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 2026-09-14.

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	9% 8% 3 8% 5% 5% 5% 4 6% 8% 37%	154391
	Night	8% 10% 4 10% 6% 5% 5% 4 6% 8% 34%	145435
Transparency	Day	42% 8% 18% 23% 8% 1	154090
	Night	46% 8% 16% 21% 9% 1	145319
Seeing	Day	12% 8% 25% 31% 18% 6%	17916
	Night	12% 6% 30% 36% 15% 2	26781

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	6% 13% 5% 11% 8% 7% 6% 4 6% 7% 28%	4125
	11th to 20th	Day	3 7% 3 10% 7% 7% 6% 5% 8% 10% 34%	4119
	21st to end	Day	5% 11% 4 10% 5% 5% 6% 4 6% 8% 35%	4927
February	1st to 10th	Day	6% 14% 5% 11% 7% 6% 5% 4 7% 8% 28%	1680
	11th to 20th	Day	5% 13% 4 12% 8% 5% 6% 5% 7% 7% 28%	1804
	21st to end	Day	4 12% 6% 11% 8% 8% 8% 6% 7% 8% 24%	1619
March	1st to 10th	Day	3 9% 5% 11% 8% 6% 6% 4 6% 9% 34%	4618
	11th to 20th	Day	6% 11% 4 10% 6% 5% 4 4 5% 8% 36%	5080
	21st to end	Day	10% 16% 6% 14% 5% 4 4 4 5% 7% 24%	5666
April	1st to 10th	Day	9% 11% 4 10% 7% 5% 5% 4 6% 8% 30%	2623
	11th to 20th	Day	12% 12% 4 8% 6% 5% 6% 4 7% 8% 30%	2700
	21st to end	Day	13% 9% 3 7% 5% 6% 5% 5% 6% 8% 32%	2730
May	1st to 10th	Day	10% 7% 3 7% 5% 5% 5% 4 7% 8% 41%	8471
	11th to 20th	Day	12% 10% 4 9% 6% 6% 6% 5% 7% 8% 26%	8755
	21st to end	Day	11% 6% 3 8% 5% 5% 5% 5% 6% 8% 37%	9649
June	1st to 10th	Day	16% 7% 3 8% 5% 5% 5% 4 5% 9% 32%	3150
	11th to 20th	Day	17% 10% 3 9% 7% 6% 5% 4 7% 7% 24%	3150
	21st to end	Day	11% 5% 2 6% 5% 4 6% 5% 7% 10% 37%	3150
July	1st to 10th	Day	7% 5% 2 5% 4 4 5% 4 7% 10% 48%	8820
	11th to 20th	Day	10% 6% 2 7% 5% 4 5% 5% 7% 8% 42%	8820
	21st to end	Day	9% 5% 2 6% 4 4 5% 4 6% 9% 46%	9569
August	1st to 10th	Day	10% 5% 2 6% 4 5% 5% 5% 7% 10% 41%	6565
	11th to 20th	Day	8% 6% 3 6% 5% 4 5% 4 7% 10% 41%	6059
	21st to end	Day	8% 4 2 5% 4 4 5% 4 7% 9% 48%	6570
September	1st to 10th	Day	12% 5% 2 6% 4 4 5% 4 6% 8% 44%	2658
	11th to 20th	Day	14% 7% 2 5% 3 3 4 3 5% 8% 44%	2234
	21st to end	Day	9% 6% 2 6% 4 5% 5% 4 6% 8% 44%	2200
October	1st to 10th	Day	8% 8% 3 8% 4 5% 5% 3 5% 7% 43%	3402
	11th to 20th	Day	8% 8% 4 7% 5% 5% 5% 4 7% 9% 38%	3001
	21st to end	Day	7% 10% 3 8% 5% 5% 6% 4 5% 6% 40%	3173
November	1st to 10th	Day	9% 14% 5% 9% 6% 6% 6% 4 6% 6% 28%	1648
	11th to 20th	Day	6% 12% 5% 13% 6% 5% 5% 4 6% 7% 31%	1539
	21st to end	Day	5% 11% 6% 14% 7% 5% 5% 5% 6% 7% 29%	1470
