Hwy 29 and Benndale Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hwy 29 and Benndale Road clear sky chart from 2005-11-06 to 2024-11-10.

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	12% 6% 2 7% 5% 5% 5% 4 6% 8% 41%	100759
	Night	12% 6% 2 6% 4 4 4 4 6% 8% 44%	98297
Transparency	Day	39% 7% 11% 18% 18% 8%	104582
	Night	36% 7% 12% 18% 19% 9%	102614
Seeing	Day	14% 9% 20% 25% 21% 10%	14476
	Night	14% 7% 21% 30% 22% 6%	24172

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	17% 7% 2 4 3 3 4 3 6% 8% 43%	3156
	11th to 20th	Day	12% 5% 2 5% 3 3 4 3 4 5% 55%	3160
	21st to end	Day	24% 8% 2 6% 3 3 3 3 4 5% 40%	3476
February	1st to 10th	Day	18% 8% 3 7% 5% 4 4 4 4 5% 38%	1900
	11th to 20th	Day	20% 5% 2 4 4 4 4 3 4 7% 43%	1848
	21st to end	Day	16% 9% 2 7% 5% 3 4 5% 4 6% 39%	1570
March	1st to 10th	Day	21% 11% 3 8% 4 4 4 4 5% 5% 32%	3120
	11th to 20th	Day	16% 6% 2 7% 5% 4 4 3 6% 9% 38%	3405
	21st to end	Day	13% 6% 3 7% 5% 5% 5% 4 5% 5% 41%	4126
April	1st to 10th	Day	12% 6% 3 6% 5% 4 5% 4 6% 7% 42%	2280
	11th to 20th	Day	14% 6% 3 6% 5% 4 5% 4 6% 7% 41%	2254
	21st to end	Day	9% 5% 2 6% 5% 5% 4 4 5% 7% 50%	2280
May	1st to 10th	Day	10% 5% 2 6% 6% 5% 6% 5% 7% 10% 38%	3765
	11th to 20th	Day	14% 6% 3 7% 5% 4 5% 3 5% 7% 41%	3764
	21st to end	Day	6% 5% 2 6% 5% 5% 5% 4 7% 11% 43%	4467
June	1st to 10th	Day	10% 7% 3 7% 7% 5% 6% 6% 8% 10% 31%	2470
	11th to 20th	Day	5% 5% 2 8% 7% 7% 6% 6% 9% 9% 37%	2470
	21st to end	Day	7% 8% 2 8% 8% 8% 8% 6% 8% 9% 29%	2570
July	1st to 10th	Day	8% 6% 3 10% 7% 8% 9% 6% 9% 11% 24%	4076
	11th to 20th	Day	7% 6% 2 8% 7% 7% 7% 6% 8% 11% 30%	3800
	21st to end	Day	8% 6% 2 9% 7% 9% 8% 7% 9% 12% 22%	4118
August	1st to 10th	Day	4 3 2 5% 5% 5% 5% 4 7% 8% 52%	3785
	11th to 20th	Day	7% 4 2 6% 5% 6% 6% 5% 7% 10% 41%	3729
	21st to end	Day	8% 5% 3 9% 6% 6% 6% 5% 7% 9% 35%	4180
September	1st to 10th	Day	10% 7% 3 9% 6% 6% 6% 4 7% 8% 34%	2280
	11th to 20th	Day	12% 6% 2 7% 5% 4 5% 4 5% 7% 43%	2154
	21st to end	Day	10% 5% 2 5% 4 4 4 3 5% 6% 51%	2090
October	1st to 10th	Day	7% 4 2 5% 4 4 3 3 5% 6% 56%	2090
	11th to 20th	Day	8% 5% 2 5% 3 4 3 3 4 7% 55%	1947
	21st to end	Day	10% 5% 2 5% 3 3 4 3 4 6% 56%	2090
November	1st to 10th	Day	10% 6% 2 6% 3 3 2 3 4 6% 55%	1869
	11th to 20th	Day	12% 5% 2 4 4 3 3 3 4 6% 55%	1710
	21st to end	Day	13% 6% 3 6% 4 3 4 4 4 6% 47%	1710
December	1st to 10th	Day	15% 8% 3 5% 5% 3 5% 3 5% 7% 44%	1710
	11th to 20th	Day	16% 8% 3 7% 4 4 4 2 4 4 42%	2153
	21st to end	Day	17% 7% 2 6% 4 5% 4 4 5% 6% 40%	3187
January	1st to 10th	Night	18% 7% 2 5% 3 3 3 3 5% 5% 48%	3789
	11th to 20th	Night	15% 8% 2 4 2 3 3 2 4 5% 52%	3800
	21st to end	Night	26% 9% 2 4 3 2 2 2 4 5% 42%	4180
February	1st to 10th	Night	16% 8% 3 5% 4 5% 4 3 4 6% 42%	2280
	11th to 20th	Night	21% 8% 2 5% 3 3 3 3 4 5% 42%	2218
	21st to end	Night	18% 9% 2 7% 4 4 4 3 4 5% 39%	1884
