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 2024-11-06.

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%	105501
	Night	8% 9% 3 9% 6% 5% 5% 4 6% 8% 37%	102106
Transparency	Day	44% 5% 17% 25% 9% 1	105246
	Night	44% 5% 16% 25% 9% 1	102007
Seeing	Day	13% 7% 26% 31% 17% 5%	15812
	Night	13% 5% 28% 37% 15% 2	25053

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% 15% 7% 14% 8% 7% 6% 4 6% 6% 21%	2201
	11th to 20th	Day	5% 9% 4 12% 9% 12% 9% 6% 7% 7% 21%	2199
	21st to end	Day	6% 10% 4 12% 7% 6% 5% 5% 6% 7% 32%	2607
February	1st to 10th	Day	8% 13% 5% 12% 7% 7% 7% 6% 6% 8% 22%	1596
	11th to 20th	Day	6% 13% 6% 12% 8% 6% 5% 6% 7% 6% 26%	1665
	21st to end	Day	5% 10% 5% 12% 10% 6% 8% 6% 6% 8% 24%	1439
March	1st to 10th	Day	7% 13% 6% 11% 8% 7% 7% 4 5% 6% 26%	3130
	11th to 20th	Day	6% 12% 4 12% 5% 4 5% 3 5% 8% 35%	3453
	21st to end	Day	7% 9% 3 9% 7% 6% 6% 5% 7% 8% 34%	4023
April	1st to 10th	Day	8% 11% 4 7% 6% 6% 5% 5% 6% 7% 34%	2280
	11th to 20th	Day	12% 13% 4 9% 5% 5% 5% 4 6% 6% 31%	2346
	21st to end	Day	13% 10% 3 9% 5% 6% 5% 4 6% 8% 33%	2646
May	1st to 10th	Day	19% 11% 3 7% 3 4 4 3 5% 6% 34%	4430
	11th to 20th	Day	9% 7% 3 9% 7% 5% 6% 5% 7% 8% 34%	4388
	21st to end	Day	13% 10% 3 8% 6% 6% 5% 4 6% 7% 30%	5213
June	1st to 10th	Day	13% 7% 3 7% 5% 5% 4 5% 7% 9% 35%	3040
	11th to 20th	Day	21% 8% 3 7% 6% 4 5% 5% 7% 7% 28%	3040
	21st to end	Day	12% 6% 3 6% 6% 6% 5% 5% 8% 9% 36%	3040
July	1st to 10th	Day	7% 4 1 5% 4 5% 6% 5% 7% 10% 45%	4934
	11th to 20th	Day	7% 4 2 5% 4 5% 4 5% 7% 10% 48%	4740
	21st to end	Day	5% 3 1 4 4 3 4 4 6% 10% 56%	5028
August	1st to 10th	Day	10% 5% 2 6% 5% 4 5% 4 6% 8% 46%	4412
	11th to 20th	Day	7% 5% 2 5% 4 4 4 4 6% 10% 48%	4261
	21st to end	Day	12% 5% 1 4 3 3 4 3 5% 8% 52%	4412
September	1st to 10th	Day	10% 5% 2 7% 4 4 3 3 7% 8% 48%	2280
	11th to 20th	Day	13% 6% 2 7% 4 4 4 3 6% 8% 41%	2280
	21st to end	Day	10% 5% 2 5% 4 4 4 3 5% 8% 51%	2019
October	1st to 10th	Day	10% 9% 2 5% 3 3 4 3 5% 9% 47%	3170
	11th to 20th	Day	7% 6% 2 6% 4 4 5% 4 9% 13% 39%	3092
	21st to end	Day	6% 9% 4 10% 5% 6% 7% 4 7% 7% 36%	3001
November	1st to 10th	Day	15% 15% 6% 10% 5% 3 4 3 4 5% 30%	1528
	11th to 20th	Day	8% 15% 5% 14% 7% 7% 5% 4 4 6% 24%	1520
	21st to end	Day	8% 13% 6% 11% 7% 6% 6% 5% 5% 6% 27%	1381
December	1st to 10th	Day	7% 13% 4 12% 8% 6% 7% 4 6% 8% 24%	1178
	11th to 20th	Day	9% 11% 5% 11% 9% 6% 8% 3 4 6% 29%	1439
	21st to end	Day	3 10% 4 10% 5% 5% 6% 4 6% 6% 42%	2090
January	1st to 10th	Night	5% 13% 5% 14% 8% 7% 6% 5% 7% 7% 21%	4726
	11th to 20th	Night	4 8% 4 15% 11% 11% 9% 5% 6% 7% 21%	4699
