Toronto(KS)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Toronto(KS) clear sky chart from 2005-11-06 to 2025-03-12.

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	11% 7% 2 6% 4 4 4 3 5% 7% 48%	109540
	Night	10% 6% 2 5% 4 3 4 3 5% 6% 52%	109693
Transparency	Day	35% 5% 11% 26% 19% 4	113217
	Night	32% 5% 11% 27% 21% 5%	114143
Seeing	Day	14% 9% 28% 28% 17% 4	15962
	Night	13% 9% 32% 33% 12% 1	26004

By Month

Percentage Cloud Cover SE (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	15% 8% 2 7% 5% 5% 4 3 4 6% 41%	4077
	11th to 20th	Day	7% 9% 3 8% 6% 6% 4 3 4 6% 44%	4080
	21st to end	Day	12% 11% 4 6% 4 3 4 2 4 5% 46%	4488
February	1st to 10th	Day	15% 9% 4 7% 4 4 3 2 5% 6% 42%	1800
	11th to 20th	Day	11% 8% 3 9% 4 4 4 3 4 6% 45%	1853
	21st to end	Day	10% 8% 2 7% 6% 4 4 4 6% 6% 44%	1668
March	1st to 10th	Day	13% 8% 3 5% 3 3 2 2 3 6% 52%	3546
	11th to 20th	Day	11% 5% 1 4 2 3 3 3 5% 7% 56%	3491
	21st to end	Day	14% 10% 4 8% 4 4 4 3 5% 6% 39%	3814
April	1st to 10th	Day	11% 7% 2 6% 4 3 4 3 5% 7% 48%	2118
	11th to 20th	Day	15% 7% 3 7% 4 5% 3 3 4 5% 44%	2264
	21st to end	Day	19% 8% 2 6% 4 3 5% 3 5% 5% 40%	2470
May	1st to 10th	Day	19% 10% 3 7% 5% 4 3 3 4 5% 37%	4082
	11th to 20th	Day	12% 6% 3 6% 4 4 4 3 6% 7% 44%	4082
	21st to end	Day	13% 7% 2 7% 4 5% 4 4 6% 7% 41%	4477
June	1st to 10th	Day	6% 4 2 5% 4 4 5% 4 6% 10% 50%	2470
	11th to 20th	Day	8% 4 1 4 4 4 4 4 6% 8% 52%	2470
	21st to end	Day	6% 4 1 4 3 3 4 4 6% 8% 58%	2470
July	1st to 10th	Day	10% 6% 2 7% 4 5% 5% 4 7% 8% 42%	4120
	11th to 20th	Day	6% 3 2 5% 3 4 5% 4 6% 10% 52%	4120
	21st to end	Day	6% 4 2 6% 5% 5% 6% 5% 8% 10% 42%	4465
August	1st to 10th	Day	5% 4 2 5% 4 4 4 3 6% 8% 54%	4104
	11th to 20th	Day	7% 5% 2 7% 5% 5% 5% 4 6% 7% 49%	4041
	21st to end	Day	5% 3 1 4 3 3 4 4 6% 8% 59%	4349
September	1st to 10th	Day	13% 4 2 4 3 3 3 3 4 6% 54%	2169
	11th to 20th	Day	11% 4 2 5% 3 3 4 3 5% 8% 51%	2090
	21st to end	Day	10% 4 2 5% 3 4 3 2 4 6% 57%	2090
October	1st to 10th	Day	9% 6% 2 6% 4 3 3 3 5% 5% 53%	1954
	11th to 20th	Day	10% 4 1 3 2 3 3 2 4 6% 60%	1900
	21st to end	Day	16% 6% 2 4 3 3 3 2 5% 5% 52%	2090
November	1st to 10th	Day	10% 6% 2 4 2 2 3 2 4 6% 59%	1909
	11th to 20th	Day	10% 5% 1 4 4 3 3 2 4 6% 57%	1800
