Wetaskiwin
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wetaskiwin clear sky chart from 2005-11-06 to 2024-02-25.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	10% 9% 4 7% 7% 4 5% 6% 6% 8% 35%	77788
	Night	8% 9% 4 8% 7% 4 5% 6% 6% 8% 33%	81464
Transparency	Day	45% 10% 17% 21% 7% 1	77490
	Night	46% 9% 15% 19% 9% 1	81342
Seeing	Day	12% 7% 25% 31% 19% 6%	14382
	Night	12% 6% 29% 35% 15% 2	23657

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	3 12% 4 9% 12% 5% 6% 5% 6% 8% 32%	2219
	11th to 20th	Day	4 9% 5% 8% 8% 4 7% 6% 9% 8% 33%	2199
	21st to end	Day	6% 13% 4 9% 7% 3 5% 5% 5% 8% 35%	2646
February	1st to 10th	Day	7% 14% 6% 10% 8% 4 5% 5% 7% 8% 28%	1520
	11th to 20th	Day	6% 11% 5% 10% 10% 4 7% 6% 7% 7% 27%	1627
	21st to end	Day	4 9% 7% 9% 8% 6% 8% 8% 7% 8% 26%	1421
March	1st to 10th	Day	7% 12% 6% 10% 10% 5% 6% 7% 5% 8% 24%	1800
	11th to 20th	Day	8% 10% 5% 8% 6% 3 5% 6% 7% 8% 34%	1964
	21st to end	Day	10% 13% 6% 10% 7% 3 6% 7% 6% 8% 24%	2198
April	1st to 10th	Day	10% 10% 5% 9% 8% 4 5% 6% 6% 8% 29%	2248
	11th to 20th	Day	13% 12% 4 7% 6% 4 5% 5% 6% 8% 29%	2310
	21st to end	Day	14% 9% 3 6% 6% 4 6% 6% 6% 9% 32%	2340
May	1st to 10th	Day	11% 10% 4 8% 7% 4 6% 7% 6% 7% 29%	2594
	11th to 20th	Day	9% 5% 3 6% 6% 4 6% 6% 6% 9% 39%	2654
	21st to end	Day	19% 7% 3 6% 6% 4 5% 5% 6% 7% 33%	2917
June	1st to 10th	Day	16% 7% 4 7% 6% 3 5% 5% 5% 10% 31%	2700
	11th to 20th	Day	19% 9% 3 7% 7% 4 6% 5% 7% 8% 25%	2700
	21st to end	Day	11% 5% 3 5% 5% 3 6% 7% 7% 11% 38%	2700
July	1st to 10th	Day	11% 6% 3 6% 6% 4 5% 5% 7% 9% 39%	2700
	11th to 20th	Day	11% 5% 2 6% 5% 3 6% 7% 8% 9% 38%	2700
	21st to end	Day	9% 4 2 4 5% 3 5% 6% 6% 9% 47%	2938
August	1st to 10th	Day	10% 5% 2 5% 6% 4 5% 7% 7% 9% 39%	2558
	11th to 20th	Day	9% 5% 2 5% 6% 3 4 5% 7% 10% 44%	2355
	21st to end	Day	10% 6% 2 5% 5% 3 4 4 7% 9% 44%	2574
September	1st to 10th	Day	12% 6% 2 5% 6% 3 5% 5% 6% 8% 42%	2279
	11th to 20th	Day	15% 7% 3 4 4 2 4 4 5% 8% 43%	1980
	21st to end	Day	9% 6% 3 6% 5% 4 5% 5% 6% 8% 44%	1980
October	1st to 10th	Day	11% 10% 4 7% 6% 4 5% 4 4 5% 41%	1872
	11th to 20th	Day	10% 7% 4 5% 6% 3 5% 5% 7% 8% 40%	1661
	21st to end	Day	9% 13% 4 7% 7% 4 7% 7% 5% 7% 32%	1769
November	1st to 10th	Day	9% 13% 7% 8% 8% 4 6% 6% 6% 7% 27%	1488
	11th to 20th	Day	6% 11% 6% 11% 7% 4 5% 5% 6% 7% 31%	1393
