Kennett
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kennett clear sky chart from 2005-11-06 to 2024-12-09.

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 6% 4 4 4 4 5% 8% 45%	101246
	Night	13% 5% 2 5% 4 3 4 3 5% 7% 49%	98559
Transparency	Day	36% 6% 11% 25% 19% 4	104907
	Night	34% 5% 10% 25% 21% 5%	103039
Seeing	Day	14% 7% 22% 26% 22% 10%	15531
	Night	15% 6% 25% 33% 18% 2	25340

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% 9% 3 8% 4 3 2 3 4 6% 44%	2563
	11th to 20th	Day	17% 9% 3 6% 3 2 3 2 3 5% 46%	2850
	21st to end	Day	25% 9% 2 5% 2 3 3 2 4 6% 38%	3135
February	1st to 10th	Day	18% 9% 3 6% 4 3 4 3 5% 6% 39%	1793
	11th to 20th	Day	18% 10% 3 6% 5% 3 4 3 5% 6% 39%	1848
	21st to end	Day	21% 9% 4 6% 4 4 4 4 6% 5% 34%	1570
March	1st to 10th	Day	19% 11% 3 7% 4 4 4 3 5% 5% 36%	3147
	11th to 20th	Day	14% 7% 2 5% 4 3 3 3 5% 6% 48%	3480
	21st to end	Day	12% 7% 3 7% 5% 5% 5% 4 5% 7% 40%	4037
April	1st to 10th	Day	12% 6% 3 6% 4 3 4 3 5% 7% 48%	2280
	11th to 20th	Day	15% 7% 2 6% 4 3 4 4 6% 6% 42%	2254
	21st to end	Day	16% 7% 3 5% 5% 4 4 4 5% 7% 41%	2280
May	1st to 10th	Day	12% 6% 2 6% 5% 5% 5% 4 7% 10% 36%	3765
	11th to 20th	Day	14% 5% 2 6% 5% 4 5% 5% 6% 11% 37%	4066
	21st to end	Day	11% 6% 3 7% 5% 5% 5% 5% 7% 9% 38%	4824
June	1st to 10th	Day	8% 5% 2 6% 4 5% 4 5% 7% 10% 46%	2660
	11th to 20th	Day	5% 3 1 4 4 5% 5% 5% 7% 11% 49%	2660
	21st to end	Day	4 4 1 5% 4 4 5% 5% 8% 11% 50%	2660
July	1st to 10th	Day	7% 5% 2 5% 4 5% 6% 5% 8% 9% 45%	4440
	11th to 20th	Day	6% 3 1 4 4 3 4 3 6% 10% 55%	4359
	21st to end	Day	11% 7% 3 8% 6% 5% 6% 4 6% 9% 35%	4465
August	1st to 10th	Day	4 2 1 3 3 3 4 3 6% 9% 61%	3894
	11th to 20th	Day	9% 5% 2 6% 3 4 5% 4 5% 8% 49%	3729
	21st to end	Day	5% 3 1 4 3 3 3 3 6% 7% 60%	4180
September	1st to 10th	Day	10% 5% 2 5% 4 5% 4 4 6% 8% 47%	2280
	11th to 20th	Day	13% 5% 2 5% 4 4 3 4 5% 8% 46%	2232
	21st to end	Day	11% 5% 2 4 3 3 4 3 5% 7% 53%	2090
October	1st to 10th	Day	7% 4 1 5% 4 3 3 3 3 7% 60%	1949
	11th to 20th	Day	13% 5% 2 4 3 3 3 3 4 6% 54%	1900
	21st to end	Day	19% 6% 2 4 2 3 3 3 4 5% 50%	2090
November	1st to 10th	Day	11% 6% 2 5% 3 2 3 2 4 6% 55%	1786
	11th to 20th	Day	13% 7% 2 5% 4 3 3 3 3 5% 52%	1800
	21st to end	Day	19% 7% 2 5% 4 3 3 3 4 6% 44%	1800
December	1st to 10th	Day	17% 7% 3 6% 4 3 4 3 5% 6% 42%	1679
	11th to 20th	Day	17% 7% 3 7% 4 4 4 3 4 5% 41%	1918
	21st to end	Day	17% 10% 4 8% 5% 4 4 4 4 6% 34%	2783
January	1st to 10th	Night	18% 6% 2 4 3 3 4 4 5% 6% 44%	4390
	11th to 20th	Night	16% 6% 2 6% 4 3 3 3 4 5% 47%	4120
	21st to end	Night	24% 7% 2 5% 2 2 3 2 4 6% 43%	4532
February	1st to 10th	Night	20% 8% 3 6% 5% 3 3 3 4 5% 41%	2385
	11th to 20th	Night	18% 6% 2 7% 4 4 3 3 5% 5% 44%	2218
	21st to end	Night	18% 7% 2 6% 4 4 4 3 5% 5% 42%	1884
March	1st to 10th	Night	21% 8% 2 6% 3 3 3 2 4 4 42%	3733
