Rogue River Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rogue River Observatory clear sky chart from 2005-11-06 to 2024-01-17.

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	17% 7% 3 5% 4 2 4 4 4 6% 44%	74723
	Night	19% 8% 3 5% 4 2 4 4 4 6% 42%	75119
Transparency	Day	42% 6% 11% 20% 16% 5%	74438
	Night	44% 6% 10% 19% 15% 6%	74925
Seeing	Day	21% 11% 28% 27% 11% 2	13915
	Night	24% 8% 20% 30% 16% 2	23032

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	30% 14% 4 8% 6% 3 4 3 5% 5% 18%	1519
	11th to 20th	Day	29% 10% 3 6% 4 1 5% 4 4 6% 29%	1672
	21st to end	Day	25% 9% 3 5% 4 2 4 3 5% 6% 32%	1782
February	1st to 10th	Day	26% 9% 4 6% 5% 3 5% 4 5% 7% 26%	1620
	11th to 20th	Day	27% 10% 3 7% 5% 3 4 3 3 5% 29%	1575
	21st to end	Day	31% 12% 5% 6% 4 3 3 3 3 5% 25%	1404
March	1st to 10th	Day	29% 12% 4 8% 6% 3 4 4 4 5% 21%	1980
	11th to 20th	Day	28% 10% 3 6% 7% 3 5% 4 4 6% 23%	1980
	21st to end	Day	30% 11% 3 6% 7% 4 4 4 5% 5% 20%	2178
April	1st to 10th	Day	28% 12% 4 8% 5% 4 5% 3 4 5% 23%	2122
	11th to 20th	Day	26% 10% 4 6% 5% 3 4 4 5% 7% 27%	2146
	21st to end	Day	21% 7% 3 6% 5% 3 4 4 6% 9% 32%	2340
May	1st to 10th	Day	15% 7% 2 4 5% 4 4 4 5% 7% 44%	2340
	11th to 20th	Day	15% 8% 3 6% 4 4 4 5% 6% 8% 37%	2411
	21st to end	Day	18% 6% 3 4 4 3 3 4 6% 9% 39%	2723
June	1st to 10th	Day	18% 6% 2 5% 5% 3 4 5% 5% 7% 40%	2520
	11th to 20th	Day	10% 4 3 4 4 2 3 4 5% 8% 54%	2520
	21st to end	Day	7% 3 1 3 3 2 3 3 4 6% 66%	2520
July	1st to 10th	Day	2 2 1 2 2 1 2 3 3 6% 75%	2520
	11th to 20th	Day	5% 2 1 2 2 1 3 2 3 4 76%	2474
	21st to end	Day	2 1 1 2 1 2 1 2 5% 82%	2546
August	1st to 10th	Day	2 1 1 1 2 2 2 3 4 6% 76%	2328
	11th to 20th	Day	2 2 1 1 2 1 2 2 4 7% 75%	2298
	21st to end	Day	4 2 1 3 2 2 2 3 4 6% 72%	2471
September	1st to 10th	Day	2 2 1 3 3 2 3 3 3 5% 74%	2160
	11th to 20th	Day	9% 4 2 5% 4 3 4 4 5% 7% 54%	2048
	21st to end	Day	10% 4 2 4 3 2 3 3 5% 8% 56%	1959
October	1st to 10th	Day	12% 4 1 4 4 2 4 4 5% 6% 54%	1800
	11th to 20th	Day	17% 6% 2 5% 5% 2 3 4 6% 7% 44%	1800
	21st to end	Day	19% 7% 3 5% 3 2 3 4 4 6% 42%	1980
November	1st to 10th	Day	28% 8% 4 7% 6% 3 4 3 6% 7% 25%	1705
	11th to 20th	Day	25% 10% 3 6% 7% 3 5% 4 6% 8% 24%	1520
	21st to end	Day	23% 10% 3 6% 5% 3 4 4 5% 6% 30%	1520
December	1st to 10th	Day	21% 8% 3 7% 5% 3 5% 4 4 6% 34%	1520
	11th to 20th	Day	30% 11% 3 7% 6% 3 5% 5% 4 5% 21%	1928
	21st to end	Day	32% 13% 4 8% 6% 3 4 4 3 3 20%	2794
January	1st to 10th	Night	32% 12% 4 8% 6% 3 5% 4 4 4 19%	2646
	11th to 20th	Night	31% 9% 3 4 5% 2 4 3 4 5% 30%	2429
	21st to end	Night	25% 9% 4 6% 5% 2 4 4 3 6% 32%	2574
February	1st to 10th	Night	25% 9% 3 4 6% 3 5% 4 6% 7% 28%	2340
	11th to 20th	Night	24% 11% 4 5% 5% 3 4 3 4 5% 32%	2272
	21st to end	Night	27% 13% 3 6% 4 3 4 5% 5% 4 27%	1849
