Toronto(KS)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Toronto(KS) clear sky chart from 2005-11-05 to 2024-10-14.

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	11% 6% 2 6% 4 4 4 3 5% 7% 47%	101070
	Night	10% 6% 2 5% 4 3 4 3 5% 7% 51%	97588
Transparency	Day	36% 6% 12% 26% 18% 3	100883
	Night	33% 5% 12% 26% 20% 4	97451
Seeing	Day	14% 9% 28% 28% 17% 4	15515
	Night	13% 9% 32% 33% 12% 1	25321

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	12% 9% 3 9% 5% 5% 4 3 4 6% 40%	2847
	11th to 20th	Day	10% 10% 3 7% 6% 7% 4 3 4 6% 38%	2850
	21st to end	Day	14% 14% 5% 7% 4 3 3 2 3 5% 40%	3135
February	1st to 10th	Day	14% 8% 4 7% 4 4 3 2 5% 6% 43%	1710
	11th to 20th	Day	10% 8% 3 8% 3 4 4 3 4 6% 46%	1758
	21st to end	Day	11% 8% 2 7% 5% 4 4 4 6% 6% 44%	1587
March	1st to 10th	Day	13% 8% 3 5% 3 3 2 2 3 6% 52%	3436
	11th to 20th	Day	11% 5% 1 4 2 3 3 3 5% 7% 56%	3480
	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% 5% 1 3 2 3 3 3 5% 6% 59%	1830
	21st to end	Day	16% 6% 2 4 3 3 3 2 4 5% 51%	1980
November	1st to 10th	Day	9% 6% 2 4 2 2 3 2 4 6% 60%	1812
	11th to 20th	Day	10% 5% 2 4 4 3 3 2 4 6% 57%	1710
	21st to end	Day	15% 5% 2 5% 3 2 2 2 4 5% 55%	1710
December	1st to 10th	Day	10% 7% 3 6% 3 3 4 4 4 7% 49%	1710
	11th to 20th	Day	13% 8% 3 7% 5% 4 4 3 4 4 44%	2161
	21st to end	Day	15% 11% 7% 9% 5% 4 3 4 5% 7% 30%	3135
January	1st to 10th	Night	10% 8% 3 9% 4 4 4 3 4 5% 46%	4108
	11th to 20th	Night	8% 7% 3 7% 6% 6% 5% 4 4 5% 45%	4120
	21st to end	Night	18% 11% 3 5% 3 2 3 2 4 4 44%	4532
February	1st to 10th	Night	11% 8% 3 7% 5% 5% 4 4 4 6% 44%	2470
	11th to 20th	Night	12% 8% 2 6% 4 3 3 3 4 5% 49%	2324
	21st to end	Night	12% 7% 3 5% 3 3 3 3 6% 6% 50%	1866
March	1st to 10th	Night	13% 6% 2 4 3 3 2 3 4 5% 54%	3419
	11th to 20th	Night	9% 4 1 4 3 3 4 3 4 6% 59%	3480
	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% 59%	2203
	21st to end	Night	14% 6% 2 4 3 2 3 3 4 5% 54%	2376
November	1st to 10th	Night	9% 5% 1 4 2 3 2 3 4 4 62%	2262
	11th to 20th	Night	10% 6% 1 4 2 3 4 3 4 8% 56%	2470
	21st to end	Night	14% 8% 2 4 3 2 3 3 3 5% 54%	2470
December	1st to 10th	Night	11% 7% 1 5% 3 3 3 3 5% 6% 51%	2470
	11th to 20th	Night	11% 7% 2 6% 4 4 3 4 4 5% 50%	3036
	21st to end	Night	18% 10% 6% 7% 4 5% 3 3 4 5% 36%	4532

