Wheatland
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wheatland clear sky chart from 2005-11-06 to 2024-03-01.

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% 5% 2 4 4 3 4 5% 6% 8% 52%	78487
	Night	6% 6% 2 4 4 3 4 4 5% 7% 54%	80985
Transparency	Day	30% 4 12% 27% 20% 8%	78190
	Night	30% 3 13% 28% 19% 6%	80804
Seeing	Day	11% 10% 28% 29% 17% 5%	14731
	Night	10% 11% 33% 35% 11% 1	24936

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	3 8% 3 7% 5% 3 4 3 4 6% 52%	2538
	11th to 20th	Day	4 9% 3 6% 6% 4 5% 5% 6% 8% 43%	2540
	21st to end	Day	3 6% 2 4 4 2 3 3 4 7% 62%	3050
February	1st to 10th	Day	4 9% 5% 7% 5% 3 4 4 6% 8% 45%	1710
	11th to 20th	Day	3 8% 4 7% 5% 4 5% 4 5% 7% 47%	1778
	21st to end	Day	4 7% 3 7% 5% 2 4 3 5% 7% 53%	1570
March	1st to 10th	Day	5% 7% 3 6% 4 3 5% 5% 5% 7% 51%	1800
	11th to 20th	Day	6% 5% 2 4 5% 2 4 6% 6% 7% 51%	1930
	21st to end	Day	9% 7% 3 5% 6% 4 4 4 5% 8% 45%	2322
April	1st to 10th	Day	9% 8% 3 5% 4 3 4 4 5% 8% 48%	2160
	11th to 20th	Day	13% 8% 3 6% 5% 3 6% 6% 6% 7% 37%	2131
	21st to end	Day	11% 7% 2 5% 5% 3 5% 6% 5% 8% 43%	2165
May	1st to 10th	Day	14% 6% 2 5% 5% 4 5% 5% 6% 9% 41%	2416
	11th to 20th	Day	16% 6% 2 4 6% 3 5% 5% 6% 9% 38%	2478
	21st to end	Day	10% 4 3 4 5% 3 6% 7% 8% 9% 41%	2724
June	1st to 10th	Day	5% 3 1 3 4 3 4 7% 8% 12% 50%	2520
	11th to 20th	Day	8% 3 1 3 4 3 5% 5% 6% 9% 53%	2520
	21st to end	Day	4 2 1 3 4 2 5% 6% 7% 9% 57%	2520
July	1st to 10th	Day	4 3 1 3 5% 3 5% 7% 8% 10% 51%	2520
	11th to 20th	Day	3 2 1 3 4 2 5% 5% 7% 10% 57%	2520
	21st to end	Day	5% 3 2 4 4 3 5% 5% 8% 10% 51%	2742
August	1st to 10th	Day	3 3 1 3 4 4 6% 7% 7% 10% 53%	2396
	11th to 20th	Day	4 2 1 3 4 2 5% 5% 7% 9% 58%	2176
	21st to end	Day	3 3 2 3 4 3 4 5% 6% 7% 60%	2376
September	1st to 10th	Day	6% 3 1 3 4 2 4 3 5% 6% 63%	2160
	11th to 20th	Day	7% 3 1 3 3 2 3 3 4 7% 64%	2139
	21st to end	Day	6% 3 2 3 3 2 3 4 4 7% 63%	1980
October	1st to 10th	Day	8% 5% 2 4 3 3 3 3 4 6% 57%	1809
	11th to 20th	Day	8% 4 2 3 4 2 3 5% 4 5% 59%	1800
	21st to end	Day	6% 6% 2 4 3 1 3 4 5% 8% 58%	1858
November	1st to 10th	Day	4 5% 3 4 5% 3 3 5% 5% 9% 56%	1673
	11th to 20th	Day	4 5% 3 3 3 2 3 3 5% 8% 60%	1706
	21st to end	Day	3 7% 3 5% 3 2 3 4 6% 7% 55%	1520
December	1st to 10th	Day	3 8% 3 5% 4 3 5% 5% 5% 9% 50%	1520
	11th to 20th	Day	4 6% 3 5% 4 2 3 4 5% 9% 56%	1926
	21st to end	Day	7% 9% 3 5% 5% 2 4 3 5% 7% 50%	2794
January	1st to 10th	Night	3 8% 4 6% 5% 3 3 4 5% 7% 51%	4417
	11th to 20th	Night	2 8% 4 6% 6% 4 4 4 5% 8% 49%	4430
	21st to end	Night	3 7% 2 5% 4 2 4 4 4 6% 58%	4646
February	1st to 10th	Night	4 8% 4 7% 5% 3 5% 5% 5% 8% 46%	2470
	11th to 20th	Night	4 10% 4 6% 5% 3 4 4 6% 6% 47%	2287
	21st to end	Night	3 8% 3 6% 5% 3 4 5% 5% 7% 52%	1884
March	1st to 10th	Night	5% 9% 3 4 3 3 4 4 4 8% 52%	2166
