Peddler Hill
Clear Sky Chart
History

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

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	6% 7% 2 4 2 2 2 2 4 5% 63%	105141
	Night	7% 8% 2 4 3 3 3 3 4 5% 60%	102763
Transparency	Day	25% 3 7% 19% 25% 21%	104889
	Night	27% 4 6% 18% 25% 20%	102604
Seeing	Day	14% 17% 33% 23% 10% 3	15168
	Night	13% 8% 21% 34% 20% 4	24526

By Month

Percentage Cloud Cover SW (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	9% 19% 3 6% 3 2 3 2 4 4 44%	2539
	11th to 20th	Day	14% 13% 3 7% 4 4 4 3 4 7% 37%	2700
	21st to end	Day	13% 16% 4 6% 4 4 4 3 4 7% 36%	3146
February	1st to 10th	Day	14% 12% 3 5% 3 2 3 3 4 5% 46%	1710
	11th to 20th	Day	8% 13% 4 6% 4 3 4 2 4 7% 45%	1846
	21st to end	Day	12% 17% 4 6% 3 3 3 3 3 5% 42%	1570
March	1st to 10th	Day	8% 20% 9% 10% 4 4 3 3 4 6% 28%	3138
	11th to 20th	Day	8% 13% 3 4 2 2 2 2 4 5% 54%	3485
	21st to end	Day	9% 24% 5% 7% 3 3 3 2 4 6% 33%	4038
April	1st to 10th	Day	11% 13% 3 5% 3 3 3 3 5% 6% 45%	2280
	11th to 20th	Day	9% 14% 3 5% 3 2 3 3 4 6% 49%	2249
	21st to end	Day	10% 8% 2 3 2 2 3 3 5% 7% 55%	2280
May	1st to 10th	Day	7% 6% 2 3 2 1 2 2 3 5% 67%	3913
	11th to 20th	Day	4 5% 1 2 2 2 2 2 3 5% 71%	4305
	21st to end	Day	6% 5% 1 4 2 2 3 2 4 5% 67%	4813
June	1st to 10th	Day	6% 5% 2 4 3 2 3 3 5% 6% 61%	2660
	11th to 20th	Day	3 3 1 2 2 2 2 2 3 5% 76%	2660
	21st to end	Day	2 2 1 2 1 2 2 2 3 3 79%	2660
July	1st to 10th	Day	1 1 1 1 1 1 1 2 92%	4420
	11th to 20th	Day	2 2 1 2 2 2 2 2 3 4 78%	4420
	21st to end	Day	1 1 1 2 1 1 1 1 2 3 85%	4581
August	1st to 10th	Day	2 2 1 3 1 2 2 2 3 4 79%	4044
	11th to 20th	Day	1 1 1 1 1 2 1 2 3 87%	3724
	21st to end	Day	2 1 1 2 1 1 1 1 2 2 86%	4180
September	1st to 10th	Day	2 1 1 1 1 2 1 3 3 84%	2280
	11th to 20th	Day	3 3 1 3 2 2 2 3 4 4 72%	2264
	21st to end	Day	5% 4 1 2 1 2 2 1 3 4 75%	2090
October	1st to 10th	Day	4 3 1 3 2 2 2 3 4 5% 70%	3190
	11th to 20th	Day	6% 2 1 2 2 2 1 2 3 3 76%	3161
	21st to end	Day	4 6% 1 4 3 3 3 3 4 6% 64%	3425
November	1st to 10th	Day	10% 8% 3 2 3 4 3 3 5% 7% 53%	1764
	11th to 20th	Day	8% 7% 2 4 3 3 4 4 5% 7% 55%	1710
	21st to end	Day	8% 9% 2 4 3 3 3 3 5% 6% 54%	1654
