Kilpatrick Point Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kilpatrick Point Observatory clear sky chart from 2005-11-06 to 2024-11-03.

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	14% 8% 3 7% 5% 5% 5% 4 6% 7% 37%	101006
	Night	14% 9% 3 6% 4 4 4 4 5% 7% 39%	97933
Transparency	Day	24% 50% 6% 10% 8% 2	100819
	Night	23% 51% 7% 10% 8% 2	97790
Seeing	Day	21% 12% 22% 21% 16% 8%	14913
	Night	20% 10% 18% 28% 20% 4	24928

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% 11% 4 7% 3 3 3 4 5% 5% 37%	2836
	11th to 20th	Day	16% 8% 4 11% 4 4 3 3 4 4 39%	2840
	21st to end	Day	23% 12% 3 5% 3 3 3 2 4 5% 39%	3124
February	1st to 10th	Day	19% 10% 3 7% 4 4 3 4 4 5% 36%	1897
	11th to 20th	Day	22% 10% 2 6% 5% 3 4 3 4 5% 36%	1848
	21st to end	Day	24% 9% 2 6% 4 4 2 3 4 5% 35%	1570
March	1st to 10th	Day	24% 9% 3 5% 3 2 3 3 5% 6% 37%	3263
	11th to 20th	Day	15% 7% 2 5% 4 3 3 3 4 6% 49%	3480
	21st to end	Day	17% 9% 3 7% 5% 4 4 3 4 5% 39%	3815
April	1st to 10th	Day	13% 7% 3 6% 5% 5% 5% 4 6% 7% 40%	2111
	11th to 20th	Day	14% 7% 3 7% 5% 4 4 4 5% 6% 41%	2271
	21st to end	Day	14% 6% 2 6% 6% 4 4 4 5% 7% 41%	2470
May	1st to 10th	Day	18% 8% 3 7% 4 5% 5% 4 5% 8% 33%	4082
	11th to 20th	Day	19% 9% 3 9% 6% 4 5% 4 6% 6% 28%	4081
	21st to end	Day	11% 7% 3 6% 5% 5% 6% 5% 7% 10% 35%	4476
June	1st to 10th	Day	12% 7% 3 9% 6% 7% 6% 4 8% 9% 29%	2470
	11th to 20th	Day	7% 6% 2 7% 7% 7% 7% 6% 8% 9% 34%	2470
	21st to end	Day	9% 6% 2 8% 7% 7% 6% 6% 8% 9% 33%	2470
July	1st to 10th	Day	7% 6% 3 8% 7% 7% 7% 6% 9% 12% 29%	4120
	11th to 20th	Day	11% 7% 3 7% 6% 7% 6% 6% 7% 9% 31%	4120
	21st to end	Day	15% 11% 4 12% 8% 8% 8% 6% 7% 7% 15%	4466
August	1st to 10th	Day	8% 7% 2 8% 6% 6% 7% 5% 8% 10% 32%	4104
	11th to 20th	Day	9% 5% 2 7% 5% 4 7% 5% 8% 13% 34%	3951
	21st to end	Day	8% 5% 2 7% 6% 5% 6% 5% 7% 8% 41%	4156
September	1st to 10th	Day	12% 6% 3 9% 6% 6% 5% 5% 7% 7% 33%	2090
	11th to 20th	Day	14% 7% 3 8% 7% 5% 5% 4 6% 8% 34%	2090
	21st to end	Day	14% 6% 3 7% 4 5% 5% 4 6% 6% 41%	2090
October	1st to 10th	Day	10% 6% 2 5% 4 4 4 3 5% 6% 51%	2090
	11th to 20th	Day	13% 6% 2 5% 3 3 4 3 4 5% 53%	1939
	21st to end	Day	13% 5% 2 5% 4 3 3 3 4 6% 52%	2090
November	1st to 10th	Day	13% 6% 1 4 3 3 4 2 4 6% 55%	1719
	11th to 20th	Day	13% 6% 2 4 3 3 4 4 5% 7% 49%	1710
	21st to end	Day	16% 9% 3 5% 4 4 3 2 5% 5% 44%	1710
December	1st to 10th	Day	24% 8% 3 6% 4 4 4 3 5% 5% 35%	1710
	11th to 20th	Day	17% 9% 3 6% 4 4 4 3 5% 5% 42%	2153
	21st to end	Day	17% 9% 6% 8% 4 3 4 3 5% 7% 34%	3124
January	1st to 10th	Night	16% 13% 5% 6% 4 3 3 2 3 5% 40%	4109
	11th to 20th	Night	19% 11% 3 6% 3 3 3 3 4 5% 40%	4120
	21st to end	Night	23% 16% 3 6% 3 3 3 2 3 3 36%	4532
February	1st to 10th	Night	16% 9% 3 7% 4 4 3 4 5% 6% 39%	2280
	11th to 20th	Night	21% 11% 3 7% 4 4 4 3 4 4 37%	2218
