Saskatoon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saskatoon clear sky chart from 2005-11-06 to 2025-11-03.

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%	130545
	Night	7% 9% 4 10% 6% 6% 5% 4 6% 8% 36%	128158
Transparency	Day	44% 5% 17% 25% 9% 1	130245
	Night	46% 5% 16% 24% 9% 1	128038
Seeing	Day	13% 7% 26% 31% 17% 5%	17158
	Night	12% 5% 28% 37% 15% 2	26356

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	5% 14% 6% 13% 9% 9% 7% 4 7% 7% 20%	3161
	11th to 20th	Day	4 8% 4 10% 8% 10% 7% 5% 9% 8% 27%	3159
	21st to end	Day	7% 12% 5% 12% 6% 6% 5% 4 6% 7% 30%	3747
February	1st to 10th	Day	8% 13% 5% 12% 7% 7% 7% 6% 6% 8% 22%	1680
	11th to 20th	Day	6% 12% 6% 12% 7% 5% 5% 6% 7% 7% 27%	1755
	21st to end	Day	5% 10% 5% 12% 10% 6% 8% 6% 6% 8% 24%	1513
March	1st to 10th	Day	5% 11% 5% 15% 9% 7% 6% 4 6% 7% 25%	4500
	11th to 20th	Day	6% 12% 6% 16% 7% 4 5% 3 5% 7% 29%	4949
	21st to end	Day	10% 12% 3 9% 6% 5% 5% 4 6% 7% 33%	5762
April	1st to 10th	Day	8% 11% 4 7% 6% 6% 5% 5% 7% 8% 35%	2400
	11th to 20th	Day	12% 13% 4 10% 5% 5% 5% 4 6% 6% 31%	2471
	21st to end	Day	13% 10% 3 9% 5% 6% 5% 4 5% 7% 34%	2786
May	1st to 10th	Day	14% 9% 3 6% 3 4 4 3 6% 7% 42%	6340
	11th to 20th	Day	11% 9% 4 9% 6% 6% 6% 5% 7% 7% 29%	6298
	21st to end	Day	11% 8% 3 6% 5% 5% 5% 4 6% 7% 41%	7487
June	1st to 10th	Day	12% 7% 3 7% 5% 5% 4 5% 7% 9% 36%	3200
	11th to 20th	Day	20% 8% 3 7% 6% 4 5% 5% 7% 7% 27%	3200
	21st to end	Day	12% 6% 3 6% 5% 6% 5% 5% 7% 9% 36%	3200
July	1st to 10th	Day	6% 4 2 5% 4 5% 5% 5% 7% 10% 48%	7058
	11th to 20th	Day	10% 5% 2 6% 4 4 4 5% 7% 9% 44%	6780
	21st to end	Day	6% 3 1 4 4 3 4 4 6% 10% 55%	7215
August	1st to 10th	Day	10% 5% 2 6% 4 4 5% 4 6% 8% 45%	4552
	11th to 20th	Day	7% 5% 2 5% 4 4 4 4 6% 10% 48%	4398
	21st to end	Day	12% 5% 1 4 3 3 4 3 5% 8% 52%	4552
September	1st to 10th	Day	10% 5% 2 7% 4 4 3 4 7% 8% 48%	2400
	11th to 20th	Day	13% 7% 2 7% 4 4 4 4 6% 8% 41%	2400
	21st to end	Day	9% 4 2 5% 4 4 4 3 5% 8% 52%	2125
October	1st to 10th	Day	10% 9% 2 5% 3 3 4 3 5% 9% 47%	3270
	11th to 20th	Day	7% 6% 2 7% 4 4 5% 4 9% 12% 39%	3190
	21st to end	Day	6% 9% 4 10% 5% 6% 7% 4 7% 7% 36%	3097
November	1st to 10th	Day	14% 15% 5% 10% 5% 3 4 3 4 5% 31%	1584
	11th to 20th	Day	9% 15% 6% 14% 7% 7% 5% 4 4 6% 24%	1600
	21st to end	Day	8% 13% 6% 11% 6% 6% 6% 5% 6% 6% 27%	1453
December	1st to 10th	Day	7% 12% 4 12% 8% 7% 8% 4 6% 9% 24%	2012
	11th to 20th	Day	7% 11% 6% 13% 11% 7% 8% 4 4 6% 22%	2259
	21st to end	Day	3 9% 4 12% 7% 5% 6% 4 6% 6% 37%	2992
January	1st to 10th	Night	4 11% 5% 14% 10% 9% 7% 5% 8% 8% 20%	6766
	11th to 20th	Night	4 9% 4 13% 9% 10% 8% 5% 6% 7% 24%	6739
	21st to end	Night	5% 11% 4 12% 7% 6% 5% 4 7% 9% 30%	7218
February	1st to 10th	Night	7% 11% 5% 12% 8% 6% 6% 5% 7% 7% 24%	2735
	11th to 20th	Night	5% 10% 4 11% 6% 5% 6% 5% 7% 7% 33%	2532