December	1st to 10th	Day	12% 7% 3 5% 3 4 4 3 4 7% 49%	1520
	11th to 20th	Day	18% 13% 5% 7% 4 4 4 2 5% 5% 33%	1928
	21st to end	Day	9% 10% 3 5% 4 4 4 5% 6% 9% 40%	2794
January	1st to 10th	Night	8% 12% 3 7% 3 3 3 3 5% 6% 45%	4406
	11th to 20th	Night	15% 12% 4 6% 4 4 5% 4 5% 6% 34%	4261
	21st to end	Night	11% 17% 3 6% 5% 4 4 3 5% 7% 34%	4521
February	1st to 10th	Night	12% 10% 3 6% 3 3 3 2 4 6% 48%	2470
	11th to 20th	Night	8% 13% 3 6% 3 3 4 3 6% 6% 46%	2220
	21st to end	Night	10% 13% 3 7% 3 2 2 2 4 4 48%	1884
March	1st to 10th	Night	8% 22% 8% 7% 3 3 3 3 5% 5% 34%	3736
	11th to 20th	Night	10% 12% 2 3 2 2 2 2 4 5% 57%	3490
	21st to end	Night	10% 21% 4 6% 4 4 4 3 5% 6% 33%	3614
April	1st to 10th	Night	10% 11% 3 5% 3 3 3 3 5% 6% 48%	1900
	11th to 20th	Night	8% 10% 2 4 4 3 3 3 4 6% 53%	1879
	21st to end	Night	7% 8% 1 3 3 3 3 3 5% 6% 58%	1900
May	1st to 10th	Night	3 4 3 4 2 2 2 3 3 5% 68%	3062
	11th to 20th	Night	3 3 1 2 2 2 2 2 3 6% 74%	2585
	21st to end	Night	4 4 1 2 2 2 2 2 4 5% 73%	2762
June	1st to 10th	Night	6% 5% 1 3 3 3 3 2 4 5% 65%	1520
	11th to 20th	Night	2 1 1 1 1 1 2 2 3 3 82%	1520
	21st to end	Night	3 2 1 1 2 2 2 2 2 3 81%	1520
July	1st to 10th	Night	1 1 1 1 1 1 1 1 92%	2540
	11th to 20th	Night	4 4 1 3 2 2 2 1 2 3 75%	2540
	21st to end	Night	2 1 1 1 2 2 2 2 2 3 82%	2974
August	1st to 10th	Night	3 3 1 2 1 2 3 3 3 4 76%	2895
	11th to 20th	Night	1 1 1 1 1 1 2 2 2 87%	3126
	21st to end	Night	2 1 1 2 1 1 1 1 1 2 87%	3498
September	1st to 10th	Night	2 1 1 1 1 1 1 2 4 87%	1900
	11th to 20th	Night	3 2 2 1 2 2 2 3 5% 78%	1914
	21st to end	Night	3 2 1 2 2 2 2 2 2 5% 77%	2090
October	1st to 10th	Night	3 3 1 2 2 2 2 2 3 3 77%	3787
	11th to 20th	Night	3 2 1 3 1 2 2 2 3 5% 78%	3777
	21st to end	Night	7% 3 1 3 3 3 3 3 4 5% 65%	4141
November	1st to 10th	Night	9% 8% 2 3 2 3 2 2 4 6% 57%	2535
	11th to 20th	Night	7% 5% 1 3 4 3 4 4 4 8% 57%	2476
	21st to end	Night	9% 8% 2 4 3 3 3 3 4 5% 56%	2522
December	1st to 10th	Night	14% 9% 2 4 3 3 3 3 4 6% 49%	2660
	11th to 20th	Night	18% 13% 3 6% 4 3 4 3 5% 7% 33%	3276
	21st to end	Night	10% 12% 4 7% 5% 4 5% 4 6% 7% 37%	4862