	21st to end	Day	6% 9% 6% 12% 8% 4 6% 6% 6% 7% 31%	1330
December	1st to 10th	Day	6% 12% 6% 10% 10% 5% 8% 6% 6% 6% 26%	1330
	11th to 20th	Day	5% 11% 5% 10% 8% 4 6% 6% 7% 9% 28%	1682
	21st to end	Day	4 9% 3 7% 6% 4 6% 5% 5% 8% 43%	2442
January	1st to 10th	Night	4 11% 5% 12% 10% 6% 7% 6% 6% 7% 27%	4726
	11th to 20th	Night	4 8% 4 9% 11% 5% 6% 6% 7% 6% 33%	4699
	21st to end	Night	6% 13% 5% 9% 8% 4 5% 5% 6% 8% 33%	5040
February	1st to 10th	Night	5% 10% 5% 12% 9% 6% 6% 6% 6% 7% 28%	2660
	11th to 20th	Night	6% 12% 5% 9% 7% 5% 6% 6% 7% 8% 29%	2439
	21st to end	Night	6% 10% 4 9% 7% 4 6% 7% 7% 7% 33%	1928
March	1st to 10th	Night	6% 11% 5% 10% 9% 5% 6% 6% 6% 9% 28%	2160
	11th to 20th	Night	8% 9% 4 10% 8% 4 6% 7% 7% 10% 29%	1994
	21st to end	Night	9% 13% 6% 9% 5% 4 6% 5% 7% 9% 27%	2156
April	1st to 10th	Night	7% 9% 4 8% 7% 5% 6% 5% 8% 8% 32%	1711
	11th to 20th	Night	11% 12% 5% 9% 6% 3 6% 6% 6% 8% 28%	1601
	21st to end	Night	13% 8% 3 5% 7% 3 6% 6% 6% 9% 34%	1620
May	1st to 10th	Night	12% 10% 5% 6% 8% 3 7% 7% 7% 8% 27%	1360
	11th to 20th	Night	10% 8% 4 8% 7% 4 5% 5% 6% 8% 35%	1239
	21st to end	Night	19% 7% 3 8% 6% 4 5% 6% 5% 7% 30%	1358
June	1st to 10th	Night	17% 7% 3 7% 6% 4 6% 7% 7% 6% 30%	1260
	11th to 20th	Night	17% 10% 5% 9% 8% 3 7% 6% 6% 9% 21%	1260
	21st to end	Night	11% 5% 3 5% 6% 4 6% 8% 8% 9% 36%	1260
July	1st to 10th	Night	11% 6% 3 6% 7% 4 4 5% 7% 10% 38%	1260
	11th to 20th	Night	10% 5% 2 6% 7% 5% 5% 5% 7% 12% 35%	1260
	21st to end	Night	10% 4 3 5% 5% 2 5% 7% 6% 8% 45%	1379
August	1st to 10th	Night	11% 5% 3 6% 6% 3 6% 5% 6% 11% 39%	1378
	11th to 20th	Night	11% 6% 3 4 6% 3 5% 6% 8% 10% 40%	1545
	21st to end	Night	9% 5% 3 7% 6% 3 5% 6% 6% 9% 41%	1782
September	1st to 10th	Night	12% 5% 3 5% 5% 3 4 6% 6% 8% 41%	1678
	11th to 20th	Night	13% 7% 3 5% 5% 3 4 4 5% 7% 44%	1980
	21st to end	Night	10% 6% 3 6% 6% 3 5% 4 6% 7% 44%	1980
October	1st to 10th	Night	11% 8% 4 6% 5% 3 5% 4 6% 8% 39%	2088
	11th to 20th	Night	8% 9% 4 7% 6% 3 5% 5% 6% 8% 39%	2297
	21st to end	Night	6% 10% 4 9% 9% 4 5% 6% 7% 8% 34%	2574
November	1st to 10th	Night	11% 14% 6% 8% 7% 3 5% 5% 5% 7% 29%	2585
	11th to 20th	Night	7% 12% 6% 10% 7% 4 5% 5% 5% 8% 29%	2783
	21st to end	Night	6% 10% 6% 10% 9% 5% 6% 6% 6% 8% 29%	2850
December	1st to 10th	Night	8% 12% 5% 10% 9% 4 5% 5% 5% 7% 31%	2850