	21st to end	Night	24% 11% 4 6% 4 4 4 3 4 4 33%	1884
March	1st to 10th	Night	21% 13% 4 7% 5% 5% 5% 2 4 5% 30%	3588
	11th to 20th	Night	13% 8% 2 5% 3 4 4 3 6% 8% 45%	3480
	21st to end	Night	15% 9% 3 7% 5% 4 4 3 5% 5% 39%	3817
April	1st to 10th	Night	14% 7% 2 5% 4 3 4 3 6% 8% 43%	2084
	11th to 20th	Night	13% 8% 2 6% 4 3 3 2 6% 8% 45%	1856
	21st to end	Night	12% 6% 2 6% 4 4 4 4 6% 7% 45%	1710
May	1st to 10th	Night	16% 9% 3 8% 5% 4 4 4 5% 8% 35%	2813
	11th to 20th	Night	18% 11% 3 7% 5% 3 4 4 5% 7% 33%	2812
	21st to end	Night	8% 6% 3 6% 5% 5% 6% 5% 7% 11% 40%	3079
June	1st to 10th	Night	10% 8% 2 7% 6% 5% 5% 5% 8% 10% 34%	1710
	11th to 20th	Night	6% 6% 2 5% 5% 5% 5% 4 7% 10% 45%	1710
	21st to end	Night	9% 6% 2 6% 5% 4 6% 6% 6% 10% 40%	1710
July	1st to 10th	Night	9% 7% 3 8% 6% 5% 7% 5% 7% 11% 31%	2840
	11th to 20th	Night	8% 6% 3 7% 5% 5% 6% 5% 9% 11% 35%	2840
	21st to end	Night	15% 11% 4 9% 6% 6% 7% 5% 7% 8% 22%	3087
August	1st to 10th	Night	7% 5% 3 7% 6% 5% 5% 5% 8% 13% 35%	2825
	11th to 20th	Night	13% 7% 2 7% 5% 4 4 3 6% 8% 41%	2873
	21st to end	Night	7% 4 2 5% 4 5% 5% 5% 7% 10% 47%	3476
September	1st to 10th	Night	9% 7% 2 7% 5% 5% 6% 4 8% 8% 38%	2080
	11th to 20th	Night	11% 7% 2 6% 5% 5% 5% 5% 6% 7% 40%	2090
	21st to end	Night	10% 6% 2 6% 4 4 5% 4 6% 7% 46%	2090
October	1st to 10th	Night	11% 7% 2 5% 3 2 3 3 4 6% 54%	2090
	11th to 20th	Night	13% 5% 3 5% 4 4 3 3 4 6% 50%	2238
	21st to end	Night	11% 7% 2 5% 4 3 3 3 4 5% 54%	2508
November	1st to 10th	Night	11% 6% 2 5% 3 3 3 3 5% 7% 52%	2400
	11th to 20th	Night	14% 8% 2 5% 4 3 4 3 4 6% 48%	2470
	21st to end	Night	16% 9% 2 6% 4 3 4 3 6% 6% 42%	2470
December	1st to 10th	Night	22% 9% 3 6% 4 4 4 4 6% 5% 34%	2470
	11th to 20th	Night	15% 11% 4 7% 3 3 3 3 4 6% 41%	3042
	21st to end	Night	17% 12% 6% 9% 5% 4 4 4 5% 7% 26%	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	27% 42% 2 8% 17% 5%	2837
	11th to 20th	Day	24% 45% 3 8% 16% 5%	2840
	21st to end	Day	30% 42% 3 8% 14% 4	3124
February	1st to 10th	Day	18% 65% 3 6% 7% 2	1897
	11th to 20th	Day	20% 64% 2 5% 7% 2	1858
	21st to end	Day	19% 65% 2 4 7% 3	1570
March	1st to 10th	Day	34% 40% 5% 9% 6% 6%	3263
	11th to 20th	Day	18% 40% 3 14% 16% 8%	3480
	21st to end	Day	27% 40% 4 15% 9% 4	3815
April	1st to 10th	Day	18% 65% 3 5% 7% 1	2111
	11th to 20th	Day	18% 66% 4 6% 5% 1	2271
	21st to end	Day	14% 65% 5% 9% 6% 1	2470
May	1st to 10th	Day	30% 41% 9% 13% 7% 1	4120
	11th to 20th	Day	34% 42% 6% 15% 3	4085
	21st to end	Day	26% 41% 9% 14% 10%	4489
June	1st to 10th	Day	19% 67% 5% 7% 2	2470
	11th to 20th	Day	15% 68% 7% 6% 4	2470
	21st to end	Day	17% 66% 7% 7% 3	2470
July	1st to 10th	Day	26% 45% 14% 13% 2	4055
	11th to 20th	Day	28% 45% 15% 10% 2	4051
	21st to end	Day	49% 39% 6% 4 2	4324
August	1st to 10th	Day	26% 43% 13% 15% 4	4091
	11th to 20th	Day	18% 44% 17% 10% 9% 2	3990