December	1st to 10th	Day	11% 15% 6% 11% 6% 5% 6% 4 6% 7% 23%	2360
	11th to 20th	Day	6% 14% 5% 12% 7% 6% 7% 4 7% 8% 23%	2712
	21st to end	Day	3 7% 3 10% 6% 5% 5% 3 5% 8% 44%	3575
January	1st to 10th	Night	7% 12% 5% 15% 9% 8% 6% 4 5% 6% 23%	8768
	11th to 20th	Night	2 8% 4 10% 7% 6% 5% 5% 6% 7% 39%	8779
	21st to end	Night	5% 11% 4 11% 6% 5% 5% 4 7% 8% 33%	9311
February	1st to 10th	Night	5% 11% 5% 13% 8% 7% 7% 4 6% 6% 28%	2940
	11th to 20th	Night	5% 13% 5% 10% 6% 6% 6% 5% 7% 7% 29%	2702
	21st to end	Night	5% 12% 4 11% 6% 5% 6% 5% 7% 7% 32%	2186
March	1st to 10th	Night	4 9% 5% 11% 7% 5% 6% 5% 8% 11% 30%	5496
	11th to 20th	Night	5% 10% 4 11% 7% 6% 6% 6% 7% 9% 29%	5138
	21st to end	Night	10% 15% 7% 15% 5% 5% 5% 4 6% 6% 22%	5549
April	1st to 10th	Night	6% 12% 3 9% 6% 7% 5% 4 7% 8% 32%	1996
	11th to 20th	Night	10% 13% 4 10% 5% 5% 6% 5% 7% 8% 26%	1871
	21st to end	Night	12% 9% 3 7% 5% 4 6% 5% 7% 8% 34%	1890
May	1st to 10th	Night	14% 8% 3 6% 4 4 5% 4 6% 7% 40%	4450
	11th to 20th	Night	11% 10% 3 10% 6% 7% 7% 5% 7% 8% 25%	4105
	21st to end	Night	12% 7% 3 8% 5% 5% 5% 4 6% 9% 35%	4522
June	1st to 10th	Night	16% 8% 3 9% 5% 6% 5% 5% 7% 6% 30%	1470
	11th to 20th	Night	16% 10% 5% 9% 8% 6% 7% 5% 7% 8% 20%	1470
	21st to end	Night	11% 5% 3 7% 4 5% 6% 6% 8% 9% 36%	1470
July	1st to 10th	Night	6% 4 2 7% 5% 4 4 4 8% 10% 46%	4140
	11th to 20th	Night	10% 6% 2 7% 5% 5% 5% 4 6% 9% 42%	4140
	21st to end	Night	9% 5% 2 6% 5% 4 5% 5% 6% 9% 45%	4499
August	1st to 10th	Night	14% 7% 3 7% 5% 4 5% 4 6% 8% 37%	3582
	11th to 20th	Night	11% 7% 3 6% 4 5% 5% 5% 7% 9% 37%	4000
	21st to end	Night	8% 4 2 7% 5% 4 5% 4 7% 10% 44%	4578
September	1st to 10th	Night	12% 5% 3 6% 4 4 5% 4 6% 8% 43%	1958
	11th to 20th	Night	13% 7% 2 5% 4 4 4 3 6% 7% 45%	2233
	21st to end	Night	9% 6% 3 7% 4 4 5% 3 7% 8% 44%	2200
October	1st to 10th	Night	9% 7% 3 7% 4 4 5% 4 6% 9% 42%	3792
	11th to 20th	Night	8% 9% 3 7% 5% 5% 5% 4 6% 9% 40%	4145
	21st to end	Night	5% 10% 3 9% 6% 5% 5% 5% 6% 8% 36%	4600
November	1st to 10th	Night	11% 15% 5% 9% 6% 4 4 4 5% 6% 29%	2865
	11th to 20th	Night	6% 13% 5% 12% 6% 6% 5% 4 6% 8% 28%	3077
	21st to end	Night	6% 12% 4 11% 8% 6% 6% 5% 6% 7% 28%	3150
December	1st to 10th	Night	10% 16% 6% 13% 7% 5% 4 4 5% 6% 24%	5040