	11th to 20th	Night	13% 6% 2 5% 4 3 4 3 4 5% 51%	3480
	21st to end	Night	12% 5% 2 7% 5% 4 4 3 6% 7% 44%	3580
April	1st to 10th	Night	10% 5% 2 6% 4 4 3 4 5% 6% 49%	1900
	11th to 20th	Night	14% 4 2 6% 3 4 3 3 5% 7% 48%	1875
	21st to end	Night	14% 6% 2 6% 4 4 5% 2 4 9% 44%	1900
May	1st to 10th	Night	19% 6% 2 5% 3 3 3 3 4 8% 44%	3130
	11th to 20th	Night	14% 6% 2 6% 3 3 4 3 5% 9% 44%	2810
	21st to end	Night	9% 5% 2 7% 4 5% 5% 5% 7% 10% 41%	2743
June	1st to 10th	Night	8% 5% 2 4 4 5% 4 5% 6% 8% 48%	1520
	11th to 20th	Night	3 3 1 4 4 3 3 3 6% 10% 60%	1520
	21st to end	Night	3 4 1 4 3 3 3 5% 7% 11% 56%	1520
July	1st to 10th	Night	7% 3 1 5% 4 5% 5% 4 8% 11% 47%	2530
	11th to 20th	Night	4 4 1 4 3 3 4 3 6% 9% 60%	2593
	21st to end	Night	9% 7% 4 8% 5% 5% 5% 4 5% 7% 40%	3098
August	1st to 10th	Night	3 2 1 3 3 3 4 3 6% 8% 64%	3035
	11th to 20th	Night	6% 3 2 4 3 4 4 4 6% 9% 53%	3100
	21st to end	Night	4 3 1 4 3 4 3 3 6% 10% 58%	3476
September	1st to 10th	Night	9% 5% 1 4 3 3 3 3 5% 7% 57%	1900
	11th to 20th	Night	9% 4 2 6% 4 4 4 3 5% 7% 52%	1928
	21st to end	Night	9% 5% 2 4 4 2 3 3 5% 6% 57%	2090
October	1st to 10th	Night	6% 4 1 4 3 3 3 3 5% 6% 62%	2228
	11th to 20th	Night	13% 4 2 4 3 3 3 2 3 5% 57%	2280
	21st to end	Night	16% 5% 1 5% 3 3 4 2 4 5% 51%	2508
November	1st to 10th	Night	13% 4 2 6% 3 2 2 2 4 5% 56%	2511
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 4 6% 54%	2600
	21st to end	Night	16% 4 2 5% 4 3 3 3 4 6% 50%	2600
December	1st to 10th	Night	19% 7% 2 6% 3 3 3 3 4 6% 45%	2679
	11th to 20th	Night	16% 7% 2 5% 4 4 3 3 4 5% 47%	3279
	21st to end	Night	16% 8% 3 7% 5% 5% 4 3 4 6% 37%	4884

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% 3 7% 28% 17% 2	2564
	11th to 20th	Day	42% 4 8% 30% 15% 1	2850
	21st to end	Day	48% 5% 9% 20% 16% 2	3135
February	1st to 10th	Day	47% 5% 10% 23% 14% 1	1793
	11th to 20th	Day	47% 5% 9% 20% 15% 4	1858
	21st to end	Day	51% 5% 9% 17% 13% 5%	1570
March	1st to 10th	Day	51% 4 8% 14% 15% 8%	3147
	11th to 20th	Day	38% 4 7% 28% 17% 5%	3480
	21st to end	Day	43% 5% 12% 22% 18%	4037
April	1st to 10th	Day	37% 5% 11% 26% 20% 2	2280
	11th to 20th	Day	41% 5% 9% 22% 18% 5%	2254
	21st to end	Day	43% 5% 9% 23% 19% 1	2280
May	1st to 10th	Day	41% 8% 14% 21% 14% 1	3800
	11th to 20th	Day	40% 8% 16% 22% 14% 1	4070
	21st to end	Day	40% 9% 11% 23% 16% 2	4837
June	1st to 10th	Day	32% 7% 14% 24% 20% 2	2660
	11th to 20th	Day	27% 7% 12% 30% 19% 4	2660
	21st to end	Day	26% 8% 15% 26% 21% 5%	2660
July	1st to 10th	Day	33% 7% 15% 26% 16% 2	4371
	11th to 20th	Day	24% 6% 11% 37% 18% 3	4284
	21st to end	Day	45% 8% 13% 26% 8% 1	4325
August	1st to 10th	Day	18% 7% 17% 31% 25% 2	3880
	11th to 20th	Day	34% 6% 16% 24% 18% 2	3765
	21st to end	Day	23% 6% 12% 35% 22% 3	4179
September	1st to 10th	Day	32% 7% 11% 26% 19% 4	2280