	21st to end	Day	18% 42% 10% 20% 9% 1	4156
September	1st to 10th	Day	17% 62% 5% 8% 7% 1	2090
	11th to 20th	Day	19% 62% 5% 8% 6%	2090
	21st to end	Day	18% 62% 7% 7% 6% 1	2090
October	1st to 10th	Day	16% 61% 5% 7% 9% 2	2090
	11th to 20th	Day	13% 61% 3 8% 8% 7%	1939
	21st to end	Day	15% 58% 2 9% 11% 5%	2090
November	1st to 10th	Day	18% 58% 2 6% 11% 4	1719
	11th to 20th	Day	15% 59% 3 9% 10% 4	1710
	21st to end	Day	16% 60% 3 7% 11% 2	1710
December	1st to 10th	Day	23% 60% 2 7% 5% 2	1710
	11th to 20th	Day	20% 49% 3 6% 16% 6%	2150
	21st to end	Day	27% 44% 3 13% 11% 2	3124
January	1st to 10th	Night	30% 38% 2 6% 19% 5%	4109
	11th to 20th	Night	25% 40% 3 11% 13% 8%	4120
	21st to end	Night	32% 43% 3 5% 12% 5%	4532
February	1st to 10th	Night	16% 65% 4 6% 7% 2	2280
	11th to 20th	Night	21% 63% 2 6% 6% 2	2219
	21st to end	Night	19% 65% 3 5% 4 3	1884
March	1st to 10th	Night	35% 45% 5% 6% 6% 2	3588
	11th to 20th	Night	17% 41% 5% 15% 14% 8%	3480
	21st to end	Night	28% 41% 5% 12% 10% 5%	3817
April	1st to 10th	Night	15% 65% 5% 6% 7% 1	2084
	11th to 20th	Night	17% 66% 4 6% 5% 2	1856
	21st to end	Night	13% 66% 4 11% 5% 1	1710
May	1st to 10th	Night	30% 42% 10% 14% 4 1	2840
	11th to 20th	Night	30% 43% 7% 14% 6%	2813
	21st to end	Night	20% 43% 12% 16% 8%	3087
June	1st to 10th	Night	16% 67% 6% 6% 3 1	1710
	11th to 20th	Night	11% 68% 9% 9% 3	1710
	21st to end	Night	14% 65% 9% 9% 3	1710
July	1st to 10th	Night	27% 43% 16% 13% 1	2795
	11th to 20th	Night	22% 44% 18% 14% 1	2786
	21st to end	Night	44% 41% 7% 5% 2	2988
August	1st to 10th	Night	25% 41% 19% 13% 2	2814
	11th to 20th	Night	22% 43% 16% 11% 8%	2900
	21st to end	Night	12% 42% 14% 24% 8% 1	3476
September	1st to 10th	Night	16% 62% 6% 8% 7% 1	2080
	11th to 20th	Night	15% 64% 6% 8% 6%	2090
	21st to end	Night	16% 62% 7% 8% 6% 1	2090
October	1st to 10th	Night	14% 61% 5% 8% 9% 2	2090
	11th to 20th	Night	14% 61% 4 8% 8% 5%	2238
	21st to end	Night	13% 59% 2 9% 12% 5%	2508
November	1st to 10th	Night	19% 59% 4 8% 8% 3	2400
	11th to 20th	Night	16% 61% 3 7% 9% 5%	2470
	21st to end	Night	17% 60% 4 9% 10% 1	2470
December	1st to 10th	Night	23% 60% 3 6% 5% 2	2470
	11th to 20th	Night	18% 52% 2 7% 16% 5%	3044
	21st to end	Night	34% 42% 5% 9% 9% 1	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	33% 23% 33% 9% 2	270
	11th to 20th	Day	38% 21% 23% 14% 4	270
	21st to end	Day	33% 27% 28% 9% 3	297
February	1st to 10th	Day	33% 23% 31% 11% 1	270
	11th to 20th	Day	44% 24% 25% 6% 1	270
	21st to end	Day	43% 25% 25% 6%	225
March	1st to 10th	Day	32% 17% 29% 17% 6%	348
	11th to 20th	Day	30% 18% 25% 20% 6% 1	460
	21st to end	Day	28% 21% 26% 19% 6% 1	506
April	1st to 10th	Day	26% 17% 27% 20% 10% 1	460
	11th to 20th	Day	20% 23% 21% 23% 10% 2	452
	21st to end	Day	23% 15% 22% 23% 14% 3	460
May	1st to 10th	Day	21% 20% 23% 20% 12% 5%	463