	11th to 20th	Night	6% 16% 6% 13% 6% 6% 6% 4 7% 8% 22%	5700
	21st to end	Night	3 7% 3 9% 6% 5% 5% 5% 7% 8% 41%	7623

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	55% 7% 10% 16% 12% 1	4125
	11th to 20th	Day	43% 5% 15% 16% 19% 3	4140
	21st to end	Day	45% 7% 19% 24% 4	4928
February	1st to 10th	Day	53% 6% 15% 16% 10% 1	1680
	11th to 20th	Day	51% 9% 13% 16% 10%	1813
	21st to end	Day	53% 9% 13% 18% 7% 1	1619
March	1st to 10th	Day	44% 8% 19% 19% 11%	4618
	11th to 20th	Day	45% 8% 14% 22% 11%	5081
	21st to end	Day	56% 8% 11% 19% 7%	5666
April	1st to 10th	Day	50% 8% 17% 18% 7% 1	2623
	11th to 20th	Day	49% 8% 15% 19% 9%	2700
	21st to end	Day	46% 10% 15% 22% 6% 1	2730
May	1st to 10th	Day	38% 7% 13% 28% 13% 1	8471
	11th to 20th	Day	50% 8% 13% 22% 7%	8759
	21st to end	Day	41% 9% 20% 22% 7% 1	9650
June	1st to 10th	Day	47% 8% 14% 22% 8% 1	3150
	11th to 20th	Day	54% 10% 15% 16% 4	3150
	21st to end	Day	37% 13% 21% 22% 6% 1	3150
July	1st to 10th	Day	31% 7% 22% 29% 10% 1	8746
	11th to 20th	Day	37% 8% 18% 25% 11% 1	8739
	21st to end	Day	33% 8% 23% 27% 9%	9362
August	1st to 10th	Day	36% 9% 23% 28% 4	6547
	11th to 20th	Day	36% 8% 23% 28% 4	6100
	21st to end	Day	31% 7% 24% 32% 6%	6569
September	1st to 10th	Day	37% 8% 21% 25% 7% 2	2658
	11th to 20th	Day	38% 6% 17% 30% 8% 1	2234
	21st to end	Day	35% 9% 19% 26% 9% 2	2200
October	1st to 10th	Day	40% 7% 20% 26% 6%	3402
	11th to 20th	Day	40% 7% 16% 25% 11%	3001
	21st to end	Day	43% 7% 15% 29% 5%	3173
November	1st to 10th	Day	54% 9% 14% 16% 6% 1	1648
	11th to 20th	Day	50% 8% 16% 20% 6%	1539
	21st to end	Day	50% 10% 14% 19% 6% 1	1470
December	1st to 10th	Day	60% 6% 18% 12% 4 1	2360
	11th to 20th	Day	56% 9% 17% 14% 4 1	2714
	21st to end	Day	38% 5% 12% 26% 16% 2	3575
January	1st to 10th	Night	59% 6% 11% 13% 9% 1	8769
	11th to 20th	Night	42% 5% 16% 18% 15% 2	8820
	21st to end	Night	47% 7% 19% 20% 7%	9311
February	1st to 10th	Night	53% 6% 12% 18% 9% 1	2940
	11th to 20th	Night	50% 9% 13% 16% 12% 1	2703
	21st to end	Night	47% 9% 13% 20% 10% 1	2186
March	1st to 10th	Night	44% 8% 18% 22% 8%	5496
	11th to 20th	Night	47% 8% 17% 18% 9% 1	5138
	21st to end	Night	57% 9% 10% 16% 7%	5549
April	1st to 10th	Night	46% 10% 14% 18% 11% 1	1996
	11th to 20th	Night	52% 8% 12% 18% 8% 2	1871
	21st to end	Night	44% 10% 14% 20% 11% 1	1890