March	1st to 10th	Night	23% 12% 3 7% 4 4 4 3 4 5% 32%	3733
	11th to 20th	Night	15% 7% 3 5% 5% 4 5% 4 6% 7% 39%	3582
	21st to end	Night	14% 7% 2 5% 4 3 4 4 5% 6% 45%	3503
April	1st to 10th	Night	14% 7% 2 6% 4 4 4 3 5% 6% 45%	1900
	11th to 20th	Night	14% 7% 2 6% 3 3 3 4 6% 6% 46%	1875
	21st to end	Night	8% 4 1 5% 4 3 3 2 4 7% 59%	1900
May	1st to 10th	Night	13% 6% 2 7% 4 3 4 3 4 9% 44%	3130
	11th to 20th	Night	14% 6% 2 7% 5% 4 4 3 6% 7% 43%	3129
	21st to end	Night	6% 4 2 6% 5% 5% 5% 5% 8% 12% 43%	3083
June	1st to 10th	Night	7% 6% 2 6% 6% 6% 4 5% 8% 11% 38%	1710
	11th to 20th	Night	3 4 2 4 5% 5% 6% 6% 9% 11% 44%	1710
	21st to end	Night	7% 6% 2 6% 5% 5% 5% 6% 8% 10% 41%	1589
July	1st to 10th	Night	5% 6% 2 7% 6% 6% 6% 5% 9% 12% 36%	2841
	11th to 20th	Night	5% 4 2 7% 5% 6% 6% 6% 9% 13% 37%	3160
	21st to end	Night	6% 5% 3 9% 7% 6% 7% 6% 10% 13% 29%	3435
August	1st to 10th	Night	2 2 1 4 3 4 5% 5% 8% 13% 53%	3144
	11th to 20th	Night	4 3 2 5% 4 5% 6% 5% 8% 14% 44%	3100
	21st to end	Night	5% 4 3 7% 5% 6% 7% 5% 8% 10% 40%	3476
September	1st to 10th	Night	10% 7% 3 8% 5% 6% 5% 5% 6% 9% 36%	1900
	11th to 20th	Night	9% 6% 3 6% 4 4 4 4 7% 8% 44%	2004
	21st to end	Night	8% 5% 2 6% 3 4 4 4 6% 7% 51%	2090
October	1st to 10th	Night	7% 4 2 5% 3 4 4 4 5% 7% 54%	2090
	11th to 20th	Night	8% 4 1 3 3 3 4 3 5% 7% 59%	2228
	21st to end	Night	12% 5% 2 5% 3 3 3 2 4 5% 57%	2508
November	1st to 10th	Night	10% 4 1 6% 3 3 4 3 4 5% 57%	2410
	11th to 20th	Night	12% 5% 1 4 2 3 3 3 5% 6% 56%	2470
	21st to end	Night	13% 7% 2 5% 3 3 4 3 5% 6% 48%	2470
December	1st to 10th	Night	14% 7% 2 6% 4 3 3 3 6% 6% 46%	2470
	11th to 20th	Night	16% 8% 3 5% 4 4 4 4 4 5% 44%	3042
	21st to end	Night	17% 8% 3 6% 4 4 4 3 4 5% 42%	4464

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	39% 4 6% 18% 24% 11%	3157
	11th to 20th	Day	31% 4 5% 20% 30% 10%	3160
	21st to end	Day	48% 3 4 14% 22% 9%	3476
February	1st to 10th	Day	48% 4 7% 12% 19% 10%	1900
	11th to 20th	Day	41% 5% 6% 15% 22% 10%	1858
	21st to end	Day	46% 4 7% 16% 17% 10%	1570
March	1st to 10th	Day	53% 5% 8% 16% 13% 5%	3120
	11th to 20th	Day	44% 5% 8% 19% 19% 5%	3405
	21st to end	Day	43% 5% 9% 15% 19% 9%	4126
April	1st to 10th	Day	39% 7% 8% 17% 19% 10%	2280
	11th to 20th	Day	42% 5% 6% 17% 21% 8%	2254
	21st to end	Day	33% 6% 9% 21% 23% 8%	2280
May	1st to 10th	Day	37% 8% 13% 23% 15% 4	3800
	11th to 20th	Day	42% 6% 11% 18% 20% 3	3768
	21st to end	Day	32% 8% 14% 31% 12% 2	4480
June	1st to 10th	Day	44% 9% 14% 21% 9% 2	2470
	11th to 20th	Day	39% 8% 15% 23% 11% 3	2470
	21st to end	Day	46% 11% 17% 16% 8% 1	2570
July	1st to 10th	Day	48% 13% 21% 14% 3	4016
	11th to 20th	Day	44% 12% 31% 11% 2 1	3737
	21st to end	Day	50% 14% 18% 14% 4 1	3987
August	1st to 10th	Day	27% 8% 14% 26% 24% 2	3773
	11th to 20th	Day	36% 9% 16% 23% 15% 1	3765
	21st to end	Day	43% 11% 15% 15% 15% 2	4179