	11th to 20th	Night	7% 7% 3 4 4 3 3 4 5% 7% 52%	2026
	21st to end	Night	9% 9% 3 6% 5% 3 4 4 6% 6% 45%	2034
April	1st to 10th	Night	11% 7% 3 4 4 2 4 5% 5% 6% 49%	1800
	11th to 20th	Night	12% 6% 2 5% 5% 3 5% 5% 4 7% 45%	1777
	21st to end	Night	14% 8% 2 6% 4 2 4 4 4 7% 45%	1792
May	1st to 10th	Night	16% 6% 2 5% 3 3 4 5% 5% 6% 45%	1541
	11th to 20th	Night	16% 5% 1 4 4 2 3 4 5% 7% 48%	1417
	21st to end	Night	10% 4 1 3 5% 3 6% 6% 7% 9% 46%	1552
June	1st to 10th	Night	5% 4 1 3 4 3 3 5% 7% 10% 55%	1440
	11th to 20th	Night	8% 2 2 3 3 2 4 5% 6% 9% 56%	1440
	21st to end	Night	3 2 1 3 3 2 4 4 4 9% 64%	1440
July	1st to 10th	Night	6% 2 1 3 3 2 5% 5% 7% 9% 56%	1440
	11th to 20th	Night	4 2 1 2 3 3 4 5% 5% 7% 63%	1440
	21st to end	Night	4 2 1 3 4 3 5% 5% 7% 9% 56%	1576
August	1st to 10th	Night	4 3 1 3 4 3 6% 5% 7% 11% 53%	1540
	11th to 20th	Night	3 3 1 4 4 2 4 4 6% 8% 62%	1723
	21st to end	Night	3 3 1 4 4 3 4 4 5% 7% 61%	1980
September	1st to 10th	Night	7% 4 1 3 3 2 3 3 4 6% 64%	1800
	11th to 20th	Night	7% 3 1 3 3 3 2 3 4 6% 64%	1820
	21st to end	Night	8% 3 1 3 3 2 3 3 4 6% 65%	1980
October	1st to 10th	Night	10% 5% 1 3 3 2 4 4 5% 6% 57%	2149
	11th to 20th	Night	8% 6% 2 3 4 2 3 3 4 5% 61%	2160
	21st to end	Night	8% 7% 2 4 4 2 3 3 5% 5% 57%	2479
November	1st to 10th	Night	6% 5% 2 4 4 2 3 3 5% 8% 57%	2405
	11th to 20th	Night	4 6% 2 4 4 3 5% 4 6% 7% 53%	2470
	21st to end	Night	5% 8% 3 4 4 2 4 4 4 7% 56%	2660
December	1st to 10th	Night	4 8% 3 5% 5% 3 4 4 5% 7% 52%	2660
	11th to 20th	Night	4 7% 2 4 4 3 3 3 5% 7% 57%	3271
	21st to end	Night	8% 10% 3 5% 5% 3 3 4 5% 7% 47%	4873

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	35% 2 13% 30% 20% 1	2539
	11th to 20th	Day	40% 3 19% 22% 14% 2	2540
	21st to end	Day	24% 2 19% 35% 16% 4	3050
February	1st to 10th	Day	38% 3 16% 27% 14% 2	1710
	11th to 20th	Day	36% 4 10% 29% 16% 5%	1787
	21st to end	Day	31% 3 16% 26% 18% 5%	1570
March	1st to 10th	Day	33% 3 11% 30% 20% 3	1800
	11th to 20th	Day	30% 4 13% 29% 20% 4	1930
	21st to end	Day	38% 5% 12% 28% 15% 2	2322
April	1st to 10th	Day	34% 5% 15% 24% 17% 5%	2160
	11th to 20th	Day	44% 5% 9% 22% 16% 4	2134
	21st to end	Day	39% 4 10% 27% 18% 2	2165
May	1st to 10th	Day	40% 4 13% 28% 13% 2	2416
	11th to 20th	Day	42% 5% 14% 25% 11% 2	2482
	21st to end	Day	36% 5% 18% 25% 14% 3	2724
June	1st to 10th	Day	26% 5% 16% 29% 18% 6%	2520
	11th to 20th	Day	28% 4 11% 23% 20% 14%	2520
	21st to end	Day	22% 4 8% 25% 26% 15%	2520
July	1st to 10th	Day	25% 6% 9% 23% 26% 12%	2451
	11th to 20th	Day	20% 4 8% 24% 24% 20%	2445
	21st to end	Day	27% 4 10% 25% 21% 13%	2590
August	1st to 10th	Day	23% 4 12% 28% 19% 13%	2380
	11th to 20th	Day	22% 4 8% 27% 24% 15%	2176
	21st to end	Day	21% 4 6% 20% 31% 18%	2376
September	1st to 10th	Day	22% 3 5% 19% 29% 22%	2160