	21st to end	Day	14% 5% 2 5% 3 2 2 2 4 5% 55%	1800
December	1st to 10th	Day	6% 6% 3 5% 3 3 3 3 4 6% 59%	2940
	11th to 20th	Day	9% 6% 2 6% 4 4 4 3 4 4 53%	3391
	21st to end	Day	18% 13% 6% 9% 4 4 3 3 4 5% 30%	4488
January	1st to 10th	Night	13% 8% 3 8% 4 4 4 3 4 6% 44%	5888
	11th to 20th	Night	7% 6% 3 7% 6% 5% 4 3 5% 6% 48%	5900
	21st to end	Night	14% 9% 3 6% 4 2 3 2 4 4 50%	6490
February	1st to 10th	Night	11% 8% 3 7% 5% 4 4 4 4 6% 44%	2600
	11th to 20th	Night	12% 9% 2 6% 4 4 3 3 4 5% 48%	2449
	21st to end	Night	11% 6% 2 5% 3 3 3 3 6% 6% 51%	1961
March	1st to 10th	Night	13% 6% 2 4 3 3 2 3 4 5% 54%	3529
	11th to 20th	Night	9% 4 1 4 3 3 3 3 4 6% 59%	3497
	21st to end	Night	14% 8% 3 6% 4 4 3 3 5% 6% 45%	3817
April	1st to 10th	Night	10% 5% 2 5% 4 3 3 3 5% 6% 52%	2062
	11th to 20th	Night	12% 7% 2 6% 4 3 3 3 4 6% 50%	1861
	21st to end	Night	15% 6% 2 6% 3 3 3 3 5% 6% 46%	1710
May	1st to 10th	Night	16% 9% 3 6% 4 3 3 3 5% 7% 41%	2823
	11th to 20th	Night	14% 7% 2 7% 3 3 3 3 5% 7% 46%	2823
	21st to end	Night	10% 5% 2 4 3 3 3 3 5% 8% 53%	3090
June	1st to 10th	Night	5% 3 2 5% 3 4 5% 5% 5% 10% 54%	1710
	11th to 20th	Night	4 4 2 4 3 4 4 5% 8% 11% 52%	1710
	21st to end	Night	5% 3 2 5% 3 3 4 4 6% 9% 57%	1710
July	1st to 10th	Night	7% 5% 2 6% 4 4 4 3 5% 8% 52%	2850
	11th to 20th	Night	2 2 1 5% 4 4 4 4 6% 12% 57%	2850
	21st to end	Night	6% 4 2 6% 4 5% 6% 5% 9% 10% 43%	3098
August	1st to 10th	Night	3 2 1 4 4 3 4 4 7% 9% 58%	2836
	11th to 20th	Night	7% 4 1 5% 4 4 5% 4 6% 7% 52%	2798
	21st to end	Night	3 2 1 4 3 3 4 3 5% 6% 65%	3311
September	1st to 10th	Night	10% 4 2 4 3 2 3 2 4 5% 60%	2006
	11th to 20th	Night	9% 4 2 5% 3 3 5% 4 6% 6% 53%	2090
	21st to end	Night	7% 3 1 4 3 3 4 3 5% 6% 60%	2090
October	1st to 10th	Night	10% 5% 1 5% 3 3 3 3 4 7% 57%	2205
	11th to 20th	Night	12% 4 2 4 3 2 3 2 4 5% 60%	2280
	21st to end	Night	14% 6% 2 4 3 3 3 3 4 5% 55%	2508
November	1st to 10th	Night	10% 5% 1 4 2 3 2 3 4 4 62%	2385
	11th to 20th	Night	10% 6% 2 4 2 3 3 3 4 8% 56%	2600
	21st to end	Night	13% 8% 2 3 3 2 3 3 3 5% 55%	2600
December	1st to 10th	Night	7% 4 1 4 3 2 3 3 4 5% 63%	4250
	11th to 20th	Night	11% 6% 2 5% 3 3 3 3 4 5% 55%	4816
	21st to end	Night	20% 10% 5% 7% 4 4 3 3 4 5% 36%	6490