	11th to 20th	Day	35% 5% 8% 25% 23% 4	2232
	21st to end	Day	31% 6% 9% 22% 27% 6%	2090
October	1st to 10th	Day	16% 3 6% 16% 44% 15%	3235
	11th to 20th	Day	21% 3 6% 22% 35% 13%	3140
	21st to end	Day	30% 3 5% 28% 30% 5%	3428
November	1st to 10th	Day	31% 4 9% 26% 23% 7%	1786
	11th to 20th	Day	36% 3 6% 24% 25% 6%	1800
	21st to end	Day	43% 4 7% 22% 21% 3	1800
December	1st to 10th	Day	44% 4 8% 25% 16% 2	1679
	11th to 20th	Day	46% 4 8% 24% 16% 2	1915
	21st to end	Day	51% 5% 9% 21% 12% 2	2783
January	1st to 10th	Night	41% 5% 6% 29% 18% 2	4390
	11th to 20th	Night	40% 5% 8% 25% 18% 4	4120
	21st to end	Night	44% 4 9% 24% 16% 2	4532
February	1st to 10th	Night	46% 3 8% 22% 18% 2	2385
	11th to 20th	Night	42% 5% 9% 22% 18% 4	2219
	21st to end	Night	44% 4 8% 21% 17% 6%	1884
March	1st to 10th	Night	46% 4 8% 15% 18% 9%	3733
	11th to 20th	Night	36% 5% 9% 24% 19% 8%	3480
	21st to end	Night	38% 6% 10% 28% 17% 1	3580
April	1st to 10th	Night	34% 5% 10% 25% 21% 5%	1900
	11th to 20th	Night	36% 5% 7% 23% 21% 8%	1875
	21st to end	Night	38% 6% 8% 26% 19% 3	1900
May	1st to 10th	Night	40% 6% 13% 26% 13% 2	3160
	11th to 20th	Night	37% 8% 16% 23% 15% 2	2811
	21st to end	Night	34% 9% 13% 25% 17% 2	2751
June	1st to 10th	Night	32% 7% 13% 24% 23% 2	1520
	11th to 20th	Night	21% 5% 13% 31% 24% 6%	1520
	21st to end	Night	21% 7% 15% 30% 19% 7%	1520
July	1st to 10th	Night	29% 8% 18% 26% 17% 3	2490
	11th to 20th	Night	21% 5% 13% 36% 21% 4	2545
	21st to end	Night	43% 6% 14% 23% 13% 1	2999
August	1st to 10th	Night	17% 5% 16% 37% 24% 2	3025
	11th to 20th	Night	25% 6% 17% 28% 21% 2	3130
	21st to end	Night	21% 5% 11% 33% 27% 3	3476
September	1st to 10th	Night	27% 5% 10% 28% 22% 7%	1900
	11th to 20th	Night	31% 5% 8% 24% 25% 5%	1928
	21st to end	Night	28% 5% 9% 21% 28% 7%	2090
October	1st to 10th	Night	14% 3 5% 18% 37% 22%	3722
	11th to 20th	Night	21% 2 4 15% 38% 19%	3779
	21st to end	Night	26% 3 5% 26% 29% 11%	4120
November	1st to 10th	Night	31% 3 7% 25% 27% 7%	2511
	11th to 20th	Night	31% 3 6% 24% 26% 10%	2600
	21st to end	Night	36% 3 8% 25% 23% 4	2600
December	1st to 10th	Night	41% 3 9% 24% 19% 4	2679
	11th to 20th	Night	40% 4 7% 25% 21% 3	3281
	21st to end	Night	47% 6% 10% 20% 14% 3	4884

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	27% 10% 34% 21% 6% 1	270
	11th to 20th	Day	30% 11% 37% 17% 4	270
	21st to end	Day	20% 11% 44% 19% 7%	297
February	1st to 10th	Day	25% 14% 34% 19% 7% 1	270
	11th to 20th	Day	27% 17% 32% 19% 3 1	270
	21st to end	Day	32% 16% 33% 14% 5%	225
March	1st to 10th	Day	21% 14% 33% 24% 8%	270
	11th to 20th	Day	23% 16% 34% 24% 3	270
	21st to end	Day	21% 14% 33% 22% 9% 1	430
April	1st to 10th	Day	15% 12% 35% 26% 11%	460
	11th to 20th	Day	19% 12% 32% 26% 10% 1	452
	21st to end	Day	18% 11% 33% 24% 10% 4	460