	11th to 20th	Night	5% 13% 5% 10% 7% 4 6% 5% 6% 9% 28%	3510
	21st to end	Night	3 7% 4 7% 6% 4 5% 6% 6% 9% 43%	5214

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	50% 10% 13% 19% 8% 1	2219
	11th to 20th	Day	45% 7% 12% 14% 20% 2	2220
	21st to end	Day	46% 9% 17% 24% 5%	2646
February	1st to 10th	Day	53% 6% 15% 16% 9% 1	1520
	11th to 20th	Day	53% 10% 14% 16% 8%	1636
	21st to end	Day	51% 9% 14% 18% 7%	1421
March	1st to 10th	Day	56% 9% 16% 15% 4	1800
	11th to 20th	Day	45% 8% 14% 21% 10% 1	1965
	21st to end	Day	54% 11% 16% 15% 4	2198
April	1st to 10th	Day	50% 8% 17% 17% 7% 1	2248
	11th to 20th	Day	51% 8% 14% 19% 8%	2310
	21st to end	Day	46% 10% 16% 21% 6% 2	2340
May	1st to 10th	Day	49% 10% 16% 17% 7%	2594
	11th to 20th	Day	39% 9% 15% 26% 10%	2658
	21st to end	Day	48% 8% 14% 20% 10%	2918
June	1st to 10th	Day	48% 9% 15% 22% 6%	2700
	11th to 20th	Day	55% 10% 16% 15% 4	2700
	21st to end	Day	36% 14% 23% 22% 5% 1	2700
July	1st to 10th	Day	39% 11% 21% 24% 5% 1	2626
	11th to 20th	Day	38% 14% 24% 22% 2	2619
	21st to end	Day	33% 11% 26% 26% 4	2775
August	1st to 10th	Day	37% 14% 23% 23% 3	2540
	11th to 20th	Day	33% 12% 25% 23% 7%	2355
	21st to end	Day	34% 10% 22% 25% 8% 1	2574
September	1st to 10th	Day	38% 9% 21% 23% 7% 2	2279
	11th to 20th	Day	39% 6% 19% 28% 7%	1980
	21st to end	Day	36% 9% 20% 25% 9% 2	1980
October	1st to 10th	Day	46% 7% 16% 20% 10%	1872
	11th to 20th	Day	39% 10% 19% 22% 10%	1661
	21st to end	Day	48% 10% 12% 21% 8%	1769
November	1st to 10th	Day	55% 9% 14% 15% 6% 1	1488
	11th to 20th	Day	51% 8% 16% 20% 6%	1393
	21st to end	Day	49% 10% 15% 19% 6% 1	1330
December	1st to 10th	Day	56% 7% 12% 15% 8% 2	1330
	11th to 20th	Day	48% 11% 17% 16% 6% 1	1684
	21st to end	Day	38% 6% 11% 25% 17% 3	2442
January	1st to 10th	Night	52% 9% 15% 16% 6% 2	4726
	11th to 20th	Night	48% 7% 13% 15% 14% 2	4740
	21st to end	Night	47% 8% 16% 20% 7%	5040
February	1st to 10th	Night	53% 7% 13% 18% 8% 1	2660
	11th to 20th	Night	49% 10% 14% 16% 10% 1	2440
	21st to end	Night	45% 10% 14% 20% 11% 1	1928
March	1st to 10th	Night	51% 10% 13% 19% 6% 1	2160
	11th to 20th	Night	48% 9% 13% 19% 10% 1	1994
	21st to end	Night	50% 10% 16% 17% 6% 1	2156
April	1st to 10th	Night	45% 11% 14% 19% 10% 1	1711
	11th to 20th	Night	52% 8% 12% 18% 8% 2	1601