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	44% 4 11% 24% 15% 2	4078
	11th to 20th	Day	42% 4 10% 22% 19% 3	4080
	21st to end	Day	42% 3 9% 21% 20% 5%	4488
February	1st to 10th	Day	45% 4 11% 25% 11% 3	1800
	11th to 20th	Day	41% 5% 11% 25% 15% 4	1862
	21st to end	Day	39% 5% 9% 22% 18% 7%	1668
March	1st to 10th	Day	37% 3 6% 23% 25% 6%	3546
	11th to 20th	Day	28% 5% 13% 29% 23% 3	3491
	21st to end	Day	44% 8% 12% 26% 9% 1	3814
April	1st to 10th	Day	35% 7% 13% 23% 19% 4	2118
	11th to 20th	Day	42% 5% 11% 23% 17% 3	2264
	21st to end	Day	44% 6% 11% 25% 13% 1	2470
May	1st to 10th	Day	49% 6% 9% 19% 13% 3	4120
	11th to 20th	Day	37% 8% 12% 27% 15%	4086
	21st to end	Day	40% 8% 12% 22% 15% 3	4489
June	1st to 10th	Day	28% 9% 17% 27% 16% 2	2470
	11th to 20th	Day	29% 7% 12% 30% 19% 2	2470
	21st to end	Day	23% 6% 16% 29% 21% 5%	2470
July	1st to 10th	Day	37% 6% 11% 23% 18% 4	4056
	11th to 20th	Day	27% 6% 12% 34% 20% 2	4051
	21st to end	Day	32% 6% 19% 28% 15%	4325
August	1st to 10th	Day	27% 6% 13% 25% 24% 5%	4090
	11th to 20th	Day	35% 5% 17% 25% 17% 1	4080
	21st to end	Day	24% 5% 15% 36% 15% 5%	4348
September	1st to 10th	Day	32% 5% 11% 25% 20% 7%	2169
	11th to 20th	Day	31% 6% 10% 26% 24% 3	2090
	21st to end	Day	30% 5% 9% 23% 29% 5%	2090
October	1st to 10th	Day	21% 4 7% 18% 41% 11%	3240
	11th to 20th	Day	15% 3 5% 31% 33% 12%	3140
	21st to end	Day	28% 3 8% 27% 27% 7%	3428
November	1st to 10th	Day	27% 5% 10% 31% 22% 6%	1909
	11th to 20th	Day	30% 4 9% 27% 25% 5%	1800
	21st to end	Day	33% 2 10% 29% 23% 2	1800
December	1st to 10th	Day	28% 4 9% 37% 21% 1	2940
	11th to 20th	Day	35% 3 7% 32% 20% 2	3389
	21st to end	Day	56% 5% 10% 21% 7% 1	4488
January	1st to 10th	Night	41% 3 11% 28% 14% 2	5888
	11th to 20th	Night	36% 5% 10% 25% 20% 4	5900
	21st to end	Night	39% 3 10% 21% 23% 5%	6490
February	1st to 10th	Night	41% 5% 12% 24% 14% 4	2600
	11th to 20th	Night	40% 3 11% 26% 17% 3	2450
	21st to end	Night	33% 4 9% 24% 22% 8%	1961
March	1st to 10th	Night	33% 4 9% 25% 23% 6%	3529
	11th to 20th	Night	27% 4 11% 25% 30% 3	3497
	21st to end	Night	39% 7% 16% 25% 12% 1	3817
April	1st to 10th	Night	32% 6% 10% 23% 23% 7%	2062
	11th to 20th	Night	35% 4 13% 23% 19% 5%	1861
	21st to end	Night	38% 6% 13% 23% 18% 3	1710
May	1st to 10th	Night	42% 8% 12% 19% 14% 4	2850
	11th to 20th	Night	38% 6% 14% 27% 14% 1	2824
	21st to end	Night	29% 7% 16% 27% 19% 2	3099
June	1st to 10th	Night	25% 8% 19% 30% 17% 2	1710
	11th to 20th	Night	24% 7% 16% 30% 19% 3	1710
	21st to end	Night	22% 6% 15% 32% 20% 5%	1710
July	1st to 10th	Night	31% 5% 13% 25% 22% 4	2805
	11th to 20th	Night	21% 5% 13% 36% 23% 3	2796
	21st to end	Night	31% 5% 21% 28% 13% 1	2999
August	1st to 10th	Night	21% 5% 16% 30% 20% 9%	2826
	11th to 20th	Night	29% 5% 16% 27% 20% 3	2825
	21st to end	Night	19% 4 14% 39% 19% 4	3311
September	1st to 10th	Night	27% 5% 11% 27% 21% 10%	2006
	11th to 20th	Night	29% 6% 11% 23% 25% 5%	2090
	21st to end	Night	24% 5% 10% 25% 30% 6%	2090
October	1st to 10th	Night	18% 3 6% 15% 46% 13%	3686
	11th to 20th	Night	19% 2 5% 24% 34% 15%	3779
	21st to end	Night	27% 4 7% 26% 31% 5%	4120
November	1st to 10th	Night	26% 4 10% 29% 25% 7%	2385
	11th to 20th	Night	29% 4 8% 25% 29% 5%	2600
	21st to end	Night	33% 4 9% 26% 23% 5%	2600
December	1st to 10th	Night	24% 4 12% 40% 19% 1	4250
	11th to 20th	Night	33% 3 9% 30% 22% 4	4817
	21st to end	Night	50% 4 9% 25% 10% 2	6490

