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 2026-10-14.

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	14% 8% 3 7% 5% 5% 5% 4 6% 8% 37%	148842
	Night	14% 9% 3 6% 4 4 4 4 5% 7% 39%	142902
Transparency	Day	29% 37% 8% 12% 10% 4	152605
	Night	28% 36% 9% 12% 10% 4	147211
Seeing	Day	21% 13% 23% 21% 15% 7%	17504
	Night	20% 10% 19% 28% 19% 4	27480

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	19% 10% 4 6% 3 2 3 3 4 5% 41%	5258
	11th to 20th	Day	11% 8% 4 7% 3 3 2 2 3 4 53%	5280
	21st to end	Day	20% 11% 4 7% 3 3 3 2 3 5% 38%	5780
February	1st to 10th	Day	18% 10% 3 7% 4 4 4 4 4 5% 38%	2097
	11th to 20th	Day	22% 10% 2 6% 5% 3 4 3 4 5% 35%	2048
	21st to end	Day	23% 9% 2 6% 4 4 3 3 4 6% 36%	1730
March	1st to 10th	Day	20% 9% 3 7% 4 3 4 3 5% 6% 36%	4783
	11th to 20th	Day	13% 6% 2 5% 3 3 3 3 4 6% 50%	5090
	21st to end	Day	17% 8% 3 6% 4 4 4 3 4 5% 43%	5586
April	1st to 10th	Day	13% 7% 3 6% 5% 5% 5% 4 6% 7% 39%	2333
	11th to 20th	Day	13% 7% 2 7% 4 4 4 4 5% 7% 43%	2513
	21st to end	Day	14% 7% 2 6% 6% 4 4 4 5% 8% 41%	2730
May	1st to 10th	Day	18% 9% 3 7% 4 4 5% 4 5% 8% 33%	7616
	11th to 20th	Day	14% 9% 4 9% 6% 5% 5% 4 6% 7% 30%	7626
	21st to end	Day	17% 11% 4 9% 6% 6% 6% 4 6% 7% 25%	8391
June	1st to 10th	Day	12% 7% 3 9% 6% 6% 6% 4 8% 9% 30%	2730
	11th to 20th	Day	7% 6% 2 7% 7% 6% 7% 6% 8% 10% 33%	2730
	21st to end	Day	9% 5% 2 7% 7% 6% 6% 6% 8% 10% 33%	2730
July	1st to 10th	Day	6% 5% 2 7% 6% 7% 7% 6% 9% 12% 33%	7680
	11th to 20th	Day	10% 7% 3 8% 7% 7% 7% 7% 9% 11% 24%	7680
	21st to end	Day	12% 8% 3 9% 7% 7% 7% 6% 8% 10% 23%	8340
August	1st to 10th	Day	9% 8% 3 9% 6% 7% 7% 6% 9% 10% 25%	6014
	11th to 20th	Day	7% 4 2 5% 4 4 6% 5% 8% 14% 42%	5813
	21st to end	Day	7% 4 2 6% 5% 5% 6% 5% 8% 9% 42%	6041
September	1st to 10th	Day	11% 6% 3 9% 6% 6% 5% 5% 7% 7% 34%	2310
	11th to 20th	Day	13% 6% 3 7% 7% 5% 5% 4 6% 8% 36%	2310
	21st to end	Day	13% 6% 2 7% 4 5% 5% 4 6% 6% 41%	2310
October	1st to 10th	Day	10% 6% 2 5% 4 4 4 3 5% 6% 51%	2310
	11th to 20th	Day	12% 6% 2 4 3 2 4 3 4 5% 54%	2073
	21st to end	Day	14% 6% 2 5% 4 3 3 3 4 6% 52%	2200
November	1st to 10th	Day	12% 5% 2 4 3 4 4 3 4 6% 54%	1882
	11th to 20th	Day	14% 5% 2 4 3 3 4 4 5% 7% 49%	1890
	21st to end	Day	16% 9% 3 4 4 4 3 3 5% 6% 44%	1890
December	1st to 10th	Day	21% 7% 2 4 3 3 3 2 4 5% 46%	3020
	11th to 20th	Day	20% 10% 3 6% 4 4 4 3 5% 5% 36%	3463
	21st to end	Day	16% 10% 5% 7% 3 3 4 3 5% 7% 38%	4565
January	1st to 10th	Night	17% 12% 3 6% 3 3 3 2 4 6% 42%	7635
	11th to 20th	Night	17% 9% 3 6% 3 2 2 2 3 5% 48%	7680
	21st to end	Night	19% 13% 3 6% 3 3 3 2 3 4 40%	8401
February	1st to 10th	Night	16% 10% 3 6% 4 4 3 4 5% 6% 40%	2520
	11th to 20th	Night	21% 11% 3 6% 4 4 4 3 4 4 37%	2458
	21st to end	Night	23% 10% 3 6% 4 4 4 3 4 5% 34%	2076
March	1st to 10th	Night	19% 12% 4 6% 4 4 4 3 4 5% 33%	5288