	21st to end	Night	3 9% 4 9% 8% 6% 7% 6% 7% 8% 34%	2117
March	1st to 10th	Night	6% 11% 6% 13% 6% 7% 8% 5% 7% 8% 24%	5374
	11th to 20th	Night	7% 9% 5% 13% 6% 6% 5% 4 6% 9% 29%	5045
	21st to end	Night	9% 10% 4 10% 6% 5% 5% 5% 7% 8% 31%	5199
April	1st to 10th	Night	6% 9% 3 7% 6% 5% 5% 4 6% 8% 42%	2000
	11th to 20th	Night	10% 12% 3 7% 6% 6% 6% 4 6% 7% 32%	1876
	21st to end	Night	13% 10% 3 8% 6% 5% 4 3 6% 7% 36%	1613
May	1st to 10th	Night	14% 8% 3 8% 5% 4 4 3 4 5% 43%	3640
	11th to 20th	Night	11% 10% 4 9% 5% 6% 6% 5% 6% 8% 30%	3618
	21st to end	Night	13% 8% 3 6% 4 4 4 3 4 7% 44%	3372
June	1st to 10th	Night	11% 6% 2 6% 5% 4 5% 4 8% 9% 40%	1200
	11th to 20th	Night	18% 8% 3 9% 4 5% 4 5% 5% 8% 33%	1200
	21st to end	Night	12% 4 2 6% 4 4 4 4 7% 9% 44%	1200
July	1st to 10th	Night	8% 5% 1 5% 4 4 4 5% 7% 10% 47%	2898
	11th to 20th	Night	9% 4 1 4 4 5% 5% 5% 7% 10% 47%	3180
	21st to end	Night	4 3 2 4 3 3 3 4 6% 7% 61%	3634
August	1st to 10th	Night	8% 4 2 5% 4 3 4 4 6% 8% 53%	2608
	11th to 20th	Night	5% 3 2 5% 4 4 6% 5% 8% 11% 47%	2659
	21st to end	Night	8% 4 2 5% 3 3 4 4 5% 7% 53%	3357
September	1st to 10th	Night	9% 4 2 6% 4 5% 4 4 6% 8% 49%	2000
	11th to 20th	Night	11% 6% 2 6% 3 4 5% 3 7% 9% 44%	2000
	21st to end	Night	8% 6% 2 4 4 3 4 3 5% 7% 55%	2274
October	1st to 10th	Night	10% 7% 2 5% 4 4 4 3 5% 7% 49%	3920
	11th to 20th	Night	6% 6% 2 7% 4 5% 4 4 5% 8% 50%	3925
	21st to end	Night	8% 9% 3 9% 4 4 5% 4 5% 8% 42%	4702
November	1st to 10th	Night	15% 14% 5% 8% 6% 5% 4 4 5% 7% 27%	2759
	11th to 20th	Night	7% 14% 6% 13% 7% 6% 5% 3 6% 6% 26%	2800
	21st to end	Night	7% 13% 5% 12% 7% 5% 5% 3 6% 9% 28%	2945
December	1st to 10th	Night	9% 13% 7% 13% 8% 7% 6% 4 5% 6% 22%	5156
	11th to 20th	Night	6% 13% 6% 13% 8% 7% 8% 6% 6% 7% 20%	5933
	21st to end	Night	3 7% 4 13% 9% 6% 5% 3 5% 5% 41%	7964

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	62% 4 10% 18% 6%	3161
	11th to 20th	Day	51% 5% 14% 18% 11%	3180
	21st to end	Day	53% 6% 21% 15% 4	3747
February	1st to 10th	Day	58% 6% 12% 16% 8%	1680
	11th to 20th	Day	53% 4 12% 22% 9% 1	1764
	21st to end	Day	57% 5% 11% 19% 8%	1513
March	1st to 10th	Day	57% 5% 17% 14% 6%	4500
	11th to 20th	Day	55% 6% 15% 18% 5%	4950
	21st to end	Day	49% 5% 12% 23% 11%	5762
April	1st to 10th	Day	44% 6% 14% 24% 11%	2400
	11th to 20th	Day	53% 4 12% 19% 11% 1	2471
	21st to end	Day	49% 4 13% 24% 9% 1	2786
May	1st to 10th	Day	41% 4 12% 25% 16% 2	6340
	11th to 20th	Day	50% 6% 10% 24% 9% 1	6302
	21st to end	Day	41% 5% 12% 27% 14% 2	7487
June	1st to 10th	Day	44% 4 14% 25% 11% 1	3200
	11th to 20th	Day	53% 6% 14% 20% 7% 1	3200
	21st to end	Day	42% 6% 19% 24% 8%	3200
July	1st to 10th	Day	29% 8% 26% 30% 7%	6982
	11th to 20th	Day	34% 7% 17% 36% 5%	6699
	21st to end	Day	24% 6% 23% 36% 10%	7011
August	1st to 10th	Day	36% 6% 22% 29% 8%	4536
	11th to 20th	Day	30% 6% 21% 36% 6%	4440