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	20% 13% 35% 25% 7%	300
	11th to 20th	Day	22% 17% 39% 19% 4	300
	21st to end	Day	11% 14% 50% 22% 2 1	330
February	1st to 10th	Day	25% 17% 34% 20% 4 1	300
	11th to 20th	Day	15% 18% 43% 19% 4	300
	21st to end	Day	16% 22% 41% 16% 4	249
March	1st to 10th	Day	18% 19% 37% 23% 3	300
	11th to 20th	Day	22% 16% 34% 22% 5% 1	273
	21st to end	Day	23% 23% 35% 16% 2 1	297
April	1st to 10th	Day	17% 20% 39% 20% 4	298
	11th to 20th	Day	20% 17% 37% 21% 5%	462
	21st to end	Day	22% 14% 36% 18% 8% 1	650
May	1st to 10th	Day	19% 12% 37% 22% 9% 1	653
	11th to 20th	Day	18% 12% 29% 27% 13% 2	675
	21st to end	Day	18% 8% 31% 23% 16% 4	734
June	1st to 10th	Day	6% 5% 22% 35% 26% 6%	680
	11th to 20th	Day	9% 3 30% 38% 17% 4	680
	21st to end	Day	6% 4 30% 39% 18% 2	680
July	1st to 10th	Day	10% 4 15% 32% 29% 10%	671
	11th to 20th	Day	5% 2 14% 38% 34% 7%	668
	21st to end	Day	7% 2 12% 37% 31% 10%	739
August	1st to 10th	Day	7% 3 16% 37% 30% 6%	676
	11th to 20th	Day	8% 2 18% 36% 30% 7%	665
	21st to end	Day	8% 1 14% 32% 36% 10%	643
September	1st to 10th	Day	13% 2 11% 35% 32% 7%	379
	11th to 20th	Day	6% 2 18% 38% 28% 8%	300
	21st to end	Day	15% 4 23% 36% 16% 6%	300
October	1st to 10th	Day	14% 5% 27% 28% 18% 9%	300
	11th to 20th	Day	8% 10% 47% 26% 9%	300
	21st to end	Day	24% 10% 33% 22% 9% 2	330
November	1st to 10th	Day	16% 12% 33% 25% 12% 3	300
	11th to 20th	Day	17% 17% 34% 18% 11% 2	300
	21st to end	Day	19% 13% 38% 21% 10%	300
December	1st to 10th	Day	11% 12% 41% 25% 8% 2	300
	11th to 20th	Day	16% 14% 36% 24% 9% 1	300
	21st to end	Day	17% 24% 35% 19% 5%	330
January	1st to 10th	Night	13% 13% 39% 29% 6%	1000
	11th to 20th	Night	15% 13% 38% 28% 6%	1000
	21st to end	Night	13% 12% 39% 31% 5%	1100
February	1st to 10th	Night	16% 14% 40% 26% 4	1000
	11th to 20th	Night	17% 14% 38% 27% 2	895
	21st to end	Night	15% 14% 39% 28% 5%	641
March	1st to 10th	Night	15% 11% 41% 29% 5%	600
	11th to 20th	Night	18% 12% 37% 28% 6%	575
	21st to end	Night	20% 15% 39% 23% 4	627
April	1st to 10th	Night	14% 14% 41% 26% 6%	570
	11th to 20th	Night	16% 15% 39% 26% 5%	563
	21st to end	Night	17% 13% 36% 26% 7% 1	570
May	1st to 10th	Night	18% 8% 36% 30% 6% 1	570
	11th to 20th	Night	15% 7% 31% 32% 15%	561
	21st to end	Night	12% 6% 30% 32% 17% 2	617
June	1st to 10th	Night	6% 3 22% 44% 24% 1	570
	11th to 20th	Night	5% 4 29% 44% 18%	570
	21st to end	Night	5% 3 34% 44% 14% 1	570
July	1st to 10th	Night	7% 2 16% 44% 30% 2	555
	11th to 20th	Night	2 1 16% 50% 28% 2	552
	21st to end	Night	6% 2 15% 44% 31% 3	624
August	1st to 10th	Night	4 2 17% 46% 29% 1	567
	11th to 20th	Night	7% 2 16% 48% 27% 1	564
	21st to end	Night	5% 1 14% 40% 38% 3	627
September	1st to 10th	Night	12% 1 18% 44% 23% 2	570
	11th to 20th	Night	10% 2 24% 38% 23% 4	570
	21st to end	Night	9% 5% 23% 42% 18% 3	570
October	1st to 10th	Night	12% 4 26% 35% 21% 2	685
	11th to 20th	Night	14% 8% 38% 33% 7%	760
	21st to end	Night	16% 13% 32% 28% 10%	836
November	1st to 10th	Night	13% 9% 37% 29% 11% 1	825
	11th to 20th	Night	13% 13% 36% 31% 8%	1000
	21st to end	Night	18% 12% 30% 32% 8%	1000
December	1st to 10th	Night	15% 10% 37% 32% 7%	1000
	11th to 20th	Night	17% 11% 36% 32% 5%	1000
	21st to end	Night	18% 14% 35% 29% 5%	1100

Page generated at 2025-03-09 07:08:44. Version ac07

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