March	1st to 10th	Night	27% 12% 4 7% 5% 3 3 5% 5% 5% 24%	1980
	11th to 20th	Night	26% 12% 3 7% 6% 3 4 3 4 5% 26%	1980
	21st to end	Night	30% 12% 4 6% 5% 2 4 4 4 5% 23%	2178
April	1st to 10th	Night	26% 11% 4 6% 5% 3 4 5% 4 6% 26%	1837
	11th to 20th	Night	23% 12% 3 5% 4 2 4 4 4 6% 33%	1757
	21st to end	Night	21% 7% 3 6% 4 3 4 4 5% 8% 35%	1620
May	1st to 10th	Night	14% 7% 3 3 4 2 3 3 4 7% 49%	1620
	11th to 20th	Night	13% 9% 3 6% 4 3 5% 4 6% 7% 39%	1480
	21st to end	Night	15% 6% 3 4 4 2 3 4 6% 8% 45%	1552
June	1st to 10th	Night	17% 7% 3 5% 4 3 4 4 4 7% 44%	1440
	11th to 20th	Night	8% 4 2 2 2 2 3 3 3 7% 64%	1440
	21st to end	Night	6% 3 2 2 3 1 2 3 2 6% 70%	1440
July	1st to 10th	Night	4 2 1 2 2 1 3 3 2 4 77%	1440
	11th to 20th	Night	3 1 1 2 2 2 2 3 3 5% 76%	1483
	21st to end	Night	1 1 1 1 1 2 2 3 3 85%	1773
August	1st to 10th	Night	1 2 1 2 2 1 3 2 4 5% 78%	1611
	11th to 20th	Night	2 1 1 2 2 2 2 3 3 5% 77%	1602
	21st to end	Night	4 2 1 2 2 1 2 3 3 5% 75%	1885
September	1st to 10th	Night	2 3 1 2 2 1 2 2 4 5% 77%	1800
	11th to 20th	Night	6% 4 1 3 4 2 4 3 4 7% 61%	1908
	21st to end	Night	10% 5% 2 3 3 1 3 3 5% 8% 58%	2000
October	1st to 10th	Night	11% 4 2 3 4 3 3 4 4 8% 54%	2160
	11th to 20th	Night	16% 6% 2 4 3 2 3 4 5% 6% 47%	2160
	21st to end	Night	18% 7% 3 6% 4 3 4 3 3 5% 44%	2376
November	1st to 10th	Night	25% 9% 3 7% 5% 3 4 4 5% 6% 30%	2369
	11th to 20th	Night	27% 11% 4 6% 5% 3 4 4 5% 5% 25%	2660
	21st to end	Night	23% 8% 2 5% 5% 3 4 5% 5% 6% 33%	2660
December	1st to 10th	Night	23% 8% 3 5% 5% 3 4 5% 5% 6% 33%	2660
	11th to 20th	Night	32% 11% 4 6% 5% 3 4 3 5% 7% 21%	3276
	21st to end	Night	31% 11% 4 7% 6% 3 4 4 4 5% 23%	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	70% 5% 9% 7% 6% 2	1519
	11th to 20th	Day	58% 6% 6% 11% 9% 10%	1672
	21st to end	Day	54% 5% 7% 15% 13% 6%	1782
February	1st to 10th	Day	58% 7% 10% 15% 7% 2	1620
	11th to 20th	Day	59% 5% 10% 16% 7% 2	1584
	21st to end	Day	62% 6% 10% 12% 7% 2	1404
March	1st to 10th	Day	66% 7% 9% 13% 5% 1	1980
	11th to 20th	Day	61% 7% 11% 13% 6% 1	1980
	21st to end	Day	66% 8% 11% 11% 4	2178
April	1st to 10th	Day	65% 6% 10% 11% 7% 1	2122
	11th to 20th	Day	57% 8% 11% 14% 8% 2	2149
	21st to end	Day	49% 9% 14% 17% 11% 1	2340
May	1st to 10th	Day	40% 7% 14% 24% 13% 2	2340
	11th to 20th	Day	43% 7% 18% 20% 9% 2	2414
	21st to end	Day	42% 8% 18% 25% 7%	2724
June	1st to 10th	Day	44% 6% 13% 22% 14%	2520
	11th to 20th	Day	30% 8% 15% 33% 12% 2	2520
	21st to end	Day	21% 4 12% 36% 21% 5%	2520
July	1st to 10th	Day	13% 4 11% 30% 29% 13%	2451
	11th to 20th	Day	15% 2 8% 20% 36% 19%	2399
	21st to end	Day	8% 2 5% 27% 46% 13%	2405
August	1st to 10th	Day	11% 4 13% 38% 29% 5%	2312
	11th to 20th	Day	12% 3 11% 32% 34% 9%	2298
	21st to end	Day	15% 3 12% 30% 34% 7%	2471
September	1st to 10th	Day	15% 3 9% 26% 30% 16%	2160