	21st to end	Night	44% 10% 16% 19% 10% 2	1620
May	1st to 10th	Night	50% 10% 13% 18% 9% 1	1360
	11th to 20th	Night	44% 8% 13% 21% 12% 1	1239
	21st to end	Night	50% 9% 14% 16% 10% 2	1358
June	1st to 10th	Night	50% 11% 14% 18% 7%	1260
	11th to 20th	Night	57% 12% 15% 12% 5%	1260
	21st to end	Night	38% 13% 22% 22% 5% 1	1260
July	1st to 10th	Night	38% 11% 19% 25% 5% 1	1225
	11th to 20th	Night	39% 15% 22% 19% 5%	1218
	21st to end	Night	32% 11% 24% 27% 5%	1302
August	1st to 10th	Night	37% 15% 21% 24% 3	1371
	11th to 20th	Night	36% 11% 23% 23% 6% 1	1545
	21st to end	Night	37% 11% 16% 26% 9% 1	1782
September	1st to 10th	Night	37% 10% 17% 23% 11% 2	1678
	11th to 20th	Night	39% 6% 16% 28% 9% 3	1980
	21st to end	Night	36% 10% 14% 24% 13% 3	1980
October	1st to 10th	Night	42% 8% 15% 23% 11% 1	2088
	11th to 20th	Night	42% 8% 16% 25% 9% 1	2297
	21st to end	Night	45% 11% 16% 21% 7% 1	2574
November	1st to 10th	Night	54% 7% 13% 18% 7% 1	2585
	11th to 20th	Night	52% 9% 14% 17% 7% 1	2783
	21st to end	Night	51% 8% 16% 17% 6% 1	2850
December	1st to 10th	Night	53% 7% 11% 18% 9% 2	2850
	11th to 20th	Night	51% 9% 17% 16% 6%	3507
	21st to end	Night	35% 8% 16% 21% 16% 4	5214

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	3 9% 30% 33% 19% 5%	180
	11th to 20th	Day	7% 7% 33% 36% 14% 4	180
	21st to end	Day	11% 10% 29% 28% 16% 7%	198
February	1st to 10th	Day	16% 9% 28% 31% 12% 3	180
	11th to 20th	Day	11% 5% 31% 33% 15% 4	252
	21st to end	Day	4 5% 31% 35% 19% 6%	263
March	1st to 10th	Day	11% 9% 30% 30% 18% 3	420
	11th to 20th	Day	7% 5% 34% 34% 15% 6%	420
	21st to end	Day	15% 6% 26% 34% 15% 3	462
April	1st to 10th	Day	10% 13% 32% 31% 11% 3	420
	11th to 20th	Day	16% 8% 21% 32% 16% 6%	412
	21st to end	Day	15% 10% 28% 29% 13% 4	420
May	1st to 10th	Day	14% 10% 21% 33% 15% 7%	551
	11th to 20th	Day	10% 5% 25% 33% 22% 6%	625
	21st to end	Day	17% 4 22% 30% 20% 6%	679
June	1st to 10th	Day	18% 7% 24% 31% 17% 3	630
	11th to 20th	Day	20% 8% 20% 26% 20% 6%	630
	21st to end	Day	11% 4 20% 30% 23% 10%	630
July	1st to 10th	Day	12% 4 18% 33% 23% 10%	621
	11th to 20th	Day	11% 5% 23% 29% 25% 7%	618
	21st to end	Day	7% 6% 17% 33% 27% 10%	684
August	1st to 10th	Day	13% 2 20% 31% 22% 12%	498
	11th to 20th	Day	9% 5% 20% 32% 26% 7%	437
	21st to end	Day	10% 7% 19% 29% 26% 9%	495
