INTRODUCTION
Once again its time for the Old Farmer's Almanac to hit the streets and tout how good their weather forecasts have been for the past two-hundred or more years of relying on their "secret formula".  But how often does anyone go back to scrutinize an old forecast to see if it "verified".  I have found that people often don't even remember last week's forecast let alone one that was printed a year ago.

But, here's what I found by looking back at the regional weather forecasts from last November's Western Edition of the Old Farmer's Almanac (Yankee Publishing, Dublin NH,  2000).  The weather forecast section of the Almanac is divided into 16 regions; with Region 16 encompassing the southern two-thirds of California and Region 15 the Pacific Northwest (i.e., western Washington and western Oregon and the northern one-third of California. Each month has a summary of the forecast average temperature and rainfall for the month and how much above or below normal the forecast is.   Here are the actual forecasts from the 2001 Old Farmer's Almanac for Regions 15 and 16 (see Figures 1 & 2).

Fig.1     Fig. 2
(click to enlarge images).

DATA
To evaluate the forecast I looked at how each monthly forecast compared to the actual temperature and rainfall by month for the United States Climate Divisions.  Figures 3-27 are the monthly temperature and precipitation anomalies by climate division as generated by the NOAA-CIRES Climate Diagnostics Center US Climate Divisions Plotting Page.  Data for climate divisions was chosen because of the large number of sites that are used in determining the division average, thus eliminating the bias of a single station.

Figures 3-14.  U.S. Climate Division Precipitation and Temperatures (Nov. 2000 - Apr. 2001)

Figures 15-27.  U.S. Climate Division Precipitation and Temperatures (May 2001 - Oct. 2001)

May 2001	Jun 2001	Jul 2001	Aug 2001	Sep 2001	Oct 2001
					Coming Soon
					Coming Soon

ANALYSIS
The analyses in Table 1 and 2 (below) compare the monthly forecasts for Regions 15 and 16 from the 2001 Old Farmer's Almanac with the actual observed monthly climate division anomalies for temperature and precipitation.  Because of the paucity of rainfall in the California and the Pacific Northwest in the summer months, precipitation for the months May through September was not verified.  Furthermore, if either the forecasts or the observed data were geographically split then separate analyses were done for each geographic area.

The observed data has been color-coded to reflect each of three categories.  Forecasts which were correct are blue.  Those which had the right sign (i.e., above normal observed when above was forecast or below normal observed when below was forecast) but where the quantity was incorrect are coded in yellow.  And forecasts which had the wrong sign are coded red.

SUMMARY
In Region 15, the Pacific Northwest, there were a total of 13 precipitation forecasts.  Only 23% of the forecasts were correct, 38% were quantitatively wrong and 38% were not only wrong but had the wrong sign.  For the 21 Region 15 temperature forecasts 33% verified as correct, 38% were quantitatively wrong and 29% had the wrong sign.  Overall in the Pacific Northwest only 29% of the forecasts verified as being correct.

For California, Region 16, a total of 11 precipitation forecasts and 19 temperature forecasts were evaluated.  Of the precipitation cases 36% were correct, 27% were quantitatively wrong and the remaining 36% had the incorrect sign.  The temperatures for region 16 were only correct 16% of the time, had the wrong sign in 32% of the cases and were quantitatively wrong 53% of the time.  Overall the California forecasts were correct only 23% of the time.

Table 1.  Analysis Region 15 - Pacific Northwest

	Precipitation		Temperature
	Farmer's Almanac	Observed	Farmer's Almanac	Observed
Nov. 00	3" above average	Normal	4º below average	Normal
Dec. 00	Average North 3" above average South	3"-5" below normal 3"-5" below normal	Average North 3º above average South	Normal North 4º-7º above normal South
Jan. 01	1" below average North 2" above average South	4"-8" below normal North 2"-6" below normal South	Average	0º-3º above normal North Normal South
Feb. 01	Average	3"-8" below normal North 0"-3" below normal South	5º below average	0º-2º above normal North 2º-4º above normal South
Mar. 01	1" above average North 2" below average South	0"-3" below normal North 2"-4" below normal South	4º below average North Average South	0º-5º above normal North 2º-4º above normal South
Apr. 01	1" below average	Normal North 0"-1.5" below normal South	1º above average	0º-2º below normal North 2º-4ºbelow normal South
May 01	Average	0"-2" above normal North 0"-2" below normal South	Average	Normal North 3º-6º above normal South
Jun. 01	1" above average North 1" below average South	Normal	3º below average	1º-2º below normal North 2º abv to 2º blo normal South
Jul .01	Average	Normal	Average	1º-3º below normal North 0º-2º below normal South
Aug. 01	Average	0"-1.5" above normal North Normal South	Average	0º-2º above normal North 1º-4º above normal South
Sep. 01	1" above average North 1" below average South	1"-3" below normal North Normal South	1º below average North 1º above average South	0º-3º above normal North 0º-3º above normal North
Oct. 01	4" above average	Coming Soon	2º below average	Coming Soon

Table 2.  Analysis Region 16 - California

	Precipitation		Temperature
	Farmer's Almanac	Observed	Farmer's Almanac	Observed
Nov. 00	2" above average	Below Normal	1º below average	Normal West 4º-7º below normal East
Dec. 00	6" above average North 2" below average South	2"-5" below normal North 0"-3" below normal South	3º above average	0º-4º above normal
Jan. 01	5" above average West 1" below average East	Normal West Normal East	1º above average	1º-3º above normal West 2º-5º above normal East
Feb. 01	1" below average	0"-1" above North 1"-3" above South	3º below average	Normal
Mar. 01	2" below average	Normal	1º below average West 2º above average East	1º-3º above normal West 2º-5º above normal East
Apr. 01	.5" above average	0"-1" above normal North Normal South	Average	2º-3º below normal South
May 01	.2" above average	Normal	1º above average West 2º below average East	3º-6º above normal West 4º-8º above normal East
Jun. 01	.1" below average	Normal	2º above average West 2º below average East	3º-5º above normal West 3º-5º above normal East
Jul .01	Average	Normal	1º above average West 3º below average East	0º-2º below normal West Normal East
Aug. 01	Average	Normal	1º above average West 1º below average East	0º-2º below normal West 1º-3º above normal East
Sep. 01	.2" above average	Normal	2º above average	Normal West 2º-5º above normal East
Oct. 01	.3" above average North .3" below average South	Coming Soon	1º below average	Coming Soon