	21st to end	Day	31% 4 20% 35% 9%	4551
September	1st to 10th	Day	33% 4 17% 31% 13% 2	2400
	11th to 20th	Day	41% 5% 19% 26% 8% 1	2400
	21st to end	Day	31% 4 16% 34% 13% 2	2125
October	1st to 10th	Day	35% 4 26% 26% 10%	3270
	11th to 20th	Day	36% 4 20% 33% 7%	3190
	21st to end	Day	45% 5% 19% 26% 5%	3097
November	1st to 10th	Day	56% 4 15% 18% 7% 1	1584
	11th to 20th	Day	63% 5% 14% 13% 5%	1600
	21st to end	Day	57% 5% 17% 18% 3	1453
December	1st to 10th	Day	57% 8% 16% 13% 6%	2012
	11th to 20th	Day	64% 6% 18% 8% 4	2260
	21st to end	Day	45% 5% 13% 20% 13% 3	2992
January	1st to 10th	Night	59% 4 15% 18% 4	6766
	11th to 20th	Night	57% 4 14% 15% 9%	6780
	21st to end	Night	50% 7% 22% 17% 4	7218
February	1st to 10th	Night	56% 4 12% 19% 8%	2735
	11th to 20th	Night	47% 5% 14% 22% 11%	2533
	21st to end	Night	46% 5% 17% 23% 9%	2117
March	1st to 10th	Night	54% 5% 17% 19% 4	5374
	11th to 20th	Night	49% 7% 17% 20% 7%	5045
	21st to end	Night	49% 5% 11% 24% 11%	5199
April	1st to 10th	Night	39% 5% 14% 26% 14% 2	2000
	11th to 20th	Night	50% 5% 10% 21% 12% 2	1876
	21st to end	Night	47% 5% 12% 23% 12% 2	1613
May	1st to 10th	Night	44% 4 8% 24% 18% 3	3640
	11th to 20th	Night	51% 5% 10% 20% 13% 1	3618
	21st to end	Night	40% 4 10% 28% 16% 2	3372
June	1st to 10th	Night	38% 4 12% 32% 12% 2	1200
	11th to 20th	Night	50% 6% 13% 19% 11% 1	1200
	21st to end	Night	35% 5% 22% 27% 11%	1200
July	1st to 10th	Night	30% 8% 24% 32% 6%	2865
	11th to 20th	Night	30% 6% 17% 40% 7%	3138
	21st to end	Night	22% 5% 23% 38% 11% 1	3533
August	1st to 10th	Night	29% 5% 23% 30% 11% 1	2600
	11th to 20th	Night	27% 7% 23% 31% 11%	2683
	21st to end	Night	29% 6% 17% 35% 13%	3357
September	1st to 10th	Night	32% 4 14% 31% 14% 5%	2000
	11th to 20th	Night	36% 5% 17% 31% 10% 2	2000
	21st to end	Night	30% 4 13% 34% 18% 2	2274
October	1st to 10th	Night	36% 4 18% 35% 8%	3920
	11th to 20th	Night	33% 5% 14% 33% 15% 1	3925
	21st to end	Night	41% 4 19% 30% 6% 1	4702
November	1st to 10th	Night	57% 4 13% 18% 7%	2759
	11th to 20th	Night	58% 5% 17% 15% 4	2800
	21st to end	Night	54% 5% 18% 19% 3	2945
December	1st to 10th	Night	64% 6% 14% 12% 4	5156
	11th to 20th	Night	61% 7% 16% 12% 3	5931
	21st to end	Night	45% 3 11% 26% 12% 2	7964

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	14% 4 29% 29% 18% 7%	200
	11th to 20th	Day	13% 7% 29% 34% 17% 2	200
	21st to end	Day	14% 8% 31% 28% 17% 2	274
February	1st to 10th	Day	15% 8% 30% 34% 10% 3	300
	11th to 20th	Day	11% 5% 26% 39% 14% 5%	300
	21st to end	Day	8% 6% 29% 34% 20% 4	249
March	1st to 10th	Day	12% 9% 30% 33% 14% 2	300
	11th to 20th	Day	11% 10% 34% 29% 12% 4	476
	21st to end	Day	16% 7% 32% 29% 13% 2	550
April	1st to 10th	Day	13% 10% 33% 28% 11% 5%	500
	11th to 20th	Day	18% 14% 30% 26% 10% 2	492
	21st to end	Day	15% 8% 30% 30% 15% 2	686
May	1st to 10th	Day	16% 7% 25% 31% 17% 5%	703