May	1st to 10th	Night	41% 6% 9% 26% 15% 2	4447
	11th to 20th	Night	50% 11% 14% 18% 7% 1	4105
	21st to end	Night	42% 10% 20% 20% 7% 1	4526
June	1st to 10th	Night	49% 10% 14% 18% 8% 1	1470
	11th to 20th	Night	56% 11% 14% 13% 5%	1470
	21st to end	Night	39% 11% 21% 23% 5% 1	1470
July	1st to 10th	Night	31% 8% 26% 25% 9% 1	4105
	11th to 20th	Night	37% 8% 17% 28% 8% 2	4098
	21st to end	Night	33% 9% 22% 27% 10%	4401
August	1st to 10th	Night	44% 9% 18% 27% 2	3575
	11th to 20th	Night	39% 9% 23% 23% 5%	4025
	21st to end	Night	34% 7% 19% 33% 7%	4578
September	1st to 10th	Night	36% 9% 17% 25% 11% 2	1958
	11th to 20th	Night	38% 6% 16% 28% 9% 3	2233
	21st to end	Night	36% 10% 15% 25% 13% 3	2200
October	1st to 10th	Night	38% 6% 20% 26% 9% 1	3792
	11th to 20th	Night	39% 7% 14% 31% 9% 1	4145
	21st to end	Night	42% 8% 19% 25% 6%	4600
November	1st to 10th	Night	53% 7% 13% 19% 7% 1	2865
	11th to 20th	Night	51% 8% 15% 17% 8% 1	3077
	21st to end	Night	52% 8% 15% 17% 7% 1	3150
December	1st to 10th	Night	61% 6% 14% 13% 5% 1	5040
	11th to 20th	Night	58% 8% 17% 12% 6%	5697
	21st to end	Night	37% 7% 15% 23% 16% 3	7623

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	5% 9% 30% 34% 17% 4	220
	11th to 20th	Day	8% 9% 35% 35% 11% 3	220
	21st to end	Day	11% 10% 29% 29% 16% 6%	242
February	1st to 10th	Day	14% 8% 29% 32% 14% 3	220
	11th to 20th	Day	10% 6% 29% 36% 15% 4	309
	21st to end	Day	7% 6% 33% 33% 17% 5%	335
March	1st to 10th	Day	10% 9% 31% 30% 18% 3	540
	11th to 20th	Day	8% 6% 33% 33% 15% 5%	540
	21st to end	Day	16% 7% 27% 32% 14% 3	594
April	1st to 10th	Day	11% 13% 32% 29% 13% 3	540
	11th to 20th	Day	15% 12% 23% 30% 15% 5%	532
	21st to end	Day	15% 11% 26% 29% 14% 5%	540
May	1st to 10th	Day	14% 11% 24% 32% 14% 5%	693
	11th to 20th	Day	11% 7% 26% 31% 19% 6%	775
	21st to end	Day	15% 5% 23% 31% 20% 6%	844
June	1st to 10th	Day	20% 8% 24% 30% 15% 3	780
	11th to 20th	Day	18% 9% 23% 24% 20% 6%	780
	21st to end	Day	12% 6% 20% 29% 23% 10%	780
July	1st to 10th	Day	11% 4 18% 34% 23% 10%	771
	11th to 20th	Day	11% 5% 23% 28% 25% 8%	768
	21st to end	Day	8% 6% 16% 33% 27% 10%	849
August	1st to 10th	Day	12% 3 21% 31% 23% 11%	626
	11th to 20th	Day	10% 5% 21% 32% 25% 7%	557
	21st to end	Day	9% 6% 19% 30% 26% 10%	627
September	1st to 10th	Day	15% 8% 23% 27% 21% 6%	570
