic outbreak struck at the end of January. On February 2, the maximum temperature at Victoria Int'l Airport was -8.9°C, with wind peaking well within gale force. Can't imagine how any outdoor site in Greater Victoria could have avoided a freeze.


-Tony

 

I recall that cold snap too. I was so put out that I was prepared to fly into SF for a week to escape the cold. I watched the news and the cold had extended into the Bay area showing footage of people ice skating on frozen ponds there.

Cheers, LPN.

 

Thank you for the information Tony.

Yes the Gonzales Heights station has no records for the period 1988-08-31 to 1993-11-01. No wonder there was no record of frost!

I made a mistake, when I constructed my SQL database from the csv downloads from Environment Canada, by not checking for completely empty records.

Robert Wishlaw

 

These figures are very interesting. In my unprofessional opinion, the figures from Ft. St. James look downright ALARMING.

I'm interested in studying possible winter warming trends here in the Northwest since European settlement began 150 years ago, and implications for the range of both native and introduced plants.

I'm 25 yrs old and have lived in Seattle my whole life. Just in my short lifetime I feel like winters have become more mild, there sure seems like less snow at least. My older relatives have told be stories of large bodies of water in Seattle freezing over: Green Lake and Portage Bay. Its just about impossible to imagine Green Lake freezing nowadays.


If anybody knows where to find similar figures for other locations around Cascadia I would be interested in seeing them. Peace!

 

Hi Symi81:

The Fort St. James trendline is steep but, as it has turned out, not entirely correct.

I have attached, to this post, a redone Fort St. James graph in which the Y axis data extraction base line has been pushed down to -5 Centigrade.

On the first posted Fort St. James graph, with the Y axis data extraction base line set at 0 degrees C., some very low Y values were not the correct number of contiguous frost-free days, for example, the first value of 1, for 1895, should have been 16. This error was caused by my overly simplistic data extraction algorithm.

The new graph is not as steep as the first one but it does show a very significant slope.

It would be interesting to see comparable graphs from other places.

Robert Wishlaw