	11th to 20th	Day	29% 7% 13% 28% 17% 5%	2048
	21st to end	Day	28% 6% 13% 24% 20% 9%	1959
October	1st to 10th	Day	32% 7% 11% 21% 22% 8%	1800
	11th to 20th	Day	39% 6% 12% 17% 20% 6%	1800
	21st to end	Day	43% 7% 11% 17% 14% 8%	1980
November	1st to 10th	Day	59% 8% 9% 12% 10% 2	1705
	11th to 20th	Day	58% 8% 12% 10% 6% 6%	1520
	21st to end	Day	55% 5% 8% 11% 11% 9%	1520
December	1st to 10th	Day	52% 6% 9% 15% 14% 4	1520
	11th to 20th	Day	66% 7% 11% 9% 7% 1	1928
	21st to end	Day	70% 6% 6% 11% 5% 2	2794
January	1st to 10th	Night	71% 5% 7% 9% 5% 3	2646
	11th to 20th	Night	58% 5% 8% 10% 9% 11%	2429
	21st to end	Night	56% 4 8% 11% 14% 7%	2574
February	1st to 10th	Night	54% 6% 13% 14% 9% 3	2340
	11th to 20th	Night	55% 5% 11% 18% 9% 2	2274
	21st to end	Night	58% 9% 10% 12% 8% 3	1849
March	1st to 10th	Night	61% 6% 10% 15% 8% 1	1980
	11th to 20th	Night	60% 7% 11% 12% 8% 1	1980
	21st to end	Night	63% 7% 12% 12% 5% 1	2178
April	1st to 10th	Night	59% 7% 11% 16% 7% 1	1837
	11th to 20th	Night	53% 7% 14% 14% 9% 3	1757
	21st to end	Night	47% 8% 13% 22% 9% 1	1620
May	1st to 10th	Night	36% 6% 16% 29% 11% 3	1620
	11th to 20th	Night	42% 9% 16% 20% 11% 3	1480
	21st to end	Night	37% 7% 18% 32% 7%	1552
June	1st to 10th	Night	41% 7% 12% 28% 12%	1440
	11th to 20th	Night	22% 6% 15% 40% 14% 2	1440
	21st to end	Night	17% 4 12% 38% 23% 7%	1440
July	1st to 10th	Night	13% 3 8% 30% 30% 17%	1400
	11th to 20th	Night	13% 3 7% 21% 37% 20%	1435
	21st to end	Night	6% 1 4 25% 43% 21%	1674
August	1st to 10th	Night	11% 4 10% 35% 33% 8%	1602
	11th to 20th	Night	10% 3 8% 31% 36% 12%	1602
	21st to end	Night	12% 3 10% 29% 34% 12%	1885
September	1st to 10th	Night	12% 3 9% 24% 33% 19%	1800
	11th to 20th	Night	23% 6% 13% 30% 20% 7%	1908
	21st to end	Night	27% 6% 14% 20% 18% 15%	2000
October	1st to 10th	Night	28% 7% 13% 19% 22% 11%	2160
	11th to 20th	Night	38% 5% 12% 19% 18% 8%	2160
	21st to end	Night	44% 6% 9% 16% 15% 10%	2376
November	1st to 10th	Night	55% 7% 9% 13% 11% 5%	2369
	11th to 20th	Night	61% 7% 8% 12% 8% 5%	2660
	21st to end	Night	51% 7% 10% 11% 12% 9%	2660
December	1st to 10th	Night	52% 7% 8% 15% 15% 4	2660
	11th to 20th	Night	64% 5% 8% 11% 10% 2	3276
	21st to end	Night	63% 7% 8% 14% 5% 2	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	50% 12% 21% 12% 5% 1	180
	11th to 20th	Day	42% 11% 17% 15% 12% 1	356
	21st to end	Day	34% 11% 25% 17% 12% 2	374
February	1st to 10th	Day	33% 12% 27% 20% 9%	340
	11th to 20th	Day	37% 15% 25% 19% 3 1	335
	21st to end	Day	40% 17% 24% 16% 3 1	298
March	1st to 10th	Day	41% 17% 21% 17% 4	420
	11th to 20th	Day	33% 14% 25% 18% 8% 1	420
	21st to end	Day	36% 16% 26% 17% 4	462
April	1st to 10th	Day	34% 15% 25% 20% 6%	420
	11th to 20th	Day	32% 18% 24% 19% 5% 2	412
	21st to end	Day	28% 16% 27% 21% 7% 1	420