	11th to 20th	Night	12% 8% 1 5% 3 3 4 3 5% 7% 48%	5090
	21st to end	Night	13% 11% 3 6% 4 4 4 3 5% 6% 42%	5588
April	1st to 10th	Night	14% 8% 2 5% 4 3 5% 3 6% 8% 43%	2303
	11th to 20th	Night	12% 8% 2 6% 4 3 3 2 6% 8% 47%	2054
	21st to end	Night	12% 7% 2 6% 4 4 4 4 6% 7% 44%	1890
May	1st to 10th	Night	17% 9% 3 7% 5% 5% 5% 5% 6% 7% 31%	5237
	11th to 20th	Night	15% 11% 3 8% 5% 4 5% 3 5% 8% 33%	5234
	21st to end	Night	16% 11% 4 8% 6% 5% 6% 5% 5% 8% 27%	5761
June	1st to 10th	Night	10% 8% 2 7% 6% 5% 4 5% 7% 10% 35%	1890
	11th to 20th	Night	7% 6% 2 5% 5% 4 5% 4 7% 10% 43%	1890
	21st to end	Night	8% 6% 2 6% 5% 4 6% 6% 7% 11% 41%	1890
July	1st to 10th	Night	8% 6% 3 7% 5% 5% 6% 4 8% 12% 36%	5278
	11th to 20th	Night	10% 8% 3 8% 5% 6% 6% 6% 9% 12% 28%	5277
	21st to end	Night	14% 9% 3 7% 5% 5% 6% 5% 7% 10% 30%	5736
August	1st to 10th	Night	9% 6% 3 8% 6% 6% 6% 6% 9% 13% 29%	4135
	11th to 20th	Night	9% 5% 2 6% 4 4 4 3 6% 11% 45%	4228
	21st to end	Night	6% 4 2 5% 4 5% 5% 4 7% 12% 46%	5046
September	1st to 10th	Night	10% 7% 2 7% 5% 5% 6% 4 8% 8% 39%	2299
	11th to 20th	Night	11% 6% 2 6% 4 5% 5% 5% 6% 8% 41%	2310
	21st to end	Night	10% 7% 3 6% 4 4 5% 3 6% 7% 45%	2310
October	1st to 10th	Night	11% 7% 2 5% 3 2 4 3 4 5% 53%	2310
	11th to 20th	Night	12% 5% 3 5% 3 4 3 3 4 5% 52%	2391
	21st to end	Night	12% 7% 2 5% 4 3 3 3 4 5% 53%	2640
November	1st to 10th	Night	11% 6% 3 5% 3 3 3 3 5% 7% 51%	2632
	11th to 20th	Night	15% 8% 2 5% 3 3 4 3 4 5% 49%	2730
	21st to end	Night	16% 9% 2 6% 3 3 3 3 5% 6% 43%	2730
December	1st to 10th	Night	20% 9% 2 4 2 3 3 3 4 5% 44%	4380
	11th to 20th	Night	21% 11% 4 6% 3 3 3 3 4 5% 35%	4952
	21st to end	Night	16% 12% 5% 8% 4 3 4 4 5% 6% 33%	6633

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	34% 24% 4 15% 18% 5%	5259
	11th to 20th	Day	22% 25% 3 9% 25% 17%	5280
	21st to end	Day	39% 24% 4 10% 13% 10%	5780
February	1st to 10th	Day	19% 59% 3 9% 8% 2	2097
	11th to 20th	Day	24% 58% 2 7% 7% 2	2058
	21st to end	Day	20% 60% 2 5% 10% 3	1730
March	1st to 10th	Day	38% 29% 4 9% 12% 8%	4783
	11th to 20th	Day	22% 29% 3 13% 16% 17%	5090
	21st to end	Day	31% 29% 5% 20% 12% 5%	5586
April	1st to 10th	Day	20% 60% 4 7% 8% 1	2333
	11th to 20th	Day	18% 60% 5% 9% 7% 1	2513
	21st to end	Day	17% 60% 6% 11% 6% 1	2730
May	1st to 10th	Day	39% 25% 11% 17% 8% 1	7651
	11th to 20th	Day	40% 27% 11% 16% 5% 1	7630
	21st to end	Day	48% 25% 7% 11% 8%	8405
June	1st to 10th	Day	21% 61% 6% 8% 3	2730
	11th to 20th	Day	18% 63% 8% 7% 4	2730
	21st to end	Day	18% 62% 9% 8% 3	2730
July	1st to 10th	Day	29% 32% 19% 16% 4	7615
	11th to 20th	Day	39% 35% 17% 8% 1	7611
	21st to end	Day	44% 28% 12% 10% 5% 1	8156
August	1st to 10th	Day	38% 36% 12% 11% 3	6001
	11th to 20th	Day	16% 35% 23% 17% 7% 1	5852
	21st to end	Day	20% 34% 13% 22% 10% 1	6041
September	1st to 10th	Day	19% 57% 6% 9% 8% 1	2310