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% 9% 19% 19% 5%	2539
	11th to 20th	Day	48% 3 10% 16% 14% 9%	2700
	21st to end	Day	49% 5% 9% 18% 14% 6%	3146
February	1st to 10th	Day	41% 3 8% 19% 17% 12%	1710
	11th to 20th	Day	40% 4 7% 18% 22% 9%	1856
	21st to end	Day	46% 4 6% 19% 18% 7%	1570
March	1st to 10th	Day	55% 6% 10% 13% 10% 6%	3138
	11th to 20th	Day	33% 3 10% 29% 21% 4	3485
	21st to end	Day	50% 7% 12% 20% 9% 2	4038
April	1st to 10th	Day	39% 4 14% 21% 18% 4	2280
	11th to 20th	Day	35% 6% 12% 25% 17% 6%	2252
	21st to end	Day	28% 4 15% 30% 20% 3	2280
May	1st to 10th	Day	21% 4 12% 29% 22% 13%	3913
	11th to 20th	Day	17% 3 7% 34% 31% 8%	4308
	21st to end	Day	19% 6% 10% 40% 22% 3	4814
June	1st to 10th	Day	24% 5% 10% 26% 27% 8%	2660
	11th to 20th	Day	13% 4 8% 24% 35% 17%	2660
	21st to end	Day	11% 3 4 15% 35% 33%	2660
July	1st to 10th	Day	4 1 1 7% 17% 71%	4351
	11th to 20th	Day	9% 2 4 11% 17% 57%	4345
	21st to end	Day	7% 2 2 8% 30% 50%	4436
August	1st to 10th	Day	11% 2 2 9% 30% 46%	4029
	11th to 20th	Day	5% 2 2 7% 38% 46%	3760
	21st to end	Day	8% 1 2 11% 43% 35%	4179
September	1st to 10th	Day	8% 2 2 10% 38% 41%	2280
	11th to 20th	Day	15% 3 4 21% 38% 18%	2264
	21st to end	Day	15% 3 4 21% 35% 23%	2090
October	1st to 10th	Day	17% 3 4 10% 35% 31%	3190
	11th to 20th	Day	16% 2 4 20% 40% 19%	3161
	21st to end	Day	22% 3 5% 23% 33% 14%	3425
November	1st to 10th	Day	32% 4 7% 22% 23% 13%	1764
	11th to 20th	Day	29% 4 10% 18% 26% 13%	1710
	21st to end	Day	31% 4 7% 20% 27% 12%	1654
December	1st to 10th	Day	36% 4 8% 18% 21% 12%	1520
	11th to 20th	Day	54% 5% 6% 13% 14% 9%	1928
	21st to end	Day	38% 5% 13% 19% 16% 8%	2794
January	1st to 10th	Night	39% 4 10% 25% 17% 5%	4406
	11th to 20th	Night	49% 6% 8% 13% 15% 10%	4261
	21st to end	Night	49% 6% 9% 14% 14% 8%	4521
February	1st to 10th	Night	39% 3 6% 18% 19% 14%	2470
	11th to 20th	Night	38% 4 8% 19% 21% 11%	2221
	21st to end	Night	40% 4 7% 21% 20% 8%	1884
March	1st to 10th	Night	52% 4 9% 13% 15% 7%	3736
	11th to 20th	Night	32% 3 6% 26% 28% 5%	3490
	21st to end	Night	50% 7% 9% 20% 12% 3	3614
April	1st to 10th	Night	36% 6% 11% 21% 19% 6%	1900
	11th to 20th	Night	32% 6% 11% 25% 18% 8%	1879
	21st to end	Night	26% 5% 10% 34% 19% 5%	1900
May	1st to 10th	Night	18% 5% 11% 30% 26% 10%	3062
	11th to 20th	Night	13% 3 7% 23% 40% 14%	2585
	21st to end	Night	14% 4 11% 38% 30% 3	2762
June	1st to 10th	Night	21% 5% 10% 24% 28% 11%	1520
	11th to 20th	Night	9% 3 6% 27% 36% 20%	1520
	21st to end	Night	11% 2 4 14% 34% 35%	1520
July	1st to 10th	Night	4 1 1 6% 18% 71%	2500
	11th to 20th	Night	16% 2 3 8% 15% 55%	2492
	21st to end	Night	9% 2 2 9% 25% 53%	2881
August	1st to 10th	Night	13% 2 3 8% 28% 46%	2886
	11th to 20th	Night	6% 2 2 7% 32% 51%	3156
	21st to end	Night	8% 1 1 12% 38% 39%	3498
September	1st to 10th	Night	6% 1 2 9% 38% 44%	1900
	11th to 20th	Night	11% 2 5% 22% 38% 21%	1914
	21st to end	Night	12% 3 3 23% 34% 25%	2090
October	1st to 10th	Night	14% 2 4 11% 32% 38%	3787
	11th to 20th	Night	12% 2 3 21% 41% 21%	3777
	21st to end	Night	22% 3 5% 19% 34% 17%	4141
November	1st to 10th	Night	29% 4 7% 21% 23% 17%	2535
	11th to 20th	Night	26% 5% 7% 21% 28% 13%	2476
	21st to end	Night	31% 3 5% 20% 24% 16%	2522
December	1st to 10th	Night	37% 3 7% 17% 21% 15%	2660
	11th to 20th	Night	51% 4 5% 12% 19% 8%	3276
	21st to end	Night	44% 5% 10% 14% 17% 9%	4862

