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 2024-01-16.

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% 8% 4 7% 6% 4 5% 5% 6% 8% 36%	74524
	Night	8% 8% 4 8% 7% 4 5% 5% 6% 8% 37%	75266
Transparency	Day	46% 5% 16% 24% 9% 1	74206
	Night	45% 5% 15% 24% 10% 1	75102
Seeing	Day	13% 7% 26% 31% 17% 5%	14624
	Night	13% 5% 28% 37% 15% 2	24079

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	8% 13% 7% 10% 8% 5% 5% 6% 7% 7% 24%	1324
	11th to 20th	Day	8% 12% 6% 11% 7% 4 8% 5% 6% 8% 25%	1295
	21st to end	Day	6% 11% 6% 14% 10% 5% 7% 6% 6% 7% 20%	1481
February	1st to 10th	Day	7% 11% 6% 10% 9% 6% 8% 7% 6% 9% 22%	1512
	11th to 20th	Day	6% 13% 7% 10% 9% 4 6% 6% 7% 7% 25%	1575
	21st to end	Day	6% 9% 5% 12% 11% 4 9% 7% 6% 8% 24%	1356
March	1st to 10th	Day	8% 13% 7% 10% 10% 6% 8% 6% 5% 7% 21%	1800
	11th to 20th	Day	8% 13% 5% 9% 6% 3 6% 5% 5% 8% 32%	1957
	21st to end	Day	9% 12% 4 8% 9% 4 5% 5% 5% 8% 31%	2286
April	1st to 10th	Day	8% 10% 5% 6% 7% 5% 6% 6% 6% 7% 35%	2160
	11th to 20th	Day	12% 11% 5% 8% 6% 4 5% 5% 6% 6% 31%	2221
	21st to end	Day	14% 10% 3 7% 6% 4 5% 5% 5% 8% 33%	2506
May	1st to 10th	Day	13% 6% 3 6% 5% 3 6% 6% 7% 8% 37%	2520
	11th to 20th	Day	8% 6% 3 6% 7% 3 5% 6% 6% 7% 41%	2478
	21st to end	Day	17% 7% 3 5% 6% 4 5% 5% 6% 7% 34%	2939
June	1st to 10th	Day	13% 6% 3 6% 6% 4 5% 6% 6% 9% 36%	2880
	11th to 20th	Day	21% 8% 4 6% 6% 3 5% 5% 6% 7% 28%	2880
	21st to end	Day	11% 5% 3 6% 6% 4 6% 6% 7% 9% 37%	2880
July	1st to 10th	Day	7% 4 2 5% 5% 3 6% 7% 7% 10% 45%	2810
	11th to 20th	Day	10% 4 2 5% 5% 4 5% 6% 7% 9% 44%	2700
	21st to end	Day	7% 2 2 4 5% 3 5% 5% 6% 10% 52%	2877
August	1st to 10th	Day	9% 4 2 5% 6% 3 6% 7% 7% 9% 43%	2507
	11th to 20th	Day	10% 6% 2 5% 5% 3 4 6% 6% 10% 44%	2437
	21st to end	Day	12% 5% 2 4 4 2 5% 4 5% 8% 48%	2517
September	1st to 10th	Day	11% 5% 2 6% 6% 3 3 4 7% 8% 46%	2160
	11th to 20th	Day	13% 6% 2 6% 5% 3 4 4 6% 8% 43%	2160
	21st to end	Day	11% 4 2 4 4 3 5% 4 5% 9% 51%	1914
October	1st to 10th	Day	15% 10% 2 5% 5% 3 4 4 4 8% 41%	1800
	11th to 20th	Day	12% 8% 4 6% 5% 3 4 4 5% 7% 41%	1768
	21st to end	Day	9% 12% 4 10% 6% 4 6% 6% 6% 7% 31%	1728
November	1st to 10th	Day	15% 14% 6% 10% 6% 2 4 4 4 5% 30%	1488
	11th to 20th	Day	9% 14% 6% 13% 9% 5% 6% 5% 4 6% 25%	1520
	21st to end	Day	8% 12% 7% 10% 7% 4 7% 6% 5% 6% 27%	1381
December	1st to 10th	Day	8% 12% 5% 11% 9% 5% 8% 5% 5% 8% 25%	1178
	11th to 20th	Day	9% 10% 6% 10% 10% 5% 7% 5% 4 6% 29%	1439
	21st to end	Day	3 9% 4 9% 6% 3 6% 6% 6% 6% 42%	2090
January	1st to 10th	Night	7% 10% 4 10% 10% 6% 7% 8% 7% 7% 25%	2836
	11th to 20th	Night	7% 11% 6% 10% 8% 5% 7% 6% 5% 7% 28%	2776
	21st to end	Night	8% 12% 6% 11% 11% 5% 7% 6% 6% 8% 21%	2873
February	1st to 10th	Night	6% 9% 5% 12% 9% 4 7% 7% 7% 8% 25%	2462
	11th to 20th	Night	6% 10% 5% 10% 7% 4 7% 6% 7% 8% 30%	2272
