BUG: Implement interpolating NaT values in datetime series
State: closed

- [ ] closes #11701
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry


Labels:
name: Bug
name: Datetime
description: Datetime data dtype
name: Missing-data
description: np.nan, pd.NaT, pd.NA, dropna, isnull, interpolate

Comments:
Hello @scls19fr! Thanks for updating the PR.



 - In the file [`pandas/tests/series/test_missing.py`](https://github.com/pandas-dev/pandas/blob/3a90ea70cf6f1708c69c6f9c731a5a1815455f25/pandas/tests/series/test_missing.py), following are the PEP8 issues :

> [Line 1225:80](https://github.com/pandas-dev/pandas/blob/3a90ea70cf6f1708c69c6f9c731a5a1815455f25/pandas/tests/series/test_missing.py#L1225): [E501](https://duckduckgo.com/?q=pep8%20E501) line too long (82 > 79 characters)



##### Comment last updated on September 28, 2017 at 19:41 Hours UTC
If I change test from 

        expected = pd.Series(pd.date_range('2015-01-01', '2015-01-30'))

to

        expected = pd.Series(pd.date_range('2015-01-01', '2015-01-30', tz="UTC"))

unit test doesn't pass

this is because of

    if is_datetime64_dtype(self) and self.isnull().any():
        ...

Any idea?
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=h1) Report
> Merging [#17709](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/074b4850151cd2785f670e1d18c412e46c509f60?src=pr&el=desc) will **increase** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17709/graphs/tree.svg?width=650&height=150&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17709      +/-   ##
==========================================
+ Coverage   91.24%   91.26%   +0.01%     
==========================================
  Files         163      163              
  Lines       49766    49773       +7     
==========================================
+ Hits        45411    45423      +12     
+ Misses       4355     4350       -5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.05% <100%> (+0.02%)` | :arrow_up: |
| #single | `40.33% <37.5%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `95.06% <100%> (+0.12%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.73% <0%> (-0.1%)` | :arrow_down: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `92.13% <0%> (+0.05%)` | :arrow_up: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.2% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=footer). Last update [074b485...3a90ea7](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=h1) Report
> Merging [#17709](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/074b4850151cd2785f670e1d18c412e46c509f60?src=pr&el=desc) will **increase** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17709/graphs/tree.svg?src=pr&token=eZ4WkYLtcO&height=150&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17709      +/-   ##
==========================================
+ Coverage   91.24%   91.26%   +0.01%     
==========================================
  Files         163      163              
  Lines       49766    49773       +7     
==========================================
+ Hits        45411    45423      +12     
+ Misses       4355     4350       -5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.05% <100%> (+0.02%)` | :arrow_up: |
| #single | `40.33% <37.5%> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `95.06% <100%> (+0.12%)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.73% <0%> (-0.1%)` | :arrow_down: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `92.13% <0%> (+0.05%)` | :arrow_up: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.2% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=footer). Last update [074b485...3a90ea7](https://codecov.io/gh/pandas-dev/pandas/pull/17709?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).

can you rebase an respond to comments.
I do not have time right now. Sorry
Especially because I think that @TomAugspurger is right!
We need to handle timezone and test around DST transitions carefully
So I'm closing this PR. Please go ahead!