	11th to 20th	Day	21% 2 6% 24% 29% 18%	2139
	21st to end	Day	22% 3 6% 28% 33% 9%	1980
October	1st to 10th	Day	30% 3 9% 28% 23% 8%	1809
	11th to 20th	Day	28% 2 9% 28% 23% 9%	1800
	21st to end	Day	26% 3 12% 31% 23% 6%	1858
November	1st to 10th	Day	27% 2 12% 27% 25% 7%	1673
	11th to 20th	Day	24% 2 12% 34% 23% 5%	1706
	21st to end	Day	28% 3 11% 29% 25% 4	1520
December	1st to 10th	Day	31% 4 16% 28% 18% 3	1520
	11th to 20th	Day	27% 2 12% 39% 18% 1	1924
	21st to end	Day	36% 2 11% 33% 15% 3	2794
January	1st to 10th	Night	34% 2 11% 35% 15% 2	4417
	11th to 20th	Night	36% 5% 18% 20% 17% 4	4430
	21st to end	Night	29% 2 22% 33% 12% 2	4646
February	1st to 10th	Night	36% 4 16% 28% 14% 2	2470
	11th to 20th	Night	37% 4 12% 28% 16% 4	2288
	21st to end	Night	32% 3 12% 28% 22% 3	1884
March	1st to 10th	Night	32% 2 11% 31% 20% 3	2166
	11th to 20th	Night	32% 3 11% 28% 22% 4	2026
	21st to end	Night	39% 3 13% 28% 16% 2	2034
April	1st to 10th	Night	35% 5% 12% 26% 16% 5%	1800
	11th to 20th	Night	39% 4 11% 25% 16% 4	1777
	21st to end	Night	40% 2 9% 27% 20% 2	1792
May	1st to 10th	Night	40% 3 13% 28% 15% 2	1541
	11th to 20th	Night	35% 5% 17% 28% 13% 2	1418
	21st to end	Night	33% 6% 17% 26% 15% 3	1552
June	1st to 10th	Night	24% 4 23% 27% 17% 6%	1440
	11th to 20th	Night	24% 3 13% 26% 22% 11%	1440
	21st to end	Night	19% 4 11% 28% 25% 13%	1440
July	1st to 10th	Night	23% 4 12% 28% 21% 12%	1400
	11th to 20th	Night	20% 4 9% 24% 25% 19%	1392
	21st to end	Night	23% 4 14% 26% 23% 10%	1488
August	1st to 10th	Night	23% 4 17% 27% 17% 11%	1532
	11th to 20th	Night	21% 3 10% 27% 24% 16%	1723
	21st to end	Night	23% 3 7% 21% 28% 18%	1980
September	1st to 10th	Night	23% 2 5% 22% 28% 19%	1800
	11th to 20th	Night	23% 2 7% 26% 25% 17%	1820
	21st to end	Night	22% 3 6% 28% 28% 14%	1980
October	1st to 10th	Night	28% 3 11% 24% 25% 8%	2149
	11th to 20th	Night	28% 2 10% 27% 22% 11%	2160
	21st to end	Night	29% 2 11% 29% 20% 9%	2479
November	1st to 10th	Night	27% 3 13% 26% 26% 6%	2405
	11th to 20th	Night	29% 3 10% 31% 21% 6%	2470
	21st to end	Night	29% 3 10% 31% 23% 6%	2660
December	1st to 10th	Night	33% 3 15% 28% 19% 4	2660
	11th to 20th	Night	28% 3 13% 38% 17% 1	3272
	21st to end	Night	38% 3 10% 32% 15% 3	4873

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	13% 16% 33% 27% 8% 3	270
	11th to 20th	Day	15% 21% 35% 23% 5% 1	270
	21st to end	Day	7% 22% 46% 17% 7%	297
February	1st to 10th	Day	9% 25% 44% 18% 3 1	270
	11th to 20th	Day	15% 27% 30% 24% 4	270
	21st to end	Day	18% 24% 31% 21% 5%	225
March	1st to 10th	Day	8% 23% 33% 33% 4	240
	11th to 20th	Day	16% 15% 35% 24% 9% 1	370
	21st to end	Day	19% 16% 34% 23% 6% 2	462
April	1st to 10th	Day	18% 18% 37% 21% 6%	420
	11th to 20th	Day	22% 17% 36% 17% 6% 2	412
	21st to end	Day	18% 11% 32% 24% 12% 3	425