	21st to end	Night	3 8% 6% 9% 9% 4 7% 7% 7% 9% 33%	1900
March	1st to 10th	Night	8% 8% 5% 11% 7% 4 6% 6% 6% 7% 30%	2160
	11th to 20th	Night	7% 9% 4 8% 6% 4 5% 5% 7% 8% 35%	1999
	21st to end	Night	9% 10% 4 10% 7% 4 5% 6% 6% 8% 33%	2069
April	1st to 10th	Night	7% 8% 3 6% 6% 4 5% 5% 6% 8% 42%	1800
	11th to 20th	Night	12% 11% 3 7% 7% 5% 7% 5% 5% 7% 32%	1687
	21st to end	Night	14% 9% 4 7% 6% 4 5% 4 6% 7% 36%	1453
May	1st to 10th	Night	11% 6% 2 7% 4 3 5% 5% 6% 7% 43%	1440
	11th to 20th	Night	9% 6% 2 4 5% 3 5% 5% 6% 9% 45%	1418
	21st to end	Night	16% 5% 3 5% 5% 4 5% 5% 5% 7% 40%	1330
June	1st to 10th	Night	11% 5% 2 6% 6% 3 5% 6% 8% 8% 40%	1080
	11th to 20th	Night	19% 7% 3 6% 6% 4 5% 5% 5% 8% 32%	1080
	21st to end	Night	11% 4 1 6% 4 3 5% 5% 7% 9% 45%	1080
July	1st to 10th	Night	5% 3 2 6% 4 3 5% 6% 8% 10% 47%	1146
	11th to 20th	Night	9% 4 2 4 4 4 4 6% 6% 9% 48%	1260
	21st to end	Night	5% 2 2 3 3 3 3 4 5% 8% 63%	1438
August	1st to 10th	Night	5% 3 1 3 4 3 4 5% 7% 8% 55%	1432
	11th to 20th	Night	7% 4 2 3 3 3 4 6% 6% 11% 50%	1463
	21st to end	Night	9% 5% 2 4 4 3 4 4 5% 8% 51%	1839
September	1st to 10th	Night	10% 4 2 5% 5% 3 4 5% 6% 8% 47%	1800
	11th to 20th	Night	12% 5% 2 5% 4 2 5% 4 6% 9% 46%	1800
	21st to end	Night	8% 6% 2 4 4 2 3 5% 5% 7% 53%	2045
October	1st to 10th	Night	13% 8% 3 5% 5% 2 5% 5% 5% 8% 41%	2160
	11th to 20th	Night	8% 7% 3 6% 5% 4 3 4 5% 8% 47%	2173
	21st to end	Night	10% 11% 4 11% 6% 3 5% 4 4 7% 35%	2627
November	1st to 10th	Night	15% 13% 6% 7% 6% 4 5% 5% 4 7% 27%	2590
	11th to 20th	Night	7% 13% 5% 11% 9% 5% 6% 5% 6% 6% 27%	2660
	21st to end	Night	8% 11% 6% 11% 7% 4 5% 4 5% 9% 29%	2797
December	1st to 10th	Night	7% 11% 6% 10% 9% 5% 6% 5% 5% 7% 28%	3002
	11th to 20th	Night	8% 12% 6% 11% 9% 4 7% 7% 6% 7% 22%	3753
	21st to end	Night	4 6% 3 7% 6% 3 5% 5% 5% 7% 49%	5566

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	59% 4 14% 16% 7%	1324
	11th to 20th	Day	57% 5% 16% 16% 6% 1	1295
	21st to end	Day	61% 6% 10% 15% 8%	1481
February	1st to 10th	Day	57% 6% 13% 17% 7%	1512
	11th to 20th	Day	56% 4 12% 20% 7% 1	1584
	21st to end	Day	58% 4 10% 19% 9%	1356
March	1st to 10th	Day	62% 4 12% 17% 4	1800
	11th to 20th	Day	51% 5% 15% 22% 7%	1958
	21st to end	Day	51% 6% 18% 19% 6%	2286
April	1st to 10th	Day	46% 6% 12% 24% 11%	2160
	11th to 20th	Day	53% 4 13% 18% 10% 1	2221
	21st to end	Day	50% 4 14% 23% 8% 1	2506
May	1st to 10th	Day	43% 4 12% 27% 12% 1	2520
	11th to 20th	Day	40% 6% 11% 29% 12% 2	2482
	21st to end	Day	48% 4 13% 20% 14% 1	2939
June	1st to 10th	Day	45% 4 15% 25% 10% 1	2880
	11th to 20th	Day	54% 5% 13% 20% 7% 1	2880
	21st to end	Day	42% 6% 19% 24% 8%	2880
July	1st to 10th	Day	31% 7% 23% 31% 8%	2734
	11th to 20th	Day	36% 6% 21% 29% 7%	2619
	21st to end	Day	29% 5% 24% 34% 8%	2717
August	1st to 10th	Day	35% 6% 24% 25% 10%	2491
	11th to 20th	Day	34% 5% 24% 29% 6% 1	2437