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	36% 18% 22% 16% 7% 1	180
	11th to 20th	Day	24% 15% 26% 20% 12% 3	275
	21st to end	Day	22% 15% 26% 22% 12% 3	407
February	1st to 10th	Day	28% 18% 25% 18% 9% 3	370
	11th to 20th	Day	22% 22% 30% 17% 8% 1	453
	21st to end	Day	25% 20% 33% 16% 5% 1	382
March	1st to 10th	Day	33% 25% 23% 13% 5% 1	460
	11th to 20th	Day	29% 21% 22% 16% 10% 2	460
	21st to end	Day	29% 23% 28% 15% 5%	506
April	1st to 10th	Day	22% 23% 30% 17% 7% 1	460
	11th to 20th	Day	25% 21% 25% 21% 6% 2	452
	21st to end	Day	15% 19% 28% 23% 10% 4	460
May	1st to 10th	Day	17% 22% 30% 19% 8% 3	463
	11th to 20th	Day	18% 19% 27% 21% 12% 3	488
	21st to end	Day	17% 15% 26% 22% 16% 4	529
June	1st to 10th	Day	10% 17% 34% 22% 12% 6%	490
	11th to 20th	Day	8% 23% 36% 21% 9% 4	490
	21st to end	Day	3 18% 37% 26% 11% 6%	490
July	1st to 10th	Day	2 8% 51% 21% 12% 5%	486
	11th to 20th	Day	1 9% 44% 30% 11% 5%	484
	21st to end	Day	3 8% 43% 27% 12% 7%	531
August	1st to 10th	Day	4 14% 44% 23% 12% 4	487
	11th to 20th	Day	3 14% 40% 28% 11% 5%	477
	21st to end	Day	4 9% 44% 28% 12% 3	539
September	1st to 10th	Day	3 12% 45% 25% 13% 2	490
	11th to 20th	Day	8% 17% 36% 29% 8% 2	490
	21st to end	Day	8% 15% 36% 33% 7% 1	490
October	1st to 10th	Day	8% 18% 29% 33% 10% 2	490
	11th to 20th	Day	10% 14% 31% 29% 12% 3	490
	21st to end	Day	12% 18% 30% 26% 12% 4	528
November	1st to 10th	Day	19% 15% 21% 24% 16% 5%	300
	11th to 20th	Day	14% 13% 26% 28% 11% 7%	270
	21st to end	Day	14% 16% 28% 23% 14% 4	243
December	1st to 10th	Day	21% 16% 24% 18% 14% 7%	180
	11th to 20th	Day	17% 21% 27% 18% 14% 3	180
	21st to end	Day	25% 13% 26% 21% 12% 3	198
January	1st to 10th	Night	22% 12% 23% 23% 15% 6%	760
	11th to 20th	Night	18% 12% 27% 30% 10% 3	760
	21st to end	Night	21% 12% 25% 23% 16% 4	836
February	1st to 10th	Night	20% 13% 22% 28% 14% 3	760
	11th to 20th	Night	20% 12% 21% 28% 14% 5%	744
	21st to end	Night	22% 10% 25% 30% 11% 2	628
March	1st to 10th	Night	24% 13% 24% 25% 12% 2	760
	11th to 20th	Night	20% 11% 23% 24% 19% 4	760
	21st to end	Night	20% 11% 28% 29% 11% 1	836
April	1st to 10th	Night	17% 8% 24% 34% 14% 2	760
	11th to 20th	Night	14% 12% 25% 31% 15% 3	751
	21st to end	Night	12% 9% 24% 32% 18% 5%	760
May	1st to 10th	Night	10% 10% 24% 32% 20% 4	694
	11th to 20th	Night	7% 8% 19% 39% 24% 3	417
	21st to end	Night	9% 5% 18% 36% 27% 4	411
June	1st to 10th	Night	7% 4 18% 40% 26% 4	380
	11th to 20th	Night	2 5% 21% 42% 28% 3	380
	21st to end	Night	3 4 16% 43% 31% 3	380
July	1st to 10th	Night	1 12% 43% 41% 3	370
	11th to 20th	Night	2 2 14% 44% 34% 4	368
	21st to end	Night	3 1 11% 33% 43% 10%	541
August	1st to 10th	Night	4 1 12% 46% 32% 5%	588
	11th to 20th	Night	2 1 16% 46% 29% 6%	752
	21st to end	Night	3 1 11% 48% 34% 3	836
September	1st to 10th	Night	2 2 14% 46% 32% 4	760
	11th to 20th	Night	4 4 17% 38% 29% 8%	760
	21st to end	Night	4 4 21% 38% 25% 8%	760
October	1st to 10th	Night	7% 7% 18% 41% 20% 6%	760
	11th to 20th	Night	8% 8% 19% 37% 23% 5%	760
	21st to end	Night	9% 9% 21% 31% 20% 10%	836
November	1st to 10th	Night	13% 8% 18% 35% 20% 5%	780
	11th to 20th	Night	13% 9% 25% 33% 16% 5%	762
	21st to end	Night	15% 12% 25% 29% 15% 4	760
December	1st to 10th	Night	20% 10% 23% 30% 12% 4	760
	11th to 20th	Night	24% 11% 21% 29% 13% 3	760
	21st to end	Night	25% 14% 23% 25% 11% 2	836

Page generated at 2024-11-08 03:44:45. Version ac07

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