	11th to 20th	Day	18% 5% 22% 30% 20% 5%	543
	21st to end	Day	12% 14% 28% 27% 16% 3	530
October	1st to 10th	Day	14% 7% 28% 29% 17% 5%	410
	11th to 20th	Day	10% 10% 33% 26% 18% 3	330
	21st to end	Day	14% 11% 34% 29% 10% 2	363
November	1st to 10th	Day	16% 8% 30% 30% 13% 2	330
	11th to 20th	Day	10% 7% 35% 33% 13% 2	256
	21st to end	Day	5% 5% 36% 35% 12% 6%	220
December	1st to 10th	Day	10% 9% 29% 32% 15% 5%	220
	11th to 20th	Day	9% 11% 32% 31% 14% 3	220
	21st to end	Day	9% 7% 22% 39% 18% 5%	242
January	1st to 10th	Night	10% 9% 32% 35% 13% 1	1050
	11th to 20th	Night	10% 9% 36% 32% 11% 1	1050
	21st to end	Night	13% 11% 34% 31% 10% 2	1034
February	1st to 10th	Night	7% 9% 26% 38% 17% 2	840
	11th to 20th	Night	10% 6% 34% 35% 14%	824
	21st to end	Night	8% 5% 30% 35% 18% 3	692
March	1st to 10th	Night	9% 5% 29% 38% 16% 2	840
	11th to 20th	Night	10% 5% 33% 36% 14% 3	840
	21st to end	Night	14% 5% 29% 36% 14% 2	924
April	1st to 10th	Night	11% 7% 30% 36% 14% 2	736
	11th to 20th	Night	15% 8% 28% 38% 11% 1	623
	21st to end	Night	15% 8% 27% 36% 14% 1	630
May	1st to 10th	Night	14% 9% 26% 37% 11% 2	478
	11th to 20th	Night	12% 7% 25% 38% 17% 1	414
	21st to end	Night	19% 5% 25% 33% 17% 2	455
June	1st to 10th	Night	18% 8% 27% 31% 14% 2	420
	11th to 20th	Night	20% 5% 24% 33% 16% 2	420
	21st to end	Night	13% 4 20% 36% 25% 2	420
July	1st to 10th	Night	12% 2 17% 45% 23% 1	410
	11th to 20th	Night	11% 4 21% 42% 21% 1	408
	21st to end	Night	11% 4 17% 39% 27% 2	460
August	1st to 10th	Night	11% 5% 21% 32% 27% 5%	418
	11th to 20th	Night	11% 4 18% 37% 28% 2	558
	21st to end	Night	10% 3 23% 39% 25% 1	693
September	1st to 10th	Night	14% 3 19% 43% 20% 2	677
	11th to 20th	Night	15% 4 20% 42% 18% 1	812
	21st to end	Night	11% 4 32% 40% 11% 2	800
October	1st to 10th	Night	14% 5% 28% 38% 14% 1	800
	11th to 20th	Night	12% 6% 35% 34% 12% 1	800
	21st to end	Night	10% 9% 36% 34% 11% 1	880
November	1st to 10th	Night	17% 7% 34% 32% 9% 1	1020
	11th to 20th	Night	12% 8% 36% 31% 10% 2	1050
	21st to end	Night	10% 5% 37% 34% 12% 1	1050
December	1st to 10th	Night	13% 9% 33% 30% 12% 3	1050
	11th to 20th	Night	11% 7% 36% 32% 13% 1	1050
	21st to end	Night	10% 4 34% 35% 15% 2	1155

Page generated at 2026-09-11 02:11:55. Version ac07

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