September	1st to 10th	Day	15% 9% 25% 28% 19% 4	450
	11th to 20th	Day	19% 6% 24% 29% 18% 4	450
	21st to end	Day	13% 15% 24% 27% 18% 4	450
October	1st to 10th	Day	16% 8% 26% 28% 17% 5%	342
	11th to 20th	Day	11% 9% 31% 29% 18% 3	270
	21st to end	Day	15% 12% 31% 30% 11% 2	297
November	1st to 10th	Day	15% 9% 29% 30% 14% 3	270
	11th to 20th	Day	11% 7% 32% 35% 12% 2	210
	21st to end	Day	3 6% 38% 34% 12% 6%	180
December	1st to 10th	Day	8% 7% 27% 35% 17% 6%	180
	11th to 20th	Day	9% 10% 31% 32% 16% 3	180
	21st to end	Day	8% 7% 21% 40% 20% 5%	198
January	1st to 10th	Night	9% 9% 32% 35% 14% 1	950
	11th to 20th	Night	10% 8% 35% 33% 12% 2	950
	21st to end	Night	13% 11% 32% 31% 11% 2	936
February	1st to 10th	Night	8% 10% 26% 37% 18% 2	760
	11th to 20th	Night	11% 6% 35% 33% 15%	744
	21st to end	Night	8% 4 27% 38% 20% 4	610
March	1st to 10th	Night	10% 5% 28% 38% 17% 2	720
	11th to 20th	Night	10% 4 31% 37% 15% 3	720
	21st to end	Night	14% 4 29% 36% 15% 3	792
April	1st to 10th	Night	11% 6% 29% 35% 15% 3	631
	11th to 20th	Night	15% 7% 27% 38% 12% 1	533
	21st to end	Night	16% 7% 26% 36% 15% 1	540
May	1st to 10th	Night	14% 8% 26% 37% 12% 2	410
	11th to 20th	Night	12% 6% 24% 40% 18% 1	354
	21st to end	Night	20% 4 25% 31% 17% 2	389
June	1st to 10th	Night	18% 7% 24% 34% 14% 3	360
	11th to 20th	Night	22% 5% 22% 33% 18% 2	360
	21st to end	Night	12% 3 20% 38% 25% 2	360
July	1st to 10th	Night	14% 1 16% 44% 24% 1	350
	11th to 20th	Night	11% 4 21% 42% 20% 1	348
	21st to end	Night	10% 4 18% 38% 27% 2	394
August	1st to 10th	Night	11% 4 21% 31% 27% 6%	358
	11th to 20th	Night	12% 4 18% 36% 28% 2	477
	21st to end	Night	10% 3 23% 38% 26% 1	594
September	1st to 10th	Night	15% 2 20% 42% 19% 3	580
	11th to 20th	Night	15% 4 22% 40% 17% 1	720
	21st to end	Night	11% 3 30% 42% 12% 2	720
October	1st to 10th	Night	15% 4 28% 38% 15% 1	720
	11th to 20th	Night	13% 5% 35% 33% 13% 2	720
	21st to end	Night	9% 8% 36% 35% 11% 1	792
November	1st to 10th	Night	18% 6% 32% 33% 10% 1	920
	11th to 20th	Night	13% 8% 36% 30% 10% 2	950
	21st to end	Night	9% 6% 39% 34% 11% 1	950
December	1st to 10th	Night	12% 9% 31% 31% 13% 3	950
	11th to 20th	Night	11% 6% 36% 33% 14% 2	950
	21st to end	Night	9% 4 34% 34% 16% 3	1045

Page generated at 2024-02-22 04:05:46. Version ac07

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