	21st to end	Night	7% 12% 4 11% 7% 5% 5% 4 6% 8% 31%	5052
February	1st to 10th	Night	7% 11% 5% 13% 8% 6% 6% 5% 7% 7% 25%	2599
	11th to 20th	Night	5% 11% 4 11% 6% 5% 6% 4 7% 7% 32%	2402
	21st to end	Night	3 9% 4 10% 8% 6% 7% 5% 7% 8% 33%	2015
March	1st to 10th	Night	7% 11% 5% 13% 6% 7% 7% 5% 7% 7% 24%	3734
	11th to 20th	Night	6% 9% 4 10% 6% 6% 6% 5% 7% 10% 33%	3522
	21st to end	Night	7% 8% 3 9% 6% 5% 5% 5% 7% 10% 35%	3622
April	1st to 10th	Night	6% 9% 3 7% 6% 5% 4 4 6% 8% 42%	1900
	11th to 20th	Night	11% 13% 3 8% 6% 6% 6% 4 6% 7% 31%	1781
	21st to end	Night	13% 10% 3 8% 6% 5% 4 3 6% 7% 36%	1533
May	1st to 10th	Night	17% 10% 4 8% 5% 4 4 4 5% 6% 33%	2540
	11th to 20th	Night	11% 8% 3 7% 5% 6% 6% 5% 6% 8% 36%	2518
	21st to end	Night	15% 8% 3 7% 5% 5% 4 4 5% 8% 35%	2344
June	1st to 10th	Night	11% 6% 1 7% 5% 4 5% 4 8% 8% 39%	1140
	11th to 20th	Night	18% 7% 3 9% 4 5% 4 5% 5% 7% 33%	1140
	21st to end	Night	11% 4 1 6% 4 4 4 4 7% 9% 45%	1140
July	1st to 10th	Night	7% 4 1 5% 4 5% 5% 5% 8% 11% 44%	2022
	11th to 20th	Night	6% 3 1 4 4 4 4 5% 7% 9% 54%	2220
	21st to end	Night	3 2 1 3 2 3 3 3 6% 8% 66%	2526
August	1st to 10th	Night	7% 4 2 5% 4 3 4 4 6% 8% 53%	2528
	11th to 20th	Night	5% 3 2 5% 4 5% 6% 5% 8% 11% 47%	2577
	21st to end	Night	8% 5% 2 5% 3 3 4 4 5% 7% 53%	3255
September	1st to 10th	Night	9% 4 1 6% 4 4 4 4 6% 8% 49%	1900
	11th to 20th	Night	12% 6% 2 6% 3 4 5% 3 6% 9% 44%	1900
	21st to end	Night	8% 6% 2 5% 4 3 4 3 5% 7% 52%	2160
October	1st to 10th	Night	10% 7% 2 5% 4 4 4 3 5% 7% 49%	3800
	11th to 20th	Night	6% 6% 2 7% 4 5% 4 4 5% 8% 50%	3804
	21st to end	Night	8% 9% 3 9% 4 4 5% 4 5% 8% 42%	4556
November	1st to 10th	Night	15% 14% 5% 8% 6% 5% 5% 4 5% 7% 27%	2673
	11th to 20th	Night	7% 14% 5% 13% 7% 6% 5% 3 6% 6% 27%	2660
	21st to end	Night	7% 13% 5% 12% 7% 5% 5% 3 5% 8% 29%	2797
December	1st to 10th	Night	6% 12% 5% 11% 9% 7% 6% 4 5% 7% 28%	3002
	11th to 20th	Night	7% 13% 6% 13% 7% 6% 7% 5% 6% 7% 22%	3753
	21st to end	Night	3 7% 3 7% 5% 5% 5% 4 6% 6% 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	63% 3 12% 14% 7%	2201
	11th to 20th	Day	61% 4 13% 16% 5% 1	2220
	21st to end	Day	51% 5% 18% 21% 6%	2607
February	1st to 10th	Day	58% 6% 12% 17% 7%	1596
	11th to 20th	Day	54% 4 12% 21% 8% 1	1674
	21st to end	Day	57% 5% 11% 19% 8%	1439
March	1st to 10th	Day	59% 3 16% 15% 7%	3130
	11th to 20th	Day	49% 7% 20% 20% 5%	3454
	21st to end	Day	46% 5% 12% 24% 12%	4023
April	1st to 10th	Day	46% 6% 13% 24% 11%	2280
	11th to 20th	Day	53% 4 12% 18% 10% 1	2346
	21st to end	Day	49% 4 14% 24% 8% 1	2646
May	1st to 10th	Day	50% 3 13% 23% 10% 1	4430