	11th to 20th	Day	18% 12% 23% 23% 16% 9%	487
	21st to end	Day	16% 8% 24% 22% 17% 13%	529
June	1st to 10th	Day	16% 5% 21% 26% 21% 11%	490
	11th to 20th	Day	9% 5% 20% 25% 23% 17%	490
	21st to end	Day	14% 5% 24% 25% 19% 14%	490
July	1st to 10th	Day	12% 5% 14% 26% 26% 17%	485
	11th to 20th	Day	10% 4 14% 26% 24% 22%	484
	21st to end	Day	12% 4 13% 23% 26% 22%	532
August	1st to 10th	Day	19% 5% 17% 21% 19% 19%	486
	11th to 20th	Day	16% 5% 14% 24% 25% 15%	479
	21st to end	Day	16% 2 14% 22% 28% 19%	539
September	1st to 10th	Day	12% 4 13% 25% 32% 14%	490
	11th to 20th	Day	17% 7% 14% 22% 29% 12%	490
	21st to end	Day	17% 8% 15% 27% 25% 8%	490
October	1st to 10th	Day	15% 7% 20% 30% 20% 8%	490
	11th to 20th	Day	17% 13% 24% 24% 19% 3	490
	21st to end	Day	20% 12% 24% 26% 16% 2	539
November	1st to 10th	Day	21% 12% 30% 24% 10% 4	305
	11th to 20th	Day	22% 21% 30% 19% 7%	270
	21st to end	Day	20% 20% 34% 18% 7% 1	270
December	1st to 10th	Day	36% 17% 29% 14% 3 1	270
	11th to 20th	Day	30% 17% 30% 18% 5% 1	270
	21st to end	Day	32% 19% 33% 12% 4	297
January	1st to 10th	Night	30% 13% 27% 24% 5%	760
	11th to 20th	Night	29% 16% 24% 24% 7%	760
	21st to end	Night	25% 17% 30% 26% 3	836
February	1st to 10th	Night	23% 15% 27% 30% 5%	760
	11th to 20th	Night	30% 17% 29% 22% 2	743
	21st to end	Night	33% 18% 27% 18% 4	628
March	1st to 10th	Night	23% 17% 29% 27% 4	760
	11th to 20th	Night	24% 16% 25% 25% 9% 1	760
	21st to end	Night	24% 15% 26% 27% 8% 1	836
April	1st to 10th	Night	21% 14% 26% 28% 10% 1	754
	11th to 20th	Night	21% 11% 21% 30% 15% 1	563
	21st to end	Night	14% 10% 22% 36% 17% 2	570
May	1st to 10th	Night	16% 10% 20% 31% 21% 2	570
	11th to 20th	Night	17% 6% 14% 31% 26% 5%	561
	21st to end	Night	14% 3 10% 33% 34% 7%	617
June	1st to 10th	Night	13% 4 10% 33% 33% 7%	570
	11th to 20th	Night	7% 3 12% 32% 33% 14%	570
	21st to end	Night	11% 2 7% 30% 41% 8%	570
July	1st to 10th	Night	12% 2 7% 23% 46% 10%	555
	11th to 20th	Night	11% 3 7% 20% 44% 15%	552
	21st to end	Night	11% 3 5% 22% 44% 15%	624
August	1st to 10th	Night	12% 3 6% 25% 43% 11%	567
	11th to 20th	Night	13% 2 9% 28% 39% 9%	564
	21st to end	Night	12% 3 7% 23% 43% 13%	627
September	1st to 10th	Night	13% 3 9% 29% 37% 9%	750
	11th to 20th	Night	15% 5% 12% 26% 36% 6%	760
	21st to end	Night	15% 5% 11% 32% 34% 3	760
October	1st to 10th	Night	16% 6% 15% 30% 26% 7%	760
	11th to 20th	Night	17% 8% 19% 33% 21% 2	760
	21st to end	Night	17% 11% 17% 36% 16% 3	836
November	1st to 10th	Night	16% 8% 18% 33% 21% 4	749
	11th to 20th	Night	21% 12% 18% 33% 14% 2	760
	21st to end	Night	21% 12% 18% 34% 14% 1	760
December	1st to 10th	Night	29% 14% 20% 28% 9% 1	760
	11th to 20th	Night	25% 14% 21% 32% 7% 1	760
	21st to end	Night	31% 11% 21% 31% 5%	836

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