	21st to end	Day	36% 4 17% 35% 9%	2517
September	1st to 10th	Day	35% 4 18% 29% 12% 2	2160
	11th to 20th	Day	40% 4 19% 27% 9% 1	2160
	21st to end	Day	32% 4 16% 33% 13% 2	1914
October	1st to 10th	Day	43% 4 20% 25% 8%	1800
	11th to 20th	Day	43% 3 16% 29% 8% 1	1768
	21st to end	Day	52% 4 16% 22% 5%	1728
November	1st to 10th	Day	57% 4 14% 17% 8%	1488
	11th to 20th	Day	62% 5% 15% 13% 5%	1520
	21st to end	Day	57% 5% 17% 17% 4	1381
December	1st to 10th	Day	58% 5% 15% 15% 7%	1178
	11th to 20th	Day	58% 6% 20% 10% 6%	1440
	21st to end	Day	41% 4 15% 18% 17% 4	2090
January	1st to 10th	Night	56% 5% 16% 18% 6%	2836
	11th to 20th	Night	56% 4 17% 17% 5% 1	2776
	21st to end	Night	61% 6% 12% 13% 8%	2873
February	1st to 10th	Night	55% 5% 13% 20% 7%	2462
	11th to 20th	Night	50% 5% 15% 20% 10%	2273
	21st to end	Night	46% 5% 16% 24% 10%	1900
March	1st to 10th	Night	51% 4 16% 22% 6%	2160
	11th to 20th	Night	44% 6% 17% 23% 9% 1	1999
	21st to end	Night	49% 5% 15% 21% 9%	2069
April	1st to 10th	Night	39% 6% 13% 27% 14% 2	1800
	11th to 20th	Night	51% 5% 10% 20% 12% 2	1687
	21st to end	Night	47% 4 12% 23% 12% 2	1453
May	1st to 10th	Night	39% 5% 9% 30% 16% 1	1440
	11th to 20th	Night	36% 5% 11% 28% 19% 2	1418
	21st to end	Night	42% 5% 13% 23% 15% 2	1330
June	1st to 10th	Night	39% 5% 13% 30% 11% 2	1080
	11th to 20th	Night	50% 6% 13% 18% 11% 1	1080
	21st to end	Night	34% 5% 23% 27% 11%	1080
July	1st to 10th	Night	28% 6% 23% 34% 8% 1	1113
	11th to 20th	Night	32% 6% 21% 31% 10%	1218
	21st to end	Night	22% 3 25% 39% 10% 1	1358
August	1st to 10th	Night	26% 5% 25% 31% 12% 1	1424
	11th to 20th	Night	26% 6% 21% 34% 11% 1	1463
	21st to end	Night	32% 4 13% 36% 15% 1	1839
September	1st to 10th	Night	33% 4 15% 29% 14% 5%	1800
	11th to 20th	Night	35% 4 17% 32% 11% 2	1800
	21st to end	Night	31% 4 13% 32% 17% 2	2045
October	1st to 10th	Night	43% 4 16% 28% 9%	2160
	11th to 20th	Night	37% 4 16% 29% 13% 1	2173
	21st to end	Night	50% 3 14% 24% 7% 1	2627
November	1st to 10th	Night	58% 4 13% 18% 7%	2590
	11th to 20th	Night	57% 5% 18% 16% 4	2660
	21st to end	Night	54% 6% 19% 18% 4	2797
December	1st to 10th	Night	57% 4 15% 18% 6% 1	3002
	11th to 20th	Night	59% 7% 15% 14% 4	3751
	21st to end	Night	35% 3 14% 28% 16% 3	5566

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% 3 29% 28% 17% 7%	180
	11th to 20th	Day	15% 8% 21% 35% 18% 2	170
	21st to end	Day	14% 8% 30% 28% 18% 3	219
February	1st to 10th	Day	13% 6% 31% 35% 11% 3	240
	11th to 20th	Day	14% 5% 27% 40% 10% 4	240
	21st to end	Day	8% 3 27% 36% 21% 5%	198
March	1st to 10th	Day	13% 7% 31% 33% 15% 2	240
	11th to 20th	Day	11% 9% 34% 30% 12% 4	398
	21st to end	Day	17% 7% 32% 30% 12% 2	462
April	1st to 10th	Day	13% 11% 35% 26% 10% 5%	420
	11th to 20th	Day	18% 13% 30% 26% 10% 3	412
	21st to end	Day	17% 9% 31% 27% 14% 2	586
May	1st to 10th	Day	15% 6% 24% 32% 18% 5%	603