September	1st to 10th	Day	45% 9% 12% 17% 12% 5%	2280
	11th to 20th	Day	40% 8% 11% 16% 17% 7%	2154
	21st to end	Day	33% 5% 11% 22% 20% 10%	2090
October	1st to 10th	Day	27% 3 7% 11% 22% 30%	3480
	11th to 20th	Day	18% 3 5% 16% 27% 31%	3213
	21st to end	Day	22% 4 4 13% 37% 21%	3428
November	1st to 10th	Day	32% 3 7% 19% 25% 13%	1869
	11th to 20th	Day	32% 3 6% 17% 29% 13%	1710
	21st to end	Day	38% 4 7% 18% 20% 13%	1710
December	1st to 10th	Day	41% 4 9% 18% 20% 8%	1710
	11th to 20th	Day	46% 4 7% 12% 22% 9%	2150
	21st to end	Day	44% 5% 7% 20% 19% 6%	3187
January	1st to 10th	Night	39% 4 6% 14% 29% 8%	3789
	11th to 20th	Night	36% 4 5% 18% 27% 11%	3800
	21st to end	Night	47% 3 4 15% 24% 7%	4180
February	1st to 10th	Night	43% 4 8% 16% 20% 10%	2280
	11th to 20th	Night	45% 4 4 13% 21% 12%	2219
	21st to end	Night	48% 4 8% 14% 13% 13%	1884
March	1st to 10th	Night	55% 4 8% 13% 13% 6%	3733
	11th to 20th	Night	43% 6% 9% 16% 19% 7%	3582
	21st to end	Night	40% 5% 10% 20% 18% 8%	3503
April	1st to 10th	Night	40% 5% 9% 15% 20% 11%	1900
	11th to 20th	Night	37% 5% 9% 20% 19% 9%	1875
	21st to end	Night	27% 4 11% 23% 26% 8%	1900
May	1st to 10th	Night	38% 7% 13% 20% 17% 4	3160
	11th to 20th	Night	39% 7% 12% 24% 17% 1	3130
	21st to end	Night	29% 9% 19% 27% 13% 2	3091
June	1st to 10th	Night	35% 10% 20% 23% 11% 2	1710
	11th to 20th	Night	29% 11% 21% 26% 12% 2	1710
	21st to end	Night	34% 10% 22% 23% 8% 2	1589
July	1st to 10th	Night	37% 14% 30% 15% 4	2793
	11th to 20th	Night	33% 16% 37% 11% 2 1	3100
	21st to end	Night	43% 17% 19% 18% 3	3325
August	1st to 10th	Night	19% 8% 23% 29% 20% 1	3132
	11th to 20th	Night	28% 12% 22% 25% 13% 1	3130
	21st to end	Night	36% 14% 17% 19% 11% 4	3476
September	1st to 10th	Night	41% 10% 16% 14% 14% 6%	1900
	11th to 20th	Night	36% 8% 18% 16% 15% 8%	2004
	21st to end	Night	31% 7% 11% 23% 17% 10%	2090
October	1st to 10th	Night	30% 4 7% 10% 24% 24%	3480
	11th to 20th	Night	16% 3 5% 20% 23% 33%	3701
	21st to end	Night	20% 3 4 12% 37% 24%	4120
November	1st to 10th	Night	31% 3 8% 18% 25% 16%	2410
	11th to 20th	Night	30% 3 6% 17% 28% 15%	2470
	21st to end	Night	36% 4 7% 20% 19% 14%	2470
December	1st to 10th	Night	38% 5% 9% 21% 21% 7%	2470
	11th to 20th	Night	43% 4 6% 13% 23% 11%	3044
	21st to end	Night	44% 4 6% 19% 21% 5%	4464

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	25% 16% 38% 15% 5% 1	270
	11th to 20th	Day	24% 16% 31% 20% 8% 1	270
	21st to end	Day	29% 24% 31% 13% 4	297
February	1st to 10th	Day	29% 22% 28% 14% 6%	270
	11th to 20th	Day	31% 19% 29% 15% 6%	270
	21st to end	Day	21% 29% 38% 9% 3	225
March	1st to 10th	Day	20% 21% 36% 18% 5%	270
	11th to 20th	Day	23% 26% 29% 18% 4	270
	21st to end	Day	19% 18% 29% 25% 9%	480
April	1st to 10th	Day	20% 15% 32% 22% 10% 2	460
	11th to 20th	Day	21% 16% 29% 22% 10% 2	452
	21st to end	Day	12% 11% 30% 27% 17% 2	460