	11th to 20th	Day	19% 58% 6% 10% 6%	2310
	21st to end	Day	20% 57% 7% 8% 7% 1	2310
October	1st to 10th	Day	15% 36% 5% 12% 23% 8%	3700
	11th to 20th	Day	10% 36% 2 11% 18% 23%	3339
	21st to end	Day	16% 38% 5% 17% 14% 11%	3538
November	1st to 10th	Day	19% 54% 3 8% 12% 4	1882
	11th to 20th	Day	16% 54% 3 11% 12% 4	1890
	21st to end	Day	18% 55% 4 8% 13% 2	1890
December	1st to 10th	Day	26% 35% 3 11% 18% 8%	3020
	11th to 20th	Day	34% 32% 3 10% 15% 6%	3460
	21st to end	Day	31% 31% 7% 19% 11% 1	4565
January	1st to 10th	Night	33% 23% 9% 12% 17% 6%	7636
	11th to 20th	Night	29% 22% 3 12% 21% 13%	7680
	21st to end	Night	35% 25% 5% 9% 16% 9%	8401
February	1st to 10th	Night	18% 60% 4 9% 8% 2	2520
	11th to 20th	Night	24% 57% 2 7% 7% 2	2459
	21st to end	Night	21% 59% 3 6% 6% 4	2076
March	1st to 10th	Night	37% 33% 5% 9% 12% 4	5288
	11th to 20th	Night	21% 30% 4 14% 16% 15%	5090
	21st to end	Night	32% 29% 7% 17% 11% 5%	5588
April	1st to 10th	Night	18% 60% 6% 7% 7% 2	2303
	11th to 20th	Night	17% 60% 5% 10% 7% 1	2054
	21st to end	Night	16% 61% 5% 12% 6% 1	1890
May	1st to 10th	Night	41% 26% 10% 16% 5% 1	5264
	11th to 20th	Night	39% 26% 12% 14% 8%	5235
	21st to end	Night	45% 27% 9% 12% 6%	5771
June	1st to 10th	Night	19% 62% 7% 8% 4 1	1890
	11th to 20th	Night	15% 63% 10% 10% 3	1890
	21st to end	Night	14% 61% 10% 10% 4	1890
July	1st to 10th	Night	29% 30% 23% 16% 2	5235
	11th to 20th	Night	35% 32% 21% 11% 1	5226
	21st to end	Night	41% 27% 16% 11% 4 2	5606
August	1st to 10th	Night	36% 36% 16% 11% 1	4124
	11th to 20th	Night	19% 32% 25% 16% 8%	4255
	21st to end	Night	15% 33% 17% 26% 9%	5046
September	1st to 10th	Night	17% 57% 7% 10% 7% 1	2299
	11th to 20th	Night	16% 59% 8% 11% 7%	2310
	21st to end	Night	18% 57% 8% 8% 8% 1	2310
October	1st to 10th	Night	13% 38% 7% 13% 23% 6%	3700
	11th to 20th	Night	11% 36% 3 11% 19% 19%	3864
	21st to end	Night	16% 38% 5% 15% 16% 11%	4252
November	1st to 10th	Night	20% 55% 4 9% 9% 3	2632
	11th to 20th	Night	17% 55% 3 7% 11% 5%	2730
	21st to end	Night	18% 55% 4 10% 11% 2	2730
December	1st to 10th	Night	27% 35% 3 10% 17% 8%	4380
	11th to 20th	Night	33% 35% 3 9% 15% 5%	4954
	21st to end	Night	35% 31% 8% 15% 11% 1	6633

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	37% 25% 29% 7% 2	330
	11th to 20th	Day	40% 23% 22% 12% 3	330
	21st to end	Day	37% 26% 26% 9% 2	363
February	1st to 10th	Day	31% 26% 33% 9% 1	330
	11th to 20th	Day	46% 25% 23% 5% 1	330
	21st to end	Day	41% 27% 26% 6% 1	273
March	1st to 10th	Day	35% 17% 29% 15% 5%	416
	11th to 20th	Day	32% 18% 26% 18% 5% 1	540
	21st to end	Day	29% 22% 26% 18% 5% 1	594
April	1st to 10th	Day	25% 19% 26% 20% 9% 1	540
	11th to 20th	Day	21% 23% 23% 21% 10% 2	532
	21st to end	Day	23% 15% 24% 23% 13% 3	540
May	1st to 10th	Day	24% 22% 22% 18% 10% 5%	543