May	1st to 10th	Day	17% 18% 34% 21% 9% 1	423
	11th to 20th	Day	27% 13% 25% 23% 10% 2	448
	21st to end	Day	19% 14% 33% 26% 7% 1	485
June	1st to 10th	Day	18% 13% 30% 27% 10% 2	450
	11th to 20th	Day	16% 17% 39% 22% 6%	450
	21st to end	Day	5% 6% 37% 39% 11% 2	450
July	1st to 10th	Day	5% 5% 38% 41% 10% 1	446
	11th to 20th	Day	4 5% 40% 39% 9% 2	444
	21st to end	Day	1 2 35% 44% 15% 2	487
August	1st to 10th	Day	1 2 29% 45% 19% 3	447
	11th to 20th	Day	3 2 29% 43% 20% 3	437
	21st to end	Day	5% 3 36% 39% 15% 2	495
September	1st to 10th	Day	4 5% 30% 42% 16% 4	450
	11th to 20th	Day	12% 8% 26% 34% 19% 2	450
	21st to end	Day	14% 9% 30% 31% 14% 2	450
October	1st to 10th	Day	14% 12% 26% 28% 17% 3	450
	11th to 20th	Day	21% 9% 25% 24% 17% 4	450
	21st to end	Day	22% 16% 23% 26% 11% 3	495
November	1st to 10th	Day	30% 14% 23% 20% 10% 3	353
	11th to 20th	Day	30% 14% 19% 21% 14% 3	180
	21st to end	Day	29% 12% 21% 25% 13%	180
December	1st to 10th	Day	27% 17% 19% 23% 11% 3	180
	11th to 20th	Day	43% 9% 19% 22% 5% 2	180
	21st to end	Day	43% 11% 21% 18% 7% 1	198
January	1st to 10th	Night	42% 12% 18% 18% 9% 1	760
	11th to 20th	Night	38% 9% 16% 22% 12% 3	748
	21st to end	Night	32% 7% 18% 29% 12% 2	792
February	1st to 10th	Night	31% 9% 19% 26% 15% 1	720
	11th to 20th	Night	32% 10% 19% 27% 11% 2	704
	21st to end	Night	37% 12% 17% 26% 9%	592
March	1st to 10th	Night	34% 12% 20% 23% 9% 2	720
	11th to 20th	Night	33% 9% 19% 25% 15%	720
	21st to end	Night	38% 12% 20% 20% 9% 1	792
April	1st to 10th	Night	32% 13% 18% 22% 13% 2	720
	11th to 20th	Night	29% 11% 22% 24% 12% 2	689
	21st to end	Night	25% 7% 21% 31% 15% 1	540
May	1st to 10th	Night	18% 8% 29% 30% 13% 1	540
	11th to 20th	Night	17% 8% 18% 31% 23% 2	418
	21st to end	Night	20% 8% 23% 32% 14% 3	389
June	1st to 10th	Night	19% 5% 25% 33% 16% 1	360
	11th to 20th	Night	10% 4 39% 32% 14% 1	360
	21st to end	Night	8% 4 24% 41% 21% 2	360
July	1st to 10th	Night	5% 23% 43% 29% 1	350
	11th to 20th	Night	3 1 31% 44% 20% 1	391
	21st to end	Night	2 24% 44% 26% 4	591
August	1st to 10th	Night	1 1 15% 45% 32% 5%	537
	11th to 20th	Night	3 1 13% 45% 31% 7%	534
	21st to end	Night	5% 3 25% 39% 25% 4	697
September	1st to 10th	Night	3 3 18% 44% 28% 3	720
	11th to 20th	Night	7% 4 15% 33% 32% 9%	720
	21st to end	Night	13% 5% 20% 36% 22% 5%	720
October	1st to 10th	Night	12% 6% 23% 32% 23% 4	720
	11th to 20th	Night	19% 7% 19% 30% 21% 5%	720
	21st to end	Night	23% 10% 19% 30% 14% 5%	792
November	1st to 10th	Night	30% 8% 20% 27% 13% 2	740
	11th to 20th	Night	33% 10% 19% 27% 10% 1	760
	21st to end	Night	27% 11% 21% 29% 12% 1	760
December	1st to 10th	Night	30% 9% 20% 27% 11% 2	760
	11th to 20th	Night	41% 8% 18% 22% 9% 1	760
	21st to end	Night	46% 9% 19% 19% 6%	836

Page generated at 2024-01-14 06:55:05. Version ac07

Copyright 2024 Attilla Danko