	11th to 20th	Day	12% 8% 21% 34% 19% 6%	625
	21st to end	Day	16% 8% 22% 28% 21% 6%	679
June	1st to 10th	Day	12% 8% 26% 36% 14% 4	630
	11th to 20th	Day	23% 9% 23% 27% 13% 4	630
	21st to end	Day	12% 7% 18% 33% 23% 7%	630
July	1st to 10th	Day	10% 4 21% 36% 24% 6%	621
	11th to 20th	Day	9% 6% 25% 28% 22% 9%	618
	21st to end	Day	7% 4 25% 28% 25% 11%	684
August	1st to 10th	Day	9% 5% 19% 29% 27% 10%	626
	11th to 20th	Day	11% 5% 18% 34% 23% 8%	575
	21st to end	Day	14% 4 22% 32% 23% 5%	495
September	1st to 10th	Day	14% 10% 29% 28% 17% 2	450
	11th to 20th	Day	16% 7% 28% 32% 14% 3	450
	21st to end	Day	15% 8% 26% 30% 19% 3	320
October	1st to 10th	Day	19% 5% 24% 29% 17% 6%	270
	11th to 20th	Day	13% 10% 28% 30% 15% 3	270
	21st to end	Day	12% 11% 37% 25% 13% 3	297
November	1st to 10th	Day	19% 4 30% 31% 13% 4	270
	11th to 20th	Day	14% 9% 35% 33% 8% 2	270
	21st to end	Day	11% 7% 35% 33% 10% 4	270
December	1st to 10th	Day	10% 6% 20% 42% 16% 6%	198
	11th to 20th	Day	10% 6% 42% 29% 12% 1	180
	21st to end	Day	10% 3 27% 33% 21% 7%	198
January	1st to 10th	Night	11% 5% 33% 35% 14% 2	950
	11th to 20th	Night	13% 6% 32% 37% 12% 1	926
	21st to end	Night	13% 7% 32% 36% 10% 1	990
February	1st to 10th	Night	11% 4 27% 39% 18% 2	842
	11th to 20th	Night	12% 5% 28% 38% 14% 3	704
	21st to end	Night	5% 3 23% 41% 24% 4	592
March	1st to 10th	Night	11% 3 28% 40% 16% 2	720
	11th to 20th	Night	10% 6% 31% 37% 14% 2	720
	21st to end	Night	13% 6% 27% 38% 13% 2	683
April	1st to 10th	Night	10% 7% 28% 39% 14% 2	540
	11th to 20th	Night	17% 7% 30% 33% 12% 1	533
	21st to end	Night	18% 7% 30% 33% 11% 1	540
May	1st to 10th	Night	14% 5% 28% 36% 16% 1	540
	11th to 20th	Night	11% 5% 28% 38% 17% 2	531
	21st to end	Night	18% 2 24% 35% 17% 3	424
June	1st to 10th	Night	14% 5% 26% 34% 18% 3	360
	11th to 20th	Night	24% 6% 19% 31% 19% 2	360
	21st to end	Night	13% 4 16% 43% 23% 2	360
July	1st to 10th	Night	6% 3 21% 45% 23% 2	350
	11th to 20th	Night	12% 3 25% 41% 18% 1	348
	21st to end	Night	5% 3 23% 43% 23% 3	453
August	1st to 10th	Night	7% 3 21% 39% 26% 3	537
	11th to 20th	Night	9% 3 17% 40% 29% 2	534
	21st to end	Night	12% 3 23% 41% 20% 1	594
September	1st to 10th	Night	12% 4 25% 38% 19% 1	540
	11th to 20th	Night	14% 4 21% 41% 18% 1	540
	21st to end	Night	11% 7% 31% 36% 14% 1	655
October	1st to 10th	Night	18% 4 26% 37% 14% 1	720
	11th to 20th	Night	12% 4 29% 37% 15% 2	733
	21st to end	Night	16% 7% 33% 32% 11% 1	990
November	1st to 10th	Night	22% 5% 30% 34% 8% 1	925
	11th to 20th	Night	13% 7% 32% 33% 13% 2	950
	21st to end	Night	13% 7% 34% 35% 9% 2	950
December	1st to 10th	Night	11% 5% 29% 36% 17% 2	950
	11th to 20th	Night	13% 7% 30% 36% 13% 1	950
	21st to end	Night	10% 3 27% 39% 17% 4	1045

Page generated at 2024-01-13 00:38:15. Version ac07

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