Tulsa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tulsa clear sky chart from 2005-11-06 to 2024-03-28.

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	11% 6% 3 5% 5% 3 4 4 5% 7% 48%	79225
	Night	11% 5% 2 4 4 2 3 4 4 7% 53%	80830
Transparency	Day	36% 5% 10% 25% 20% 4	78950
	Night	32% 4 10% 24% 23% 6%	80625
Seeing	Day	14% 10% 26% 28% 18% 4	14517
	Night	13% 9% 31% 32% 13% 1	24581

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	10% 10% 5% 5% 4 3 4 3 4 5% 46%	2847
	11th to 20th	Day	9% 6% 2 6% 4 2 3 4 5% 6% 53%	2850
	21st to end	Day	21% 11% 3 4 3 2 2 2 3 4 45%	3135
February	1st to 10th	Day	14% 10% 4 6% 5% 3 4 3 4 5% 43%	1710
	11th to 20th	Day	14% 6% 4 5% 5% 2 4 4 5% 7% 46%	1800
	21st to end	Day	14% 8% 3 4 5% 3 4 4 4 6% 45%	1604
March	1st to 10th	Day	13% 8% 3 4 4 2 3 3 4 6% 50%	2090
	11th to 20th	Day	18% 7% 3 5% 3 3 3 4 5% 6% 44%	2090
	21st to end	Day	16% 10% 4 7% 5% 2 4 4 5% 6% 38%	2255
April	1st to 10th	Day	10% 6% 2 5% 4 4 4 5% 7% 7% 47%	1984
	11th to 20th	Day	15% 6% 3 5% 4 3 5% 4 5% 7% 44%	2134
	21st to end	Day	18% 7% 3 6% 4 2 4 3 5% 6% 41%	2309
May	1st to 10th	Day	18% 6% 3 5% 6% 3 4 4 5% 6% 41%	2340
	11th to 20th	Day	13% 7% 2 5% 6% 3 5% 5% 6% 7% 41%	2302
	21st to end	Day	13% 6% 3 5% 6% 4 6% 6% 6% 10% 36%	2531
June	1st to 10th	Day	6% 4 2 5% 6% 3 6% 6% 7% 9% 48%	2340
	11th to 20th	Day	8% 3 2 5% 5% 4 5% 5% 6% 7% 49%	2340
	21st to end	Day	6% 2 1 3 3 2 5% 5% 6% 8% 57%	2340
July	1st to 10th	Day	8% 3 2 4 5% 3 6% 7% 8% 10% 43%	2340
	11th to 20th	Day	4 3 1 4 4 3 5% 5% 6% 9% 56%	2340
	21st to end	Day	7% 4 2 4 5% 4 5% 5% 5% 10% 49%	2546
August	1st to 10th	Day	5% 3 2 4 5% 3 5% 6% 8% 11% 50%	2328
	11th to 20th	Day	8% 5% 2 5% 5% 3 4 6% 7% 9% 46%	2301
	21st to end	Day	4 3 2 4 4 3 5% 5% 6% 10% 53%	2449
September	1st to 10th	Day	10% 5% 2 4 5% 2 4 4 4 6% 53%	2022
	11th to 20th	Day	12% 4 2 5% 4 3 4 5% 6% 8% 47%	1980
	21st to end	Day	8% 3 2 4 4 3 4 4 4 6% 57%	1980
October	1st to 10th	Day	9% 4 2 3 4 2 4 4 4 8% 56%	1864
	11th to 20th	Day	11% 4 2 3 2 2 2 3 4 5% 62%	1800
	21st to end	Day	15% 6% 2 4 3 2 3 3 3 5% 54%	1980
November	1st to 10th	Day	9% 4 2 3 3 2 3 3 5% 6% 58%	1858
	11th to 20th	Day	10% 5% 2 3 3 2 3 2 3 6% 61%	1720
	21st to end	Day	14% 7% 2 4 3 2 2 3 5% 5% 53%	1710
December	1st to 10th	Day	12% 6% 2 5% 4 2 4 4 5% 5% 50%	1710
	11th to 20th	Day	14% 8% 3 6% 5% 3 3 3 3 6% 46%	2161
	21st to end	Day	16% 10% 5% 8% 7% 3 4 4 5% 5% 33%	3135
January	1st to 10th	Night	11% 8% 4 5% 5% 2 4 4 5% 5% 48%	4108
	11th to 20th	Night	8% 5% 2 4 4 3 4 4 5% 6% 55%	4120
	21st to end	Night	22% 8% 3 3 3 2 2 3 3 5% 47%	4532
February	1st to 10th	Night	14% 9% 3 6% 4 2 3 3 4 6% 47%	2470
	11th to 20th	Night	14% 7% 3 5% 3 2 3 3 3 7% 50%	2284
	21st to end	Night	13% 7% 3 4 4 3 4 4 4 4 50%	1848
March	1st to 10th	Night	11% 6% 3 5% 5% 3 4 4 4 5% 50%	2090