	11th to 20th	Day	19% 13% 24% 22% 14% 8%	567
	21st to end	Day	19% 11% 23% 21% 15% 11%	617
June	1st to 10th	Day	16% 6% 21% 26% 19% 10%	570
	11th to 20th	Day	9% 6% 24% 25% 21% 15%	570
	21st to end	Day	13% 5% 24% 25% 20% 13%	570
July	1st to 10th	Day	10% 5% 15% 29% 25% 17%	565
	11th to 20th	Day	9% 5% 14% 27% 24% 20%	564
	21st to end	Day	11% 5% 15% 24% 24% 20%	620
August	1st to 10th	Day	19% 5% 18% 22% 19% 17%	566
	11th to 20th	Day	14% 5% 14% 27% 25% 15%	559
	21st to end	Day	14% 4 16% 23% 26% 17%	627
September	1st to 10th	Day	11% 5% 14% 25% 31% 13%	570
	11th to 20th	Day	14% 6% 14% 24% 31% 11%	570
	21st to end	Day	15% 9% 16% 27% 25% 7%	570
October	1st to 10th	Day	15% 7% 21% 31% 18% 7%	570
	11th to 20th	Day	16% 12% 26% 24% 18% 3	542
	21st to end	Day	22% 12% 24% 25% 15% 2	583
November	1st to 10th	Day	21% 14% 32% 21% 9% 3	360
	11th to 20th	Day	23% 23% 31% 18% 6%	330
	21st to end	Day	23% 23% 32% 15% 6% 1	330
December	1st to 10th	Day	37% 21% 28% 11% 3 1	330
	11th to 20th	Day	32% 18% 29% 16% 4 1	330
	21st to end	Day	31% 20% 33% 12% 4	363
January	1st to 10th	Night	31% 14% 27% 23% 5%	840
	11th to 20th	Night	29% 18% 25% 22% 6%	840
	21st to end	Night	25% 18% 31% 23% 3	924
February	1st to 10th	Night	24% 15% 28% 29% 5%	840
	11th to 20th	Night	31% 18% 29% 20% 2	823
	21st to end	Night	32% 18% 28% 18% 4	692
March	1st to 10th	Night	23% 17% 30% 26% 4	840
	11th to 20th	Night	24% 16% 26% 25% 8% 1	840
	21st to end	Night	23% 16% 28% 25% 8% 1	924
April	1st to 10th	Night	22% 14% 27% 27% 9%	833
	11th to 20th	Night	20% 11% 22% 31% 14% 1	623
	21st to end	Night	15% 10% 22% 35% 16% 2	630
May	1st to 10th	Night	17% 10% 22% 31% 19% 2	630
	11th to 20th	Night	18% 7% 15% 31% 24% 4	621
	21st to end	Night	16% 5% 10% 31% 31% 6%	683
June	1st to 10th	Night	14% 5% 10% 33% 32% 7%	630
	11th to 20th	Night	9% 3 12% 32% 31% 13%	630
	21st to end	Night	11% 3 6% 31% 42% 8%	630
July	1st to 10th	Night	11% 2 7% 24% 46% 9%	615
	11th to 20th	Night	12% 3 7% 20% 44% 14%	612
	21st to end	Night	12% 3 6% 23% 43% 13%	690
August	1st to 10th	Night	13% 4 7% 25% 42% 10%	627
	11th to 20th	Night	14% 2 8% 27% 40% 9%	624
	21st to end	Night	11% 3 9% 26% 40% 12%	693
September	1st to 10th	Night	12% 3 10% 29% 36% 9%	829
	11th to 20th	Night	14% 5% 12% 27% 37% 5%	840
	21st to end	Night	15% 5% 11% 32% 33% 3	840
October	1st to 10th	Night	16% 6% 15% 31% 25% 6%	840
	11th to 20th	Night	17% 8% 18% 34% 21% 2	813
	21st to end	Night	18% 12% 17% 35% 15% 3	880
November	1st to 10th	Night	16% 9% 20% 32% 20% 3	820
	11th to 20th	Night	22% 12% 19% 32% 13% 2	840
	21st to end	Night	24% 13% 18% 32% 13% 1	840
December	1st to 10th	Night	29% 14% 23% 26% 8%	840
	11th to 20th	Night	26% 13% 22% 31% 7% 1	840
	21st to end	Night	32% 11% 22% 30% 5%	924

Page generated at 2026-10-11 05:06:33. Version ac07

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