May	1st to 10th	Day	15% 11% 28% 31% 12% 3	463
	11th to 20th	Day	14% 6% 22% 30% 19% 10%	487
	21st to end	Day	10% 4 22% 29% 25% 10%	734
June	1st to 10th	Day	10% 3 15% 27% 28% 17%	680
	11th to 20th	Day	5% 2 12% 37% 32% 12%	680
	21st to end	Day	4 1 19% 33% 28% 14%	680
July	1st to 10th	Day	8% 1 11% 25% 32% 23%	671
	11th to 20th	Day	6% 2 9% 27% 37% 19%	668
	21st to end	Day	9% 1 10% 27% 34% 19%	739
August	1st to 10th	Day	8% 2 7% 31% 36% 17%	557
	11th to 20th	Day	15% 1 10% 25% 35% 14%	479
	21st to end	Day	9% 1 7% 19% 39% 26%	539
September	1st to 10th	Day	10% 2 9% 25% 37% 17%	490
	11th to 20th	Day	11% 3 9% 21% 33% 23%	490
	21st to end	Day	16% 4 14% 28% 26% 13%	490
October	1st to 10th	Day	8% 3 17% 35% 30% 8%	349
	11th to 20th	Day	11% 8% 32% 24% 18% 7%	300
	21st to end	Day	22% 11% 28% 22% 14% 3	330
November	1st to 10th	Day	14% 8% 26% 30% 18% 4	300
	11th to 20th	Day	11% 8% 38% 28% 13% 2	300
	21st to end	Day	22% 11% 33% 21% 12% 2	300
December	1st to 10th	Day	17% 12% 37% 23% 9% 2	294
	11th to 20th	Day	25% 11% 30% 20% 11% 2	270
	21st to end	Day	25% 15% 35% 21% 3 1	297
January	1st to 10th	Night	22% 8% 36% 28% 5%	950
	11th to 20th	Night	23% 11% 37% 25% 3 1	950
	21st to end	Night	20% 10% 37% 30% 3	1045
February	1st to 10th	Night	24% 8% 36% 29% 4	865
	11th to 20th	Night	22% 10% 40% 26% 2	743
	21st to end	Night	21% 15% 38% 24% 2	628
March	1st to 10th	Night	20% 11% 32% 31% 5%	760
	11th to 20th	Night	19% 12% 34% 29% 5% 1	570
	21st to end	Night	19% 10% 34% 29% 9%	627
April	1st to 10th	Night	13% 9% 42% 29% 7% 1	570
	11th to 20th	Night	15% 9% 33% 32% 11%	563
	21st to end	Night	16% 7% 32% 35% 9% 1	570
May	1st to 10th	Night	16% 6% 27% 36% 14% 1	570
	11th to 20th	Night	15% 5% 23% 39% 17% 2	561
	21st to end	Night	7% 3 19% 41% 26% 3	617
June	1st to 10th	Night	9% 1 14% 40% 31% 4	570
	11th to 20th	Night	4 1 13% 44% 36% 2	570
	21st to end	Night	5% 1 11% 45% 35% 4	570
July	1st to 10th	Night	5% 2 8% 34% 44% 8%	555
	11th to 20th	Night	5% 2 8% 30% 47% 8%	552
	21st to end	Night	6% 1 9% 32% 42% 10%	624
August	1st to 10th	Night	4 1 6% 33% 50% 7%	567
	11th to 20th	Night	8% 1 8% 37% 40% 6%	564
	21st to end	Night	6% 1 6% 30% 47% 10%	627
September	1st to 10th	Night	10% 1 6% 34% 41% 7%	570
	11th to 20th	Night	10% 2 9% 33% 40% 7%	598
	21st to end	Night	11% 2 17% 36% 30% 4	760
October	1st to 10th	Night	8% 3 17% 39% 29% 5%	760
	11th to 20th	Night	15% 4 28% 34% 18% 2	760
	21st to end	Night	17% 7% 27% 35% 13% 1	836
November	1st to 10th	Night	15% 5% 26% 37% 16% 1	780
	11th to 20th	Night	15% 7% 31% 36% 11%	800
	21st to end	Night	18% 6% 31% 34% 10% 1	800
December	1st to 10th	Night	22% 8% 29% 33% 7%	893
	11th to 20th	Night	23% 8% 28% 33% 8%	950
	21st to end	Night	24% 10% 33% 28% 4	1045

Page generated at 2024-12-06 02:54:47. Version ac07

Copyright © 2024 Attilla Danko.