	11th to 20th	Night	16% 5% 2 4 4 2 3 3 4 6% 51%	2090
	21st to end	Night	16% 6% 2 5% 5% 2 3 3 4 6% 46%	2255
April	1st to 10th	Night	12% 4 2 3 4 2 3 4 5% 7% 54%	1974
	11th to 20th	Night	14% 6% 1 4 4 2 4 4 3 7% 50%	1775
	21st to end	Night	14% 7% 3 4 4 2 3 3 4 5% 50%	1648
May	1st to 10th	Night	13% 5% 3 4 5% 3 5% 4 5% 7% 47%	1620
	11th to 20th	Night	13% 6% 2 4 4 3 4 4 6% 8% 47%	1593
	21st to end	Night	9% 5% 2 5% 4 3 4 5% 7% 12% 45%	1745
June	1st to 10th	Night	5% 4 1 3 4 3 4 5% 6% 9% 56%	1620
	11th to 20th	Night	6% 2 2 3 4 2 3 4 7% 11% 56%	1620
	21st to end	Night	3 1 1 2 3 2 4 3 5% 9% 65%	1620
July	1st to 10th	Night	4 3 2 5% 4 2 5% 5% 6% 11% 52%	1620
	11th to 20th	Night	3 2 1 3 4 2 5% 4 6% 8% 63%	1620
	21st to end	Night	5% 3 2 3 4 2 4 5% 6% 8% 57%	1772
August	1st to 10th	Night	3 2 1 3 3 3 5% 5% 7% 11% 56%	1611
	11th to 20th	Night	5% 3 2 5% 5% 2 6% 6% 6% 7% 54%	1600
	21st to end	Night	3 2 1 4 3 3 4 5% 6% 10% 60%	1905
September	1st to 10th	Night	9% 3 2 4 4 2 3 4 4 6% 59%	1934
	11th to 20th	Night	11% 4 2 4 4 3 4 4 5% 7% 51%	1980
	21st to end	Night	7% 4 2 3 4 2 3 4 4 6% 60%	1980
October	1st to 10th	Night	8% 3 2 3 4 2 3 4 5% 6% 60%	2077
	11th to 20th	Night	12% 5% 2 3 3 2 3 3 3 5% 60%	2160
	21st to end	Night	14% 6% 2 4 3 2 2 2 3 4 58%	2376
November	1st to 10th	Night	10% 5% 2 3 2 1 2 3 3 5% 64%	2220
	11th to 20th	Night	9% 5% 2 4 4 2 3 3 4 6% 59%	2455
	21st to end	Night	14% 6% 2 3 4 2 3 3 4 5% 55%	2470
December	1st to 10th	Night	13% 6% 3 3 4 3 3 4 4 6% 52%	2470
	11th to 20th	Night	13% 7% 3 5% 4 3 4 3 3 5% 50%	3036
	21st to end	Night	17% 9% 3 5% 4 3 3 3 4 5% 43%	4532

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	41% 4 9% 24% 21% 2	2848
	11th to 20th	Day	32% 3 15% 27% 19% 5%	2850
	21st to end	Day	46% 2 7% 21% 22% 2	3135
February	1st to 10th	Day	45% 4 11% 21% 16% 4	1710
	11th to 20th	Day	39% 5% 8% 26% 18% 4	1810
	21st to end	Day	42% 3 7% 21% 19% 8%	1604
March	1st to 10th	Day	38% 3 6% 24% 19% 10%	2090
	11th to 20th	Day	42% 5% 9% 22% 16% 5%	2090
	21st to end	Day	47% 5% 11% 21% 13% 3	2255
April	1st to 10th	Day	36% 6% 10% 24% 18% 5%	1984
	11th to 20th	Day	40% 5% 10% 23% 15% 6%	2134
	21st to end	Day	44% 5% 8% 23% 17% 2	2309
May	1st to 10th	Day	44% 6% 8% 21% 19% 2	2340
	11th to 20th	Day	42% 7% 12% 24% 14% 1	2306
	21st to end	Day	43% 8% 14% 23% 11% 1	2531
June	1st to 10th	Day	31% 8% 13% 28% 17% 3	2340
	11th to 20th	Day	33% 7% 13% 28% 16% 3	2340
	21st to end	Day	24% 6% 13% 30% 22% 5%	2340
July	1st to 10th	Day	31% 9% 15% 27% 17% 1	2276
	11th to 20th	Day	23% 7% 13% 30% 25% 3	2271
	21st to end	Day	29% 7% 14% 32% 17%	2405
August	1st to 10th	Day	26% 7% 16% 28% 18% 4	2314
	11th to 20th	Day	32% 8% 13% 24% 21% 2	2301
	21st to end	Day	25% 7% 13% 29% 19% 6%	2449
September	1st to 10th	Day	32% 5% 9% 23% 23% 8%	2022