	11th to 20th	Day	45% 6% 10% 26% 12% 1	4392
	21st to end	Day	50% 5% 13% 21% 11% 1	5213
June	1st to 10th	Day	45% 4 15% 24% 11% 1	3040
	11th to 20th	Day	53% 5% 13% 21% 7% 1	3040
	21st to end	Day	41% 6% 19% 25% 8%	3040
July	1st to 10th	Day	29% 8% 26% 30% 6%	4858
	11th to 20th	Day	30% 6% 18% 39% 7%	4659
	21st to end	Day	23% 6% 20% 39% 11%	4869
August	1st to 10th	Day	35% 6% 22% 29% 8%	4396
	11th to 20th	Day	30% 6% 21% 37% 6%	4303
	21st to end	Day	32% 4 21% 35% 8%	4411
September	1st to 10th	Day	34% 4 17% 29% 13% 3	2280
	11th to 20th	Day	41% 4 19% 26% 8% 1	2280
	21st to end	Day	32% 4 16% 34% 13% 2	2019
October	1st to 10th	Day	36% 4 26% 26% 9%	3170
	11th to 20th	Day	36% 4 20% 33% 6%	3092
	21st to end	Day	45% 5% 20% 26% 4	3001
November	1st to 10th	Day	57% 4 14% 17% 7%	1528
	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	60% 4 16% 17% 3	4726
	11th to 20th	Night	63% 3 15% 14% 5%	4740
	21st to end	Night	51% 6% 18% 19% 5%	5052
February	1st to 10th	Night	56% 4 13% 20% 7%	2599
	11th to 20th	Night	48% 5% 14% 21% 11%	2403
	21st to end	Night	47% 5% 16% 23% 9%	2015
March	1st to 10th	Night	56% 4 15% 22% 4	3734
	11th to 20th	Night	46% 6% 21% 21% 7%	3522
	21st to end	Night	43% 4 12% 27% 14%	3622
April	1st to 10th	Night	38% 6% 14% 26% 14% 2	1900
	11th to 20th	Night	51% 5% 10% 20% 12% 2	1781
	21st to end	Night	47% 5% 12% 23% 12% 2	1533
May	1st to 10th	Night	52% 4 10% 25% 9% 1	2540
	11th to 20th	Night	45% 5% 8% 23% 18% 1	2518
	21st to end	Night	47% 5% 12% 27% 9% 1	2344
June	1st to 10th	Night	39% 4 13% 31% 11% 2	1140
	11th to 20th	Night	50% 6% 12% 19% 12% 1	1140
	21st to end	Night	33% 5% 22% 27% 11%	1140
July	1st to 10th	Night	28% 10% 25% 31% 6%	1989
	11th to 20th	Night	24% 7% 16% 43% 10%	2178
	21st to end	Night	16% 5% 20% 45% 12% 2	2446
August	1st to 10th	Night	29% 5% 23% 31% 12% 1	2520
	11th to 20th	Night	27% 8% 23% 31% 11%	2601
	21st to end	Night	29% 6% 16% 35% 13%	3255
September	1st to 10th	Night	32% 4 15% 30% 15% 5%	1900
	11th to 20th	Night	36% 4 16% 31% 11% 2	1900
	21st to end	Night	31% 4 13% 32% 17% 2	2160
October	1st to 10th	Night	36% 3 18% 35% 7%	3800
	11th to 20th	Night	33% 5% 14% 33% 15% 1	3804
	21st to end	Night	41% 4 19% 30% 5% 1	4556
November	1st to 10th	Night	58% 4 13% 18% 7%	2673
	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	14% 6% 24% 36% 18% 2	180
	21st to end	Day	13% 7% 28% 30% 19% 2	246
February	1st to 10th	Day	16% 7% 30% 34% 11% 3	270
	11th to 20th	Day	13% 6% 26% 38% 13% 4	270
	21st to end	Day	8% 4 28% 34% 22% 4	225
March	1st to 10th	Day	14% 9% 29% 32% 15% 2	270
	11th to 20th	Day	11% 9% 35% 29% 11% 4	437