	11th to 20th	Day	14% 9% 22% 32% 18% 6%	725
	21st to end	Day	16% 8% 21% 30% 21% 5%	789
June	1st to 10th	Day	14% 9% 27% 33% 13% 3	730
	11th to 20th	Day	22% 9% 25% 27% 13% 4	730
	21st to end	Day	14% 7% 18% 32% 22% 6%	730
July	1st to 10th	Day	10% 4 20% 34% 25% 8%	721
	11th to 20th	Day	9% 6% 24% 28% 23% 9%	718
	21st to end	Day	7% 4 23% 29% 27% 10%	794
August	1st to 10th	Day	9% 6% 20% 28% 27% 10%	726
	11th to 20th	Day	11% 5% 19% 35% 23% 8%	669
	21st to end	Day	13% 5% 22% 31% 23% 6%	583
September	1st to 10th	Day	12% 9% 27% 28% 19% 3	530
	11th to 20th	Day	16% 7% 28% 32% 14% 3	530
	21st to end	Day	14% 9% 28% 30% 17% 2	385
October	1st to 10th	Day	18% 6% 26% 30% 15% 5%	330
	11th to 20th	Day	13% 11% 29% 30% 15% 2	330
	21st to end	Day	11% 12% 39% 23% 12% 3	363
November	1st to 10th	Day	18% 6% 31% 30% 11% 3	306
	11th to 20th	Day	16% 9% 35% 32% 8% 2	300
	21st to end	Day	11% 7% 34% 33% 11% 4	300
December	1st to 10th	Day	10% 8% 22% 39% 16% 5%	219
	11th to 20th	Day	10% 6% 42% 31% 12% 1	200
	21st to end	Day	9% 3 26% 35% 21% 6%	220
January	1st to 10th	Night	11% 5% 34% 35% 13% 2	1000
	11th to 20th	Night	12% 7% 33% 36% 11% 1	1000
	21st to end	Night	13% 7% 34% 35% 10% 1	1100
February	1st to 10th	Night	12% 5% 27% 37% 17% 2	935
	11th to 20th	Night	10% 4 27% 40% 15% 3	784
	21st to end	Night	6% 4 25% 40% 22% 4	660
March	1st to 10th	Night	11% 4 29% 40% 15% 2	800
	11th to 20th	Night	10% 6% 31% 36% 14% 2	800
	21st to end	Night	13% 6% 27% 39% 13% 2	758
April	1st to 10th	Night	10% 7% 28% 39% 15% 2	600
	11th to 20th	Night	16% 7% 31% 34% 11% 1	593
	21st to end	Night	17% 7% 31% 33% 11% 1	600
May	1st to 10th	Night	15% 5% 29% 36% 16% 1	600
	11th to 20th	Night	12% 5% 30% 36% 16% 2	591
	21st to end	Night	18% 3 24% 37% 16% 3	471
June	1st to 10th	Night	14% 6% 28% 33% 17% 2	400
	11th to 20th	Night	23% 6% 20% 33% 18% 2	400
	21st to end	Night	14% 5% 16% 43% 21% 2	400
July	1st to 10th	Night	6% 3 21% 44% 24% 2	390
	11th to 20th	Night	12% 3 23% 41% 20% 1	388
	21st to end	Night	5% 4 21% 45% 23% 3	505
August	1st to 10th	Night	8% 4 21% 39% 26% 3	597
	11th to 20th	Night	9% 3 18% 40% 28% 2	594
	21st to end	Night	11% 4 24% 40% 20% 1	660
September	1st to 10th	Night	11% 4 25% 39% 20% 2	600
	11th to 20th	Night	14% 4 21% 42% 18% 1	600
	21st to end	Night	10% 6% 32% 37% 14% 1	729
October	1st to 10th	Night	17% 4 26% 38% 14% 1	800
	11th to 20th	Night	12% 5% 31% 37% 14% 2	815
	21st to end	Night	16% 8% 33% 32% 10%	1100
November	1st to 10th	Night	22% 5% 30% 35% 8% 1	986
	11th to 20th	Night	13% 7% 32% 33% 12% 2	1000
	21st to end	Night	13% 7% 33% 36% 9% 2	1000
December	1st to 10th	Night	11% 6% 29% 36% 16% 2	1000
	11th to 20th	Night	12% 7% 31% 37% 13% 1	1000
	21st to end	Night	9% 3 27% 39% 17% 4	1100

Page generated at 2025-10-31 00:02:37. Version ac07

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