	11th to 20th	Day	34% 8% 11% 20% 22% 6%	1980
	21st to end	Day	28% 5% 8% 24% 29% 7%	1980
October	1st to 10th	Day	27% 5% 11% 24% 26% 6%	1864
	11th to 20th	Day	27% 3 7% 23% 32% 9%	1800
	21st to end	Day	35% 3 7% 26% 20% 8%	1980
November	1st to 10th	Day	28% 3 7% 27% 27% 8%	1858
	11th to 20th	Day	28% 3 8% 28% 26% 7%	1720
	21st to end	Day	34% 3 8% 24% 25% 6%	1710
December	1st to 10th	Day	35% 5% 8% 28% 22% 2	1710
	11th to 20th	Day	41% 3 6% 22% 24% 4	2159
	21st to end	Day	52% 4 10% 20% 12% 3	3135
January	1st to 10th	Night	37% 4 9% 25% 21% 4	4108
	11th to 20th	Night	29% 5% 17% 22% 24% 3	4120
	21st to end	Night	42% 3 9% 21% 22% 4	4532
February	1st to 10th	Night	41% 3 11% 22% 19% 5%	2470
	11th to 20th	Night	38% 3 7% 27% 20% 6%	2284
	21st to end	Night	37% 4 8% 19% 23% 10%	1848
March	1st to 10th	Night	37% 4 8% 18% 21% 11%	2090
	11th to 20th	Night	36% 4 10% 23% 20% 7%	2090
	21st to end	Night	39% 5% 11% 26% 17% 3	2255
April	1st to 10th	Night	31% 5% 10% 23% 23% 9%	1974
	11th to 20th	Night	35% 5% 10% 24% 18% 9%	1775
	21st to end	Night	38% 4 9% 24% 23% 3	1648
May	1st to 10th	Night	36% 6% 12% 22% 21% 4	1620
	11th to 20th	Night	35% 6% 13% 26% 18% 3	1594
	21st to end	Night	32% 8% 17% 28% 13% 2	1746
June	1st to 10th	Night	24% 8% 16% 30% 19% 3	1620
	11th to 20th	Night	22% 6% 15% 33% 20% 4	1620
	21st to end	Night	18% 5% 13% 31% 26% 7%	1620
July	1st to 10th	Night	25% 8% 14% 30% 20% 3	1575
	11th to 20th	Night	18% 6% 12% 30% 28% 5%	1566
	21st to end	Night	23% 6% 11% 34% 24% 2	1673
August	1st to 10th	Night	20% 7% 14% 35% 21% 3	1601
	11th to 20th	Night	27% 8% 11% 20% 27% 7%	1600
	21st to end	Night	20% 6% 12% 31% 22% 9%	1905
September	1st to 10th	Night	27% 4 9% 26% 25% 10%	1934
	11th to 20th	Night	32% 6% 10% 19% 26% 7%	1980
	21st to end	Night	24% 5% 8% 24% 31% 8%	1980
October	1st to 10th	Night	25% 4 10% 25% 26% 10%	2077
	11th to 20th	Night	28% 2 7% 20% 31% 12%	2160
	21st to end	Night	32% 3 7% 23% 26% 10%	2376
November	1st to 10th	Night	25% 3 8% 24% 30% 9%	2220
	11th to 20th	Night	28% 4 7% 25% 27% 9%	2455
	21st to end	Night	33% 3 7% 21% 29% 7%	2470
December	1st to 10th	Night	34% 4 11% 25% 21% 5%	2470
	11th to 20th	Night	38% 4 7% 21% 26% 5%	3037
	21st to end	Night	43% 3 10% 22% 18% 4	4532

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	20% 14% 35% 26% 5%	270
	11th to 20th	Day	23% 19% 40% 15% 4	270
	21st to end	Day	17% 19% 36% 19% 8%	297
February	1st to 10th	Day	24% 16% 38% 18% 3	270
	11th to 20th	Day	21% 21% 40% 16% 2	270
	21st to end	Day	31% 20% 32% 14% 2	225
March	1st to 10th	Day	19% 23% 35% 20% 3	270
	11th to 20th	Day	18% 24% 38% 17% 3	270
	21st to end	Day	21% 26% 33% 16% 3	285
April	1st to 10th	Day	14% 28% 34% 19% 5% 1	244
	11th to 20th	Day	21% 18% 35% 20% 5%	412
	21st to end	Day	21% 20% 32% 17% 8% 2	569