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% 5% 11% 24% 15% 1	2848
	11th to 20th	Day	47% 5% 14% 22% 10% 3	2850
	21st to end	Day	49% 3 11% 20% 17% 1	3135
February	1st to 10th	Day	45% 5% 12% 25% 11% 3	1710
	11th to 20th	Day	40% 5% 11% 25% 15% 4	1767
	21st to end	Day	40% 5% 9% 22% 17% 7%	1587
March	1st to 10th	Day	36% 3 6% 24% 26% 5%	3436
	11th to 20th	Day	28% 5% 13% 29% 23% 3	3480
	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	31% 6% 11% 24% 25% 4	1954
	11th to 20th	Day	26% 5% 9% 26% 28% 6%	1830
	21st to end	Day	36% 5% 11% 23% 20% 7%	1980
November	1st to 10th	Day	26% 5% 10% 31% 23% 6%	1812
	11th to 20th	Day	29% 4 10% 27% 26% 4	1710
	21st to end	Day	34% 3 10% 28% 24% 3	1710
December	1st to 10th	Day	35% 6% 9% 31% 17% 1	1710
	11th to 20th	Day	42% 5% 8% 26% 16% 3	2159
	21st to end	Day	53% 6% 11% 19% 9% 2	3135
January	1st to 10th	Night	40% 4 10% 29% 14% 3	4108
	11th to 20th	Night	39% 6% 12% 25% 16% 2	4120
	21st to end	Night	43% 4 13% 22% 17% 2	4532
February	1st to 10th	Night	41% 5% 12% 24% 15% 3	2470
	11th to 20th	Night	38% 4 11% 26% 17% 3	2325
	21st to end	Night	34% 4 9% 24% 20% 9%	1866
March	1st to 10th	Night	33% 4 9% 25% 23% 6%	3419
	11th to 20th	Night	27% 4 11% 26% 30% 3	3480
	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	28% 4 10% 20% 28% 9%	2205
	11th to 20th	Night	28% 3 8% 28% 26% 8%	2208
	21st to end	Night	32% 5% 8% 22% 27% 6%	2376
November	1st to 10th	Night	25% 4 10% 29% 25% 7%	2262
	11th to 20th	Night	29% 4 8% 25% 29% 4	2470
	21st to end	Night	34% 4 9% 24% 24% 5%	2470
December	1st to 10th	Night	32% 5% 13% 28% 19% 2	2470
	11th to 20th	Night	35% 4 8% 29% 20% 3	3037
	21st to end	Night	49% 5% 10% 23% 11% 3	4532

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% 23% 8%	270
	11th to 20th	Day	24% 16% 38% 19% 3	270
	21st to end	Day	11% 13% 49% 23% 2 1	297
February	1st to 10th	Day	23% 17% 35% 21% 3 1	270
	11th to 20th	Day	14% 18% 43% 20% 5%	270
	21st to end	Day	17% 24% 40% 15% 4	225
March	1st to 10th	Day	18% 20% 37% 23% 3	270
	11th to 20th	Day	22% 16% 35% 21% 5% 1	270
	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	9% 10% 49% 25% 7%	279
	21st to end	Day	26% 10% 32% 22% 9% 1	297
November	1st to 10th	Day	14% 12% 34% 24% 13% 3	270
	11th to 20th	Day	17% 16% 36% 19% 10% 2	270
	21st to end	Day	21% 11% 37% 21% 9%	270
December	1st to 10th	Day	12% 14% 38% 25% 9% 3	270
	11th to 20th	Day	17% 14% 33% 25% 10% 1	270
	21st to end	Day	17% 24% 37% 19% 3	297
January	1st to 10th	Night	12% 13% 38% 30% 7%	950
	11th to 20th	Night	15% 13% 38% 28% 6%	950
	21st to end	Night	14% 12% 38% 31% 5%	1045
February	1st to 10th	Night	15% 14% 40% 27% 4	950
	11th to 20th	Night	17% 13% 39% 28% 2	850
	21st to end	Night	15% 15% 39% 26% 5%	610
March	1st to 10th	Night	14% 11% 41% 29% 5%	570
	11th to 20th	Night	18% 12% 36% 28% 6%	570
	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% 39% 32% 7%	735
	21st to end	Night	17% 12% 33% 28% 10%	792
November	1st to 10th	Night	11% 9% 38% 30% 11% 1	782
	11th to 20th	Night	12% 12% 36% 32% 8%	950
	21st to end	Night	18% 12% 29% 32% 8%	950
December	1st to 10th	Night	15% 10% 36% 31% 7%	950
	11th to 20th	Night	17% 11% 35% 32% 5%	950
	21st to end	Night	17% 14% 35% 28% 5%	1045

Page generated at 2024-10-11 09:50:02. Version ac07

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