May	1st to 10th	Day	17% 10% 29% 26% 15% 3	603
	11th to 20th	Day	22% 6% 18% 29% 20% 4	625
	21st to end	Day	13% 8% 22% 33% 18% 6%	679
June	1st to 10th	Day	5% 6% 23% 30% 26% 11%	630
	11th to 20th	Day	10% 7% 26% 35% 18% 3	630
	21st to end	Day	6% 2 26% 35% 26% 5%	630
July	1st to 10th	Day	6% 1 15% 38% 30% 10%	621
	11th to 20th	Day	4 3 19% 35% 33% 6%	618
	21st to end	Day	6% 2 15% 35% 34% 7%	684
August	1st to 10th	Day	5% 3 21% 35% 28% 8%	515
	11th to 20th	Day	4 3 22% 32% 27% 13%	437
	21st to end	Day	4 5% 23% 33% 23% 11%	495
September	1st to 10th	Day	7% 6% 24% 34% 22% 8%	450
	11th to 20th	Day	7% 5% 24% 33% 23% 7%	429
	21st to end	Day	9% 7% 22% 34% 16% 13%	270
October	1st to 10th	Day	11% 8% 20% 30% 18% 12%	270
	11th to 20th	Day	12% 14% 27% 28% 13% 6%	270
	21st to end	Day	13% 14% 33% 27% 10% 3	297
November	1st to 10th	Day	10% 10% 35% 33% 10% 3	270
	11th to 20th	Day	14% 17% 35% 26% 8% 1	270
	21st to end	Day	10% 16% 40% 26% 7%	270
December	1st to 10th	Day	10% 20% 43% 19% 8%	270
	11th to 20th	Day	9% 21% 48% 19% 2	270
	21st to end	Day	14% 23% 35% 22% 5% 1	297
January	1st to 10th	Night	10% 20% 40% 22% 7% 1	950
	11th to 20th	Night	9% 24% 44% 20% 4	950
	21st to end	Night	10% 17% 45% 24% 4	909
February	1st to 10th	Night	9% 17% 46% 24% 4	760
	11th to 20th	Night	12% 15% 40% 28% 5%	744
	21st to end	Night	11% 19% 41% 25% 4	628
March	1st to 10th	Night	10% 16% 39% 30% 4	722
	11th to 20th	Night	13% 11% 32% 37% 8%	720
	21st to end	Night	15% 11% 36% 32% 6% 1	648
April	1st to 10th	Night	14% 12% 36% 33% 4	540
	11th to 20th	Night	15% 9% 36% 32% 8%	533
	21st to end	Night	17% 7% 29% 35% 11% 1	540
May	1st to 10th	Night	19% 7% 24% 34% 14% 1	540
	11th to 20th	Night	18% 4 19% 40% 18% 2	531
	21st to end	Night	10% 4 28% 41% 17%	584
June	1st to 10th	Night	7% 4 25% 42% 21% 1	540
	11th to 20th	Night	10% 3 29% 48% 9% 1	540
	21st to end	Night	4 2 29% 49% 17% 1	540
July	1st to 10th	Night	7% 2 12% 50% 28% 1	525
	11th to 20th	Night	4 2 19% 52% 22% 1	522
	21st to end	Night	4 1 13% 53% 27% 1	591
August	1st to 10th	Night	7% 1 11% 54% 25% 1	537
	11th to 20th	Night	3 1 18% 54% 23% 1	534
	21st to end	Night	4 2 17% 50% 26% 1	594
September	1st to 10th	Night	9% 2 19% 47% 20% 2	540
	11th to 20th	Night	9% 4 21% 45% 19% 2	540
	21st to end	Night	10% 3 26% 45% 16% 1	540
October	1st to 10th	Night	14% 5% 27% 36% 17% 2	709
	11th to 20th	Night	12% 7% 32% 39% 10% 1	720
	21st to end	Night	13% 9% 34% 35% 8% 1	895
November	1st to 10th	Night	11% 7% 40% 34% 7% 1	925
	11th to 20th	Night	8% 17% 43% 28% 4	950
	21st to end	Night	9% 12% 41% 32% 6%	950
December	1st to 10th	Night	11% 22% 41% 23% 4	950
	11th to 20th	Night	10% 18% 44% 23% 4	950
	21st to end	Night	13% 21% 41% 21% 4	1045

Page generated at 2024-02-27 04:30:15. Version ac07

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