May	1st to 10th	Day	16% 17% 37% 24% 6% 1	603
	11th to 20th	Day	19% 9% 32% 26% 11% 3	625
	21st to end	Day	16% 8% 32% 24% 14% 7%	679
June	1st to 10th	Day	7% 5% 22% 38% 23% 5%	630
	11th to 20th	Day	10% 2 24% 39% 21% 4	630
	21st to end	Day	4 3 23% 41% 24% 5%	630
July	1st to 10th	Day	8% 2 14% 31% 32% 14%	621
	11th to 20th	Day	4 1 14% 38% 35% 7%	618
	21st to end	Day	8% 1 10% 33% 37% 12%	684
August	1st to 10th	Day	6% 2 12% 44% 30% 6%	626
	11th to 20th	Day	9% 2 16% 34% 33% 6%	615
	21st to end	Day	7% 2 7% 35% 38% 11%	568
September	1st to 10th	Day	8% 1 13% 33% 30% 15%	312
	11th to 20th	Day	7% 3 14% 38% 31% 7%	270
	21st to end	Day	12% 5% 20% 35% 23% 6%	270
October	1st to 10th	Day	10% 6% 31% 27% 20% 5%	270
	11th to 20th	Day	10% 12% 40% 27% 9% 1	270
	21st to end	Day	25% 13% 29% 23% 8% 2	297
November	1st to 10th	Day	13% 10% 39% 25% 11% 2	270
	11th to 20th	Day	15% 14% 36% 23% 10% 2	270
	21st to end	Day	24% 13% 38% 16% 8% 1	270
December	1st to 10th	Day	14% 17% 39% 19% 10% 1	270
	11th to 20th	Day	22% 15% 35% 21% 7%	270
	21st to end	Day	18% 22% 37% 20% 3	297
January	1st to 10th	Night	15% 13% 38% 29% 6%	950
	11th to 20th	Night	16% 15% 37% 26% 5%	950
	21st to end	Night	15% 14% 37% 29% 5%	1045
February	1st to 10th	Night	20% 14% 36% 26% 4	950
	11th to 20th	Night	18% 16% 35% 27% 3	809
	21st to end	Night	19% 16% 37% 25% 3	592
March	1st to 10th	Night	16% 13% 37% 30% 4	570
	11th to 20th	Night	19% 12% 38% 27% 4	570
	21st to end	Night	19% 13% 40% 23% 5%	615
April	1st to 10th	Night	14% 15% 41% 26% 4	540
	11th to 20th	Night	17% 13% 36% 28% 6%	533
	21st to end	Night	18% 12% 40% 22% 7% 1	540
May	1st to 10th	Night	15% 9% 41% 29% 6%	540
	11th to 20th	Night	14% 7% 32% 33% 14%	531
	21st to end	Night	11% 5% 31% 34% 18% 2	584
June	1st to 10th	Night	7% 3 22% 41% 26% 1	540
	11th to 20th	Night	5% 2 30% 42% 20% 1	540
	21st to end	Night	3 2 26% 49% 19% 2	540
July	1st to 10th	Night	6% 1 15% 43% 31% 3	525
	11th to 20th	Night	3 2 13% 47% 31% 4	522
	21st to end	Night	5% 1 13% 42% 37% 2	591
August	1st to 10th	Night	3 1 15% 50% 29% 2	537
	11th to 20th	Night	6% 1 13% 44% 32% 3	534
	21st to end	Night	4 1 14% 39% 39% 4	594
September	1st to 10th	Night	10% 2 13% 43% 31% 1	540
	11th to 20th	Night	13% 2 18% 40% 23% 4	540
	21st to end	Night	9% 3 21% 39% 24% 4	540
October	1st to 10th	Night	8% 3 30% 35% 21% 3	637
	11th to 20th	Night	14% 9% 36% 30% 10% 1	720
	21st to end	Night	17% 12% 30% 29% 11% 1	792
November	1st to 10th	Night	12% 8% 40% 27% 12%	740
	11th to 20th	Night	12% 14% 35% 30% 9%	935
	21st to end	Night	17% 13% 33% 27% 9%	950
December	1st to 10th	Night	16% 14% 32% 30% 7% 1	950
	11th to 20th	Night	19% 11% 35% 29% 6%	950
	21st to end	Night	18% 15% 35% 26% 6%	1045

Page generated at 2024-03-24 22:37:00. Version ac07

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