May	1st to 10th	Day	10% 12% 29% 23% 19% 6%	463
	11th to 20th	Day	10% 6% 24% 30% 22% 9%	487
	21st to end	Day	8% 2 22% 31% 25% 12%	529
June	1st to 10th	Day	12% 4 16% 29% 26% 14%	490
	11th to 20th	Day	7% 2 13% 32% 30% 16%	490
	21st to end	Day	9% 3 12% 29% 29% 17%	590
July	1st to 10th	Day	7% 3 7% 30% 32% 20%	602
	11th to 20th	Day	6% 3 6% 16% 41% 29%	484
	21st to end	Day	8% 1 8% 22% 39% 23%	532
August	1st to 10th	Day	5% 2 7% 24% 34% 28%	486
	11th to 20th	Day	8% 2 6% 18% 36% 29%	479
	21st to end	Day	11% 3 9% 22% 34% 22%	539
September	1st to 10th	Day	10% 3 8% 27% 33% 19%	490
	11th to 20th	Day	14% 5% 8% 26% 34% 12%	490
	21st to end	Day	12% 4 13% 30% 31% 11%	490
October	1st to 10th	Day	8% 6% 22% 36% 22% 7%	490
	11th to 20th	Day	10% 7% 22% 32% 23% 7%	347
	21st to end	Day	18% 11% 17% 31% 18% 5%	330
November	1st to 10th	Day	17% 8% 27% 33% 13% 2	297
	11th to 20th	Day	19% 13% 29% 26% 13% 1	270
	21st to end	Day	14% 19% 31% 24% 10% 3	270
December	1st to 10th	Day	18% 18% 31% 23% 8% 1	270
	11th to 20th	Day	26% 15% 37% 17% 5%	270
	21st to end	Day	30% 13% 27% 22% 7%	297
January	1st to 10th	Night	22% 13% 34% 26% 5%	760
	11th to 20th	Night	20% 13% 29% 30% 7%	760
	21st to end	Night	24% 13% 32% 27% 4	836
February	1st to 10th	Night	20% 13% 32% 30% 5%	760
	11th to 20th	Night	26% 15% 29% 24% 6%	743
	21st to end	Night	22% 19% 36% 20% 3	628
March	1st to 10th	Night	18% 15% 33% 28% 7%	760
	11th to 20th	Night	16% 10% 35% 31% 6% 1	633
	21st to end	Night	14% 12% 33% 32% 9%	627
April	1st to 10th	Night	16% 12% 30% 30% 12% 1	570
	11th to 20th	Night	15% 10% 33% 27% 14% 1	563
	21st to end	Night	10% 6% 27% 38% 17%	570
May	1st to 10th	Night	10% 5% 26% 39% 18% 2	570
	11th to 20th	Night	9% 4 18% 41% 24% 4	561
	21st to end	Night	6% 2 18% 37% 31% 7%	617
June	1st to 10th	Night	10% 2 13% 32% 35% 7%	570
	11th to 20th	Night	4 2 8% 35% 41% 11%	570
	21st to end	Night	8% 2 8% 27% 41% 13%	570
July	1st to 10th	Night	5% 1 5% 21% 50% 17%	555
	11th to 20th	Night	4 1 4 16% 48% 27%	552
	21st to end	Night	5% 1 4 22% 49% 20%	624
August	1st to 10th	Night	4 1 2 20% 47% 26%	567
	11th to 20th	Night	8% 1 3 18% 47% 23%	564
	21st to end	Night	8% 2 6% 19% 45% 20%	627
September	1st to 10th	Night	12% 3 6% 24% 41% 14%	570
	11th to 20th	Night	11% 3 7% 30% 41% 8%	674
	21st to end	Night	10% 3 11% 33% 37% 7%	760
October	1st to 10th	Night	9% 2 20% 36% 30% 4	760
	11th to 20th	Night	10% 5% 22% 35% 25% 4	760
	21st to end	Night	13% 6% 22% 34% 23% 2	836
November	1st to 10th	Night	12% 7% 20% 40% 19% 2	779
	11th to 20th	Night	15% 9% 26% 36% 13% 1	760
	21st to end	Night	16% 9% 26% 33% 14% 2	760
December	1st to 10th	Night	18% 13% 26% 30% 13% 1	760
	11th to 20th	Night	21% 9% 30% 30% 8% 1	760
	21st to end	Night	24% 11% 30% 28% 8%	836

Page generated at 2024-11-07 05:55:45. Version ac07

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