	21st to end	Day	16% 7% 33% 30% 13% 2	506
April	1st to 10th	Day	13% 11% 34% 25% 11% 5%	460
	11th to 20th	Day	20% 13% 29% 26% 10% 2	452
	21st to end	Day	16% 8% 31% 29% 14% 2	636
May	1st to 10th	Day	16% 6% 25% 31% 17% 5%	653
	11th to 20th	Day	12% 8% 21% 34% 19% 6%	675
	21st to end	Day	16% 8% 22% 29% 20% 5%	734
June	1st to 10th	Day	14% 8% 26% 35% 13% 3	680
	11th to 20th	Day	23% 9% 25% 26% 13% 4	680
	21st to end	Day	13% 7% 18% 33% 22% 7%	680
July	1st to 10th	Day	10% 3 20% 34% 25% 8%	671
	11th to 20th	Day	9% 6% 24% 28% 23% 10%	668
	21st to end	Day	7% 4 24% 28% 26% 10%	739
August	1st to 10th	Day	9% 5% 20% 29% 27% 10%	676
	11th to 20th	Day	11% 5% 18% 34% 24% 8%	622
	21st to end	Day	14% 5% 23% 31% 22% 5%	539
September	1st to 10th	Day	13% 10% 28% 28% 19% 3	490
	11th to 20th	Day	17% 7% 29% 31% 13% 3	490
	21st to end	Day	14% 9% 28% 29% 18% 2	352
October	1st to 10th	Day	18% 5% 26% 29% 16% 5%	300
	11th to 20th	Day	12% 11% 29% 30% 16% 2	300
	21st to end	Day	11% 11% 39% 24% 12% 3	330
November	1st to 10th	Day	19% 4 29% 32% 12% 4	285
	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	12% 6% 33% 36% 12% 1	950
	21st to end	Night	13% 6% 32% 37% 11% 1	1045
February	1st to 10th	Night	12% 4 27% 38% 17% 2	889
	11th to 20th	Night	11% 5% 28% 39% 15% 3	744
	21st to end	Night	6% 3 24% 41% 23% 4	628
March	1st to 10th	Night	11% 4 28% 40% 15% 2	760
	11th to 20th	Night	10% 6% 31% 37% 14% 2	760
	21st to end	Night	13% 6% 28% 38% 13% 2	720
April	1st to 10th	Night	9% 7% 29% 39% 14% 2	570
	11th to 20th	Night	17% 7% 30% 33% 11% 1	563
	21st to end	Night	18% 7% 31% 33% 11% 1	570
May	1st to 10th	Night	15% 5% 29% 35% 16% 1	570
	11th to 20th	Night	11% 4 29% 38% 16% 2	561
	21st to end	Night	18% 3 24% 36% 17% 3	447
June	1st to 10th	Night	14% 5% 27% 33% 17% 2	380
	11th to 20th	Night	23% 6% 20% 31% 18% 2	380
	21st to end	Night	13% 5% 16% 43% 22% 2	380
July	1st to 10th	Night	6% 3 20% 44% 25% 2	370
	11th to 20th	Night	12% 3 24% 41% 20% 1	368
	21st to end	Night	5% 4 22% 44% 23% 3	479
August	1st to 10th	Night	7% 4 21% 39% 26% 3	567
	11th to 20th	Night	8% 3 17% 40% 30% 2	564
	21st to end	Night	11% 3 25% 40% 20% 1	627
September	1st to 10th	Night	11% 4 25% 39% 20% 1	570
	11th to 20th	Night	15% 5% 21% 41% 17% 1	570
	21st to end	Night	11% 7% 32% 36% 14% 1	692
October	1st to 10th	Night	18% 4 26% 36% 14% 1	760
	11th to 20th	Night	11% 5% 31% 37% 15% 2	774
	21st to end	Night	16% 8% 33% 32% 11%	1045
November	1st to 10th	Night	22% 5% 29% 35% 9% 1	955
	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 2024-11